style: use Black everywhere (#2594)

* style: use Black everywhere

* style: minor touchup from review

tests/test_kwargs_and_defaults.py

@@ -15,11 +15,17 @@ def test_function_signatures(doc):
     assert doc(m.kw_func_udl) == "kw_func_udl(x: int, y: int = 300) -> str"
     assert doc(m.kw_func_udl_z) == "kw_func_udl_z(x: int, y: int = 0) -> str"
     assert doc(m.args_function) == "args_function(*args) -> tuple"
-    assert doc(m.args_kwargs_function) == "args_kwargs_function(*args, **kwargs) -> tuple"
-    assert doc(m.KWClass.foo0) == \
-        "foo0(self: m.kwargs_and_defaults.KWClass, arg0: int, arg1: float) -> None"
-    assert doc(m.KWClass.foo1) == \
-        "foo1(self: m.kwargs_and_defaults.KWClass, x: int, y: float) -> None"
+    assert (
+        doc(m.args_kwargs_function) == "args_kwargs_function(*args, **kwargs) -> tuple"
+    )
+    assert (
+        doc(m.KWClass.foo0)
+        == "foo0(self: m.kwargs_and_defaults.KWClass, arg0: int, arg1: float) -> None"
+    )
+    assert (
+        doc(m.KWClass.foo1)
+        == "foo1(self: m.kwargs_and_defaults.KWClass, x: int, y: float) -> None"
+    )
 
 
 def test_named_arguments(msg):
@@ -40,7 +46,9 @@ def test_named_arguments(msg):
         # noinspection PyArgumentList
         m.kw_func2(x=5, y=10, z=12)
     assert excinfo.match(
-        r'(?s)^kw_func2\(\): incompatible.*Invoked with: kwargs: ((x=5|y=10|z=12)(, |$))' + '{3}$')
+        r"(?s)^kw_func2\(\): incompatible.*Invoked with: kwargs: ((x=5|y=10|z=12)(, |$))"
+        + "{3}$"
+    )
 
     assert m.kw_func4() == "{13 17}"
     assert m.kw_func4(myList=[1, 2, 3]) == "{1 2 3}"
@@ -50,11 +58,11 @@ def test_named_arguments(msg):
 
 
 def test_arg_and_kwargs():
-    args = 'arg1_value', 'arg2_value', 3
+    args = "arg1_value", "arg2_value", 3
     assert m.args_function(*args) == args
 
-    args = 'a1', 'a2'
-    kwargs = dict(arg3='a3', arg4=4)
+    args = "a1", "a2"
+    kwargs = dict(arg3="a3", arg4=4)
     assert m.args_kwargs_function(*args, **kwargs) == (args, kwargs)
 
 
@@ -68,47 +76,71 @@ def test_mixed_args_and_kwargs(msg):
     assert mpa(1, 2.5) == (1, 2.5, ())
     with pytest.raises(TypeError) as excinfo:
         assert mpa(1)
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         mixed_plus_args(): incompatible function arguments. The following argument types are supported:
             1. (arg0: int, arg1: float, *args) -> tuple
 
         Invoked with: 1
     """  # noqa: E501 line too long
+    )
     with pytest.raises(TypeError) as excinfo:
         assert mpa()
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         mixed_plus_args(): incompatible function arguments. The following argument types are supported:
             1. (arg0: int, arg1: float, *args) -> tuple
 
         Invoked with:
     """  # noqa: E501 line too long
+    )
 
-    assert mpk(-2, 3.5, pi=3.14159, e=2.71828) == (-2, 3.5, {'e': 2.71828, 'pi': 3.14159})
+    assert mpk(-2, 3.5, pi=3.14159, e=2.71828) == (
+        -2,
+        3.5,
+        {"e": 2.71828, "pi": 3.14159},
+    )
     assert mpak(7, 7.7, 7.77, 7.777, 7.7777, minusseven=-7) == (
-        7, 7.7, (7.77, 7.777, 7.7777), {'minusseven': -7})
+        7,
+        7.7,
+        (7.77, 7.777, 7.7777),
+        {"minusseven": -7},
+    )
     assert mpakd() == (1, 3.14159, (), {})
     assert mpakd(3) == (3, 3.14159, (), {})
     assert mpakd(j=2.71828) == (1, 2.71828, (), {})
-    assert mpakd(k=42) == (1, 3.14159, (), {'k': 42})
+    assert mpakd(k=42) == (1, 3.14159, (), {"k": 42})
     assert mpakd(1, 1, 2, 3, 5, 8, then=13, followedby=21) == (
-        1, 1, (2, 3, 5, 8), {'then': 13, 'followedby': 21})
+        1,
+        1,
+        (2, 3, 5, 8),
+        {"then": 13, "followedby": 21},
+    )
     # Arguments specified both positionally and via kwargs should fail:
     with pytest.raises(TypeError) as excinfo:
         assert mpakd(1, i=1)
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         mixed_plus_args_kwargs_defaults(): incompatible function arguments. The following argument types are supported:
             1. (i: int = 1, j: float = 3.14159, *args, **kwargs) -> tuple
 
         Invoked with: 1; kwargs: i=1
     """  # noqa: E501 line too long
+    )
     with pytest.raises(TypeError) as excinfo:
         assert mpakd(1, 2, j=1)
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         mixed_plus_args_kwargs_defaults(): incompatible function arguments. The following argument types are supported:
             1. (i: int = 1, j: float = 3.14159, *args, **kwargs) -> tuple
 
         Invoked with: 1, 2; kwargs: j=1
     """  # noqa: E501 line too long
+    )
 
 
 def test_keyword_only_args(msg):
@@ -134,9 +166,9 @@ def test_keyword_only_args(msg):
     assert m.kw_only_mixed(j=2, i=3) == (3, 2)
     assert m.kw_only_mixed(i=2, j=3) == (2, 3)
 
-    assert m.kw_only_plus_more(4, 5, k=6, extra=7) == (4, 5, 6, {'extra': 7})
-    assert m.kw_only_plus_more(3, k=5, j=4, extra=6) == (3, 4, 5, {'extra': 6})
-    assert m.kw_only_plus_more(2, k=3, extra=4) == (2, -1, 3, {'extra': 4})
+    assert m.kw_only_plus_more(4, 5, k=6, extra=7) == (4, 5, 6, {"extra": 7})
+    assert m.kw_only_plus_more(3, k=5, j=4, extra=6) == (3, 4, 5, {"extra": 6})
+    assert m.kw_only_plus_more(2, k=3, extra=4) == (2, -1, 3, {"extra": 4})
 
     with pytest.raises(TypeError) as excinfo:
         assert m.kw_only_mixed(i=1) == (1,)
@@ -144,9 +176,12 @@ def test_keyword_only_args(msg):
 
     with pytest.raises(RuntimeError) as excinfo:
         m.register_invalid_kw_only(m)
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         arg(): cannot specify an unnamed argument after an kw_only() annotation
     """
+    )
 
 
 def test_positional_only_args(msg):
@@ -194,7 +229,10 @@ def test_signatures():
     assert "kw_only_mixed(i: int, *, j: int) -> tuple\n" == m.kw_only_mixed.__doc__
     assert "pos_only_all(i: int, j: int, /) -> tuple\n" == m.pos_only_all.__doc__
     assert "pos_only_mix(i: int, /, j: int) -> tuple\n" == m.pos_only_mix.__doc__
-    assert "pos_kw_only_mix(i: int, /, j: int, *, k: int) -> tuple\n" == m.pos_kw_only_mix.__doc__
+    assert (
+        "pos_kw_only_mix(i: int, /, j: int, *, k: int) -> tuple\n"
+        == m.pos_kw_only_mix.__doc__
+    )
 
 
 @pytest.mark.xfail("env.PYPY and env.PY2", reason="PyPy2 doesn't double count")
@@ -219,11 +257,18 @@ def test_args_refcount():
     assert m.args_function(-1, myval) == (-1, myval)
     assert refcount(myval) == expected
 
-    assert m.mixed_plus_args_kwargs(5, 6.0, myval, a=myval) == (5, 6.0, (myval,), {"a": myval})
+    assert m.mixed_plus_args_kwargs(5, 6.0, myval, a=myval) == (
+        5,
+        6.0,
+        (myval,),
+        {"a": myval},
+    )
     assert refcount(myval) == expected
 
-    assert m.args_kwargs_function(7, 8, myval, a=1, b=myval) == \
-        ((7, 8, myval), {"a": 1, "b": myval})
+    assert m.args_kwargs_function(7, 8, myval, a=1, b=myval) == (
+        (7, 8, myval),
+        {"a": 1, "b": myval},
+    )
     assert refcount(myval) == expected
 
     exp3 = refcount(myval, myval, myval)

tests/test_local_bindings.py

@@ -36,8 +36,8 @@ def test_local_bindings():
     assert i2.get() == 11
     assert i2.get2() == 12
 
-    assert not hasattr(i1, 'get2')
-    assert not hasattr(i2, 'get3')
+    assert not hasattr(i1, "get2")
+    assert not hasattr(i2, "get3")
 
     # Loading within the local module
     assert m.local_value(i1) == 5
@@ -55,7 +55,9 @@ def test_nonlocal_failure():
 
     with pytest.raises(RuntimeError) as excinfo:
         cm.register_nonlocal()
-    assert str(excinfo.value) == 'generic_type: type "NonLocalType" is already registered!'
+    assert (
+        str(excinfo.value) == 'generic_type: type "NonLocalType" is already registered!'
+    )
 
 
 def test_duplicate_local():
@@ -63,9 +65,12 @@ def test_duplicate_local():
     with pytest.raises(RuntimeError) as excinfo:
         m.register_local_external()
     import pybind11_tests
+
     assert str(excinfo.value) == (
         'generic_type: type "LocalExternal" is already registered!'
-        if hasattr(pybind11_tests, 'class_') else 'test_class not enabled')
+        if hasattr(pybind11_tests, "class_")
+        else "test_class not enabled"
+    )
 
 
 def test_stl_bind_local():
@@ -98,8 +103,8 @@ def test_stl_bind_local():
     d1["b"] = v1[1]
     d2["c"] = v2[0]
     d2["d"] = v2[1]
-    assert {i: d1[i].get() for i in d1} == {'a': 0, 'b': 1}
-    assert {i: d2[i].get() for i in d2} == {'c': 2, 'd': 3}
+    assert {i: d1[i].get() for i in d1} == {"a": 0, "b": 1}
+    assert {i: d2[i].get() for i in d2} == {"c": 2, "d": 3}
 
 
 def test_stl_bind_global():
@@ -107,15 +112,21 @@ def test_stl_bind_global():
 
     with pytest.raises(RuntimeError) as excinfo:
         cm.register_nonlocal_map()
-    assert str(excinfo.value) == 'generic_type: type "NonLocalMap" is already registered!'
+    assert (
+        str(excinfo.value) == 'generic_type: type "NonLocalMap" is already registered!'
+    )
 
     with pytest.raises(RuntimeError) as excinfo:
         cm.register_nonlocal_vec()
-    assert str(excinfo.value) == 'generic_type: type "NonLocalVec" is already registered!'
+    assert (
+        str(excinfo.value) == 'generic_type: type "NonLocalVec" is already registered!'
+    )
 
     with pytest.raises(RuntimeError) as excinfo:
         cm.register_nonlocal_map2()
-    assert str(excinfo.value) == 'generic_type: type "NonLocalMap2" is already registered!'
+    assert (
+        str(excinfo.value) == 'generic_type: type "NonLocalMap2" is already registered!'
+    )
 
 
 def test_mixed_local_global():
@@ -123,6 +134,7 @@ def test_mixed_local_global():
     type can be registered even if the type is already registered globally.  With the module,
     casting will go to the local type; outside the module casting goes to the global type."""
     import pybind11_cross_module_tests as cm
+
     m.register_mixed_global()
     m.register_mixed_local()
 
@@ -145,13 +157,26 @@ def test_mixed_local_global():
     a.append(cm.get_mixed_gl(11))
     a.append(cm.get_mixed_lg(12))
 
-    assert [x.get() for x in a] == \
-        [101, 1002, 103, 1004, 105, 1006, 207, 2008, 109, 1010, 211, 2012]
+    assert [x.get() for x in a] == [
+        101,
+        1002,
+        103,
+        1004,
+        105,
+        1006,
+        207,
+        2008,
+        109,
+        1010,
+        211,
+        2012,
+    ]
 
 
 def test_internal_locals_differ():
     """Makes sure the internal local type map differs across the two modules"""
     import pybind11_cross_module_tests as cm
+
     assert m.local_cpp_types_addr() != cm.local_cpp_types_addr()
 
 
@@ -169,12 +194,15 @@ def test_stl_caster_vs_stl_bind(msg):
     assert m.load_vector_via_caster(v2) == 6
     with pytest.raises(TypeError) as excinfo:
         cm.load_vector_via_binding(v2) == 6
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
     load_vector_via_binding(): incompatible function arguments. The following argument types are supported:
         1. (arg0: pybind11_cross_module_tests.VectorInt) -> int
 
     Invoked with: [1, 2, 3]
     """  # noqa: E501 line too long
+    )
 
 
 def test_cross_module_calls():

tests/test_methods_and_attributes.py

@@ -41,16 +41,16 @@ def test_methods_and_attributes():
     assert instance1.overloaded(1, 1.0) == "(int, float)"
     assert instance1.overloaded(2.0, 2) == "(float, int)"
     assert instance1.overloaded(3, 3) == "(int, int)"
-    assert instance1.overloaded(4., 4.) == "(float, float)"
+    assert instance1.overloaded(4.0, 4.0) == "(float, float)"
     assert instance1.overloaded_const(-3) == "(int) const"
     assert instance1.overloaded_const(5, 5.0) == "(int, float) const"
     assert instance1.overloaded_const(6.0, 6) == "(float, int) const"
     assert instance1.overloaded_const(7, 7) == "(int, int) const"
-    assert instance1.overloaded_const(8., 8.) == "(float, float) const"
+    assert instance1.overloaded_const(8.0, 8.0) == "(float, float) const"
     assert instance1.overloaded_float(1, 1) == "(float, float)"
-    assert instance1.overloaded_float(1, 1.) == "(float, float)"
-    assert instance1.overloaded_float(1., 1) == "(float, float)"
-    assert instance1.overloaded_float(1., 1.) == "(float, float)"
+    assert instance1.overloaded_float(1, 1.0) == "(float, float)"
+    assert instance1.overloaded_float(1.0, 1) == "(float, float)"
+    assert instance1.overloaded_float(1.0, 1.0) == "(float, float)"
 
     assert instance1.value == 320
     instance1.value = 100
@@ -193,7 +193,10 @@ def test_metaclass_override():
     assert type(m.MetaclassOverride).__name__ == "type"
 
     assert m.MetaclassOverride.readonly == 1
-    assert type(m.MetaclassOverride.__dict__["readonly"]).__name__ == "pybind11_static_property"
+    assert (
+        type(m.MetaclassOverride.__dict__["readonly"]).__name__
+        == "pybind11_static_property"
+    )
 
     # Regular `type` replaces the property instead of calling `__set__()`
     m.MetaclassOverride.readonly = 2
@@ -206,21 +209,25 @@ def test_no_mixed_overloads():
 
     with pytest.raises(RuntimeError) as excinfo:
         m.ExampleMandA.add_mixed_overloads1()
-    assert (str(excinfo.value) ==
-            "overloading a method with both static and instance methods is not supported; " +
-            ("compile in debug mode for more details" if not debug_enabled else
-             "error while attempting to bind static method ExampleMandA.overload_mixed1"
-             "(arg0: float) -> str")
+    assert str(
+        excinfo.value
+    ) == "overloading a method with both static and instance methods is not supported; " + (
+        "compile in debug mode for more details"
+        if not debug_enabled
+        else "error while attempting to bind static method ExampleMandA.overload_mixed1"
+        "(arg0: float) -> str"
     )
 
     with pytest.raises(RuntimeError) as excinfo:
         m.ExampleMandA.add_mixed_overloads2()
-    assert (str(excinfo.value) ==
-            "overloading a method with both static and instance methods is not supported; " +
-            ("compile in debug mode for more details" if not debug_enabled else
-             "error while attempting to bind instance method ExampleMandA.overload_mixed2"
+    assert str(
+        excinfo.value
+    ) == "overloading a method with both static and instance methods is not supported; " + (
+        "compile in debug mode for more details"
+        if not debug_enabled
+        else "error while attempting to bind instance method ExampleMandA.overload_mixed2"
         "(self: pybind11_tests.methods_and_attributes.ExampleMandA, arg0: int, arg1: int)"
-             " -> str")
+        " -> str"
     )
 
 
@@ -333,8 +340,8 @@ def test_bad_arg_default(msg):
     assert msg(excinfo.value) == (
         "arg(): could not convert default argument 'a: UnregisteredType' in function "
         "'should_fail' into a Python object (type not registered yet?)"
-        if debug_enabled else
-        "arg(): could not convert default argument into a Python object (type not registered "
+        if debug_enabled
+        else "arg(): could not convert default argument into a Python object (type not registered "
         "yet?). Compile in debug mode for more information."
     )
 
@@ -343,8 +350,8 @@ def test_bad_arg_default(msg):
     assert msg(excinfo.value) == (
         "arg(): could not convert default argument 'UnregisteredType' in function "
         "'should_fail' into a Python object (type not registered yet?)"
-        if debug_enabled else
-        "arg(): could not convert default argument into a Python object (type not registered "
+        if debug_enabled
+        else "arg(): could not convert default argument into a Python object (type not registered "
         "yet?). Compile in debug mode for more information."
     )
 
@@ -381,12 +388,15 @@ def test_accepts_none(msg):
     # The first one still raises because you can't pass None as a lvalue reference arg:
     with pytest.raises(TypeError) as excinfo:
         assert m.ok_none1(None) == -1
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         ok_none1(): incompatible function arguments. The following argument types are supported:
             1. (arg0: m.methods_and_attributes.NoneTester) -> int
 
         Invoked with: None
     """
+    )
 
     # The rest take the argument as pointer or holder, and accept None:
     assert m.ok_none2(None) == -1
@@ -402,13 +412,16 @@ def test_str_issue(msg):
 
     with pytest.raises(TypeError) as excinfo:
         str(m.StrIssue("no", "such", "constructor"))
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         __init__(): incompatible constructor arguments. The following argument types are supported:
             1. m.methods_and_attributes.StrIssue(arg0: int)
             2. m.methods_and_attributes.StrIssue()
 
         Invoked with: 'no', 'such', 'constructor'
     """
+    )
 
 
 def test_unregistered_base_implementations():
@@ -441,7 +454,7 @@ def test_ref_qualified():
 
 
 def test_overload_ordering():
-    'Check to see if the normal overload order (first defined) and prepend overload order works'
+    "Check to see if the normal overload order (first defined) and prepend overload order works"
     assert m.overload_order("string") == 1
     assert m.overload_order(0) == 4
 
@@ -449,8 +462,14 @@ def test_overload_ordering():
     uni_name = type(u"").__name__
 
     assert "1. overload_order(arg0: int) -> int" in m.overload_order.__doc__
-    assert "2. overload_order(arg0: {}) -> int".format(uni_name) in m.overload_order.__doc__
-    assert "3. overload_order(arg0: {}) -> int".format(uni_name) in m.overload_order.__doc__
+    assert (
+        "2. overload_order(arg0: {}) -> int".format(uni_name)
+        in m.overload_order.__doc__
+    )
+    assert (
+        "3. overload_order(arg0: {}) -> int".format(uni_name)
+        in m.overload_order.__doc__
+    )
     assert "4. overload_order(arg0: int) -> int" in m.overload_order.__doc__
 
     with pytest.raises(TypeError) as err:

tests/test_modules.py

@@ -6,9 +6,13 @@ from pybind11_tests import ConstructorStats
 
 def test_nested_modules():
     import pybind11_tests
+
     assert pybind11_tests.__name__ == "pybind11_tests"
     assert pybind11_tests.modules.__name__ == "pybind11_tests.modules"
-    assert pybind11_tests.modules.subsubmodule.__name__ == "pybind11_tests.modules.subsubmodule"
+    assert (
+        pybind11_tests.modules.subsubmodule.__name__
+        == "pybind11_tests.modules.subsubmodule"
+    )
     assert m.__name__ == "pybind11_tests.modules"
     assert ms.__name__ == "pybind11_tests.modules.subsubmodule"
 
@@ -35,7 +39,7 @@ def test_reference_internal():
     del b
     assert astats.alive() == 0
     assert bstats.alive() == 0
-    assert astats.values() == ['1', '2', '42', '43']
+    assert astats.values() == ["1", "2", "42", "43"]
     assert bstats.values() == []
     assert astats.default_constructions == 0
     assert bstats.default_constructions == 1
@@ -54,7 +58,7 @@ def test_importing():
     from collections import OrderedDict
 
     assert OD is OrderedDict
-    assert str(OD([(1, 'a'), (2, 'b')])) == "OrderedDict([(1, 'a'), (2, 'b')])"
+    assert str(OD([(1, "a"), (2, "b")])) == "OrderedDict([(1, 'a'), (2, 'b')])"
 
 
 def test_pydoc():

tests/test_multiple_inheritance.py

@@ -57,7 +57,6 @@ def test_multiple_inheritance_mix2():
 @pytest.mark.skipif("env.PYPY and env.PY2")
 @pytest.mark.xfail("env.PYPY and not env.PY2")
 def test_multiple_inheritance_python():
-
     class MI1(m.Base1, m.Base2):
         def __init__(self, i, j):
             m.Base1.__init__(self, i)
@@ -163,7 +162,6 @@ def test_multiple_inheritance_python():
 
 
 def test_multiple_inheritance_python_many_bases():
-
     class MIMany14(m.BaseN1, m.BaseN2, m.BaseN3, m.BaseN4):
         def __init__(self):
             m.BaseN1.__init__(self, 1)
@@ -178,8 +176,16 @@ def test_multiple_inheritance_python_many_bases():
             m.BaseN7.__init__(self, 7)
             m.BaseN8.__init__(self, 8)
 
-    class MIMany916(m.BaseN9, m.BaseN10, m.BaseN11, m.BaseN12, m.BaseN13, m.BaseN14, m.BaseN15,
-                    m.BaseN16):
+    class MIMany916(
+        m.BaseN9,
+        m.BaseN10,
+        m.BaseN11,
+        m.BaseN12,
+        m.BaseN13,
+        m.BaseN14,
+        m.BaseN15,
+        m.BaseN16,
+    ):
         def __init__(self):
             m.BaseN9.__init__(self, 9)
             m.BaseN10.__init__(self, 10)
@@ -225,7 +231,6 @@ def test_multiple_inheritance_python_many_bases():
 
 
 def test_multiple_inheritance_virtbase():
-
     class MITypePy(m.Base12a):
         def __init__(self, i, j):
             m.Base12a.__init__(self, i, j)

tests/test_numpy_array.py

@@ -19,33 +19,36 @@ def test_dtypes():
         print(check)
         assert check.numpy == check.pybind11, check
         if check.numpy.num != check.pybind11.num:
-            print("NOTE: typenum mismatch for {}: {} != {}".format(
-                check, check.numpy.num, check.pybind11.num))
+            print(
+                "NOTE: typenum mismatch for {}: {} != {}".format(
+                    check, check.numpy.num, check.pybind11.num
+                )
+            )
 
 
-@pytest.fixture(scope='function')
+@pytest.fixture(scope="function")
 def arr():
-    return np.array([[1, 2, 3], [4, 5, 6]], '=u2')
+    return np.array([[1, 2, 3], [4, 5, 6]], "=u2")
 
 
 def test_array_attributes():
-    a = np.array(0, 'f8')
+    a = np.array(0, "f8")
     assert m.ndim(a) == 0
     assert all(m.shape(a) == [])
     assert all(m.strides(a) == [])
     with pytest.raises(IndexError) as excinfo:
         m.shape(a, 0)
-    assert str(excinfo.value) == 'invalid axis: 0 (ndim = 0)'
+    assert str(excinfo.value) == "invalid axis: 0 (ndim = 0)"
     with pytest.raises(IndexError) as excinfo:
         m.strides(a, 0)
-    assert str(excinfo.value) == 'invalid axis: 0 (ndim = 0)'
+    assert str(excinfo.value) == "invalid axis: 0 (ndim = 0)"
     assert m.writeable(a)
     assert m.size(a) == 1
     assert m.itemsize(a) == 8
     assert m.nbytes(a) == 8
     assert m.owndata(a)
 
-    a = np.array([[1, 2, 3], [4, 5, 6]], 'u2').view()
+    a = np.array([[1, 2, 3], [4, 5, 6]], "u2").view()
     a.flags.writeable = False
     assert m.ndim(a) == 2
     assert all(m.shape(a) == [2, 3])
@@ -56,10 +59,10 @@ def test_array_attributes():
     assert m.strides(a, 1) == 2
     with pytest.raises(IndexError) as excinfo:
         m.shape(a, 2)
-    assert str(excinfo.value) == 'invalid axis: 2 (ndim = 2)'
+    assert str(excinfo.value) == "invalid axis: 2 (ndim = 2)"
     with pytest.raises(IndexError) as excinfo:
         m.strides(a, 2)
-    assert str(excinfo.value) == 'invalid axis: 2 (ndim = 2)'
+    assert str(excinfo.value) == "invalid axis: 2 (ndim = 2)"
     assert not m.writeable(a)
     assert m.size(a) == 6
     assert m.itemsize(a) == 2
@@ -67,7 +70,9 @@ def test_array_attributes():
     assert not m.owndata(a)
 
 
-@pytest.mark.parametrize('args, ret', [([], 0), ([0], 0), ([1], 3), ([0, 1], 1), ([1, 2], 5)])
+@pytest.mark.parametrize(
+    "args, ret", [([], 0), ([0], 0), ([1], 3), ([0, 1], 1), ([1, 2], 5)]
+)
 def test_index_offset(arr, args, ret):
     assert m.index_at(arr, *args) == ret
     assert m.index_at_t(arr, *args) == ret
@@ -76,31 +81,46 @@ def test_index_offset(arr, args, ret):
 
 
 def test_dim_check_fail(arr):
-    for func in (m.index_at, m.index_at_t, m.offset_at, m.offset_at_t, m.data, m.data_t,
-                 m.mutate_data, m.mutate_data_t):
+    for func in (
+        m.index_at,
+        m.index_at_t,
+        m.offset_at,
+        m.offset_at_t,
+        m.data,
+        m.data_t,
+        m.mutate_data,
+        m.mutate_data_t,
+    ):
         with pytest.raises(IndexError) as excinfo:
             func(arr, 1, 2, 3)
-        assert str(excinfo.value) == 'too many indices for an array: 3 (ndim = 2)'
+        assert str(excinfo.value) == "too many indices for an array: 3 (ndim = 2)"
 
 
-@pytest.mark.parametrize('args, ret',
-                         [([], [1, 2, 3, 4, 5, 6]),
+@pytest.mark.parametrize(
+    "args, ret",
+    [
+        ([], [1, 2, 3, 4, 5, 6]),
         ([1], [4, 5, 6]),
         ([0, 1], [2, 3, 4, 5, 6]),
-                          ([1, 2], [6])])
+        ([1, 2], [6]),
+    ],
+)
 def test_data(arr, args, ret):
     from sys import byteorder
+
     assert all(m.data_t(arr, *args) == ret)
-    assert all(m.data(arr, *args)[(0 if byteorder == 'little' else 1)::2] == ret)
-    assert all(m.data(arr, *args)[(1 if byteorder == 'little' else 0)::2] == 0)
+    assert all(m.data(arr, *args)[(0 if byteorder == "little" else 1) :: 2] == ret)
+    assert all(m.data(arr, *args)[(1 if byteorder == "little" else 0) :: 2] == 0)
 
 
-@pytest.mark.parametrize('dim', [0, 1, 3])
+@pytest.mark.parametrize("dim", [0, 1, 3])
 def test_at_fail(arr, dim):
     for func in m.at_t, m.mutate_at_t:
         with pytest.raises(IndexError) as excinfo:
             func(arr, *([0] * dim))
-        assert str(excinfo.value) == 'index dimension mismatch: {} (ndim = 2)'.format(dim)
+        assert str(excinfo.value) == "index dimension mismatch: {} (ndim = 2)".format(
+            dim
+        )
 
 
 def test_at(arr):
@@ -113,10 +133,14 @@ def test_at(arr):
 
 def test_mutate_readonly(arr):
     arr.flags.writeable = False
-    for func, args in (m.mutate_data, ()), (m.mutate_data_t, ()), (m.mutate_at_t, (0, 0)):
+    for func, args in (
+        (m.mutate_data, ()),
+        (m.mutate_data_t, ()),
+        (m.mutate_at_t, (0, 0)),
+    ):
         with pytest.raises(ValueError) as excinfo:
             func(arr, *args)
-        assert str(excinfo.value) == 'array is not writeable'
+        assert str(excinfo.value) == "array is not writeable"
 
 
 def test_mutate_data(arr):
@@ -134,14 +158,22 @@ def test_mutate_data(arr):
 
 
 def test_bounds_check(arr):
-    for func in (m.index_at, m.index_at_t, m.data, m.data_t,
-                 m.mutate_data, m.mutate_data_t, m.at_t, m.mutate_at_t):
+    for func in (
+        m.index_at,
+        m.index_at_t,
+        m.data,
+        m.data_t,
+        m.mutate_data,
+        m.mutate_data_t,
+        m.at_t,
+        m.mutate_at_t,
+    ):
         with pytest.raises(IndexError) as excinfo:
             func(arr, 2, 0)
-        assert str(excinfo.value) == 'index 2 is out of bounds for axis 0 with size 2'
+        assert str(excinfo.value) == "index 2 is out of bounds for axis 0 with size 2"
         with pytest.raises(IndexError) as excinfo:
             func(arr, 0, 4)
-        assert str(excinfo.value) == 'index 4 is out of bounds for axis 1 with size 3'
+        assert str(excinfo.value) == "index 4 is out of bounds for axis 1 with size 3"
 
 
 def test_make_c_f_array():
@@ -163,10 +195,11 @@ def test_make_empty_shaped_array():
 def test_wrap():
     def assert_references(a, b, base=None):
         from distutils.version import LooseVersion
+
         if base is None:
             base = a
         assert a is not b
-        assert a.__array_interface__['data'][0] == b.__array_interface__['data'][0]
+        assert a.__array_interface__["data"][0] == b.__array_interface__["data"][0]
         assert a.shape == b.shape
         assert a.strides == b.strides
         assert a.flags.c_contiguous == b.flags.c_contiguous
@@ -189,12 +222,12 @@ def test_wrap():
     a2 = m.wrap(a1)
     assert_references(a1, a2)
 
-    a1 = np.array([[1, 2], [3, 4]], dtype=np.float32, order='F')
+    a1 = np.array([[1, 2], [3, 4]], dtype=np.float32, order="F")
     assert a1.flags.owndata and a1.base is None
     a2 = m.wrap(a1)
     assert_references(a1, a2)
 
-    a1 = np.array([[1, 2], [3, 4]], dtype=np.float32, order='C')
+    a1 = np.array([[1, 2], [3, 4]], dtype=np.float32, order="C")
     a1.flags.writeable = False
     a2 = m.wrap(a1)
     assert_references(a1, a2)
@@ -224,11 +257,14 @@ def test_numpy_view(capture):
         assert np.all(ac_view_1 == np.array([1, 2], dtype=np.int32))
         del ac
         pytest.gc_collect()
-    assert capture == """
+    assert (
+        capture
+        == """
         ArrayClass()
         ArrayClass::numpy_view()
         ArrayClass::numpy_view()
     """
+    )
     ac_view_1[0] = 4
     ac_view_1[1] = 3
     assert ac_view_2[0] == 4
@@ -238,9 +274,12 @@ def test_numpy_view(capture):
         del ac_view_2
         pytest.gc_collect()
         pytest.gc_collect()
-    assert capture == """
+    assert (
+        capture
+        == """
         ~ArrayClass()
     """
+    )
 
 
 def test_cast_numpy_int64_to_uint64():
@@ -271,20 +310,22 @@ def test_constructors():
 
 def test_overload_resolution(msg):
     # Exact overload matches:
-    assert m.overloaded(np.array([1], dtype='float64')) == 'double'
-    assert m.overloaded(np.array([1], dtype='float32')) == 'float'
-    assert m.overloaded(np.array([1], dtype='ushort')) == 'unsigned short'
-    assert m.overloaded(np.array([1], dtype='intc')) == 'int'
-    assert m.overloaded(np.array([1], dtype='longlong')) == 'long long'
-    assert m.overloaded(np.array([1], dtype='complex')) == 'double complex'
-    assert m.overloaded(np.array([1], dtype='csingle')) == 'float complex'
+    assert m.overloaded(np.array([1], dtype="float64")) == "double"
+    assert m.overloaded(np.array([1], dtype="float32")) == "float"
+    assert m.overloaded(np.array([1], dtype="ushort")) == "unsigned short"
+    assert m.overloaded(np.array([1], dtype="intc")) == "int"
+    assert m.overloaded(np.array([1], dtype="longlong")) == "long long"
+    assert m.overloaded(np.array([1], dtype="complex")) == "double complex"
+    assert m.overloaded(np.array([1], dtype="csingle")) == "float complex"
 
     # No exact match, should call first convertible version:
-    assert m.overloaded(np.array([1], dtype='uint8')) == 'double'
+    assert m.overloaded(np.array([1], dtype="uint8")) == "double"
 
     with pytest.raises(TypeError) as excinfo:
         m.overloaded("not an array")
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         overloaded(): incompatible function arguments. The following argument types are supported:
             1. (arg0: numpy.ndarray[numpy.float64]) -> str
             2. (arg0: numpy.ndarray[numpy.float32]) -> str
@@ -296,15 +337,16 @@ def test_overload_resolution(msg):
 
         Invoked with: 'not an array'
     """
+    )
 
-    assert m.overloaded2(np.array([1], dtype='float64')) == 'double'
-    assert m.overloaded2(np.array([1], dtype='float32')) == 'float'
-    assert m.overloaded2(np.array([1], dtype='complex64')) == 'float complex'
-    assert m.overloaded2(np.array([1], dtype='complex128')) == 'double complex'
-    assert m.overloaded2(np.array([1], dtype='float32')) == 'float'
+    assert m.overloaded2(np.array([1], dtype="float64")) == "double"
+    assert m.overloaded2(np.array([1], dtype="float32")) == "float"
+    assert m.overloaded2(np.array([1], dtype="complex64")) == "float complex"
+    assert m.overloaded2(np.array([1], dtype="complex128")) == "double complex"
+    assert m.overloaded2(np.array([1], dtype="float32")) == "float"
 
-    assert m.overloaded3(np.array([1], dtype='float64')) == 'double'
-    assert m.overloaded3(np.array([1], dtype='intc')) == 'int'
+    assert m.overloaded3(np.array([1], dtype="float64")) == "double"
+    assert m.overloaded3(np.array([1], dtype="intc")) == "int"
     expected_exc = """
         overloaded3(): incompatible function arguments. The following argument types are supported:
             1. (arg0: numpy.ndarray[numpy.int32]) -> str
@@ -313,47 +355,49 @@ def test_overload_resolution(msg):
         Invoked with: """
 
     with pytest.raises(TypeError) as excinfo:
-        m.overloaded3(np.array([1], dtype='uintc'))
-    assert msg(excinfo.value) == expected_exc + repr(np.array([1], dtype='uint32'))
+        m.overloaded3(np.array([1], dtype="uintc"))
+    assert msg(excinfo.value) == expected_exc + repr(np.array([1], dtype="uint32"))
     with pytest.raises(TypeError) as excinfo:
-        m.overloaded3(np.array([1], dtype='float32'))
-    assert msg(excinfo.value) == expected_exc + repr(np.array([1.], dtype='float32'))
+        m.overloaded3(np.array([1], dtype="float32"))
+    assert msg(excinfo.value) == expected_exc + repr(np.array([1.0], dtype="float32"))
     with pytest.raises(TypeError) as excinfo:
-        m.overloaded3(np.array([1], dtype='complex'))
-    assert msg(excinfo.value) == expected_exc + repr(np.array([1. + 0.j]))
+        m.overloaded3(np.array([1], dtype="complex"))
+    assert msg(excinfo.value) == expected_exc + repr(np.array([1.0 + 0.0j]))
 
     # Exact matches:
-    assert m.overloaded4(np.array([1], dtype='double')) == 'double'
-    assert m.overloaded4(np.array([1], dtype='longlong')) == 'long long'
+    assert m.overloaded4(np.array([1], dtype="double")) == "double"
+    assert m.overloaded4(np.array([1], dtype="longlong")) == "long long"
     # Non-exact matches requiring conversion.  Since float to integer isn't a
     # save conversion, it should go to the double overload, but short can go to
     # either (and so should end up on the first-registered, the long long).
-    assert m.overloaded4(np.array([1], dtype='float32')) == 'double'
-    assert m.overloaded4(np.array([1], dtype='short')) == 'long long'
+    assert m.overloaded4(np.array([1], dtype="float32")) == "double"
+    assert m.overloaded4(np.array([1], dtype="short")) == "long long"
 
-    assert m.overloaded5(np.array([1], dtype='double')) == 'double'
-    assert m.overloaded5(np.array([1], dtype='uintc')) == 'unsigned int'
-    assert m.overloaded5(np.array([1], dtype='float32')) == 'unsigned int'
+    assert m.overloaded5(np.array([1], dtype="double")) == "double"
+    assert m.overloaded5(np.array([1], dtype="uintc")) == "unsigned int"
+    assert m.overloaded5(np.array([1], dtype="float32")) == "unsigned int"
 
 
 def test_greedy_string_overload():
     """Tests fix for #685 - ndarray shouldn't go to std::string overload"""
 
     assert m.issue685("abc") == "string"
-    assert m.issue685(np.array([97, 98, 99], dtype='b')) == "array"
+    assert m.issue685(np.array([97, 98, 99], dtype="b")) == "array"
     assert m.issue685(123) == "other"
 
 
 def test_array_unchecked_fixed_dims(msg):
-    z1 = np.array([[1, 2], [3, 4]], dtype='float64')
+    z1 = np.array([[1, 2], [3, 4]], dtype="float64")
     m.proxy_add2(z1, 10)
     assert np.all(z1 == [[11, 12], [13, 14]])
 
     with pytest.raises(ValueError) as excinfo:
-        m.proxy_add2(np.array([1., 2, 3]), 5.0)
-    assert msg(excinfo.value) == "array has incorrect number of dimensions: 1; expected 2"
+        m.proxy_add2(np.array([1.0, 2, 3]), 5.0)
+    assert (
+        msg(excinfo.value) == "array has incorrect number of dimensions: 1; expected 2"
+    )
 
-    expect_c = np.ndarray(shape=(3, 3, 3), buffer=np.array(range(3, 30)), dtype='int')
+    expect_c = np.ndarray(shape=(3, 3, 3), buffer=np.array(range(3, 30)), dtype="int")
     assert np.all(m.proxy_init3(3.0) == expect_c)
     expect_f = np.transpose(expect_c)
     assert np.all(m.proxy_init3F(3.0) == expect_f)
@@ -369,11 +413,11 @@ def test_array_unchecked_fixed_dims(msg):
 
 
 def test_array_unchecked_dyn_dims(msg):
-    z1 = np.array([[1, 2], [3, 4]], dtype='float64')
+    z1 = np.array([[1, 2], [3, 4]], dtype="float64")
     m.proxy_add2_dyn(z1, 10)
     assert np.all(z1 == [[11, 12], [13, 14]])
 
-    expect_c = np.ndarray(shape=(3, 3, 3), buffer=np.array(range(3, 30)), dtype='int')
+    expect_c = np.ndarray(shape=(3, 3, 3), buffer=np.array(range(3, 30)), dtype="int")
     assert np.all(m.proxy_init3_dyn(3.0) == expect_c)
 
     assert m.proxy_auxiliaries2_dyn(z1) == [11, 11, True, 2, 8, 2, 2, 4, 32]
@@ -383,15 +427,15 @@ def test_array_unchecked_dyn_dims(msg):
 def test_array_failure():
     with pytest.raises(ValueError) as excinfo:
         m.array_fail_test()
-    assert str(excinfo.value) == 'cannot create a pybind11::array from a nullptr'
+    assert str(excinfo.value) == "cannot create a pybind11::array from a nullptr"
 
     with pytest.raises(ValueError) as excinfo:
         m.array_t_fail_test()
-    assert str(excinfo.value) == 'cannot create a pybind11::array_t from a nullptr'
+    assert str(excinfo.value) == "cannot create a pybind11::array_t from a nullptr"
 
     with pytest.raises(ValueError) as excinfo:
         m.array_fail_test_negative_size()
-    assert str(excinfo.value) == 'negative dimensions are not allowed'
+    assert str(excinfo.value) == "negative dimensions are not allowed"
 
 
 def test_initializer_list():
@@ -402,35 +446,35 @@ def test_initializer_list():
 
 
 def test_array_resize(msg):
-    a = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9], dtype='float64')
+    a = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9], dtype="float64")
     m.array_reshape2(a)
-    assert(a.size == 9)
-    assert(np.all(a == [[1, 2, 3], [4, 5, 6], [7, 8, 9]]))
+    assert a.size == 9
+    assert np.all(a == [[1, 2, 3], [4, 5, 6], [7, 8, 9]])
 
     # total size change should succced with refcheck off
     m.array_resize3(a, 4, False)
-    assert(a.size == 64)
+    assert a.size == 64
     # ... and fail with refcheck on
     try:
         m.array_resize3(a, 3, True)
     except ValueError as e:
-        assert(str(e).startswith("cannot resize an array"))
+        assert str(e).startswith("cannot resize an array")
     # transposed array doesn't own data
     b = a.transpose()
     try:
         m.array_resize3(b, 3, False)
     except ValueError as e:
-        assert(str(e).startswith("cannot resize this array: it does not own its data"))
+        assert str(e).startswith("cannot resize this array: it does not own its data")
     # ... but reshape should be fine
     m.array_reshape2(b)
-    assert(b.shape == (8, 8))
+    assert b.shape == (8, 8)
 
 
 @pytest.mark.xfail("env.PYPY")
 def test_array_create_and_resize(msg):
     a = m.create_and_resize(2)
-    assert(a.size == 4)
-    assert(np.all(a == 42.))
+    assert a.size == 4
+    assert np.all(a == 42.0)
 
 
 def test_index_using_ellipsis():
@@ -439,16 +483,16 @@ def test_index_using_ellipsis():
 
 
 @pytest.mark.parametrize("forcecast", [False, True])
-@pytest.mark.parametrize("contiguity", [None, 'C', 'F'])
+@pytest.mark.parametrize("contiguity", [None, "C", "F"])
 @pytest.mark.parametrize("noconvert", [False, True])
 @pytest.mark.filterwarnings(
     "ignore:Casting complex values to real discards the imaginary part:numpy.ComplexWarning"
 )
 def test_argument_conversions(forcecast, contiguity, noconvert):
     function_name = "accept_double"
-    if contiguity == 'C':
+    if contiguity == "C":
         function_name += "_c_style"
-    elif contiguity == 'F':
+    elif contiguity == "F":
         function_name += "_f_style"
     if forcecast:
         function_name += "_forcecast"
@@ -456,37 +500,39 @@ def test_argument_conversions(forcecast, contiguity, noconvert):
         function_name += "_noconvert"
     function = getattr(m, function_name)
 
-    for dtype in [np.dtype('float32'), np.dtype('float64'), np.dtype('complex128')]:
-        for order in ['C', 'F']:
+    for dtype in [np.dtype("float32"), np.dtype("float64"), np.dtype("complex128")]:
+        for order in ["C", "F"]:
             for shape in [(2, 2), (1, 3, 1, 1), (1, 1, 1), (0,)]:
                 if not noconvert:
                     # If noconvert is not passed, only complex128 needs to be truncated and
                     # "cannot be safely obtained". So without `forcecast`, the argument shouldn't
                     # be accepted.
-                    should_raise = dtype.name == 'complex128' and not forcecast
+                    should_raise = dtype.name == "complex128" and not forcecast
                 else:
                     # If noconvert is passed, only float64 and the matching order is accepted.
                     # If at most one dimension has a size greater than 1, the array is also
                     # trivially contiguous.
                     trivially_contiguous = sum(1 for d in shape if d > 1) <= 1
-                    should_raise = (
-                        dtype.name != 'float64' or
-                        (contiguity is not None and
-                         contiguity != order and
-                         not trivially_contiguous)
+                    should_raise = dtype.name != "float64" or (
+                        contiguity is not None
+                        and contiguity != order
+                        and not trivially_contiguous
                     )
 
                 array = np.zeros(shape, dtype=dtype, order=order)
                 if not should_raise:
                     function(array)
                 else:
-                    with pytest.raises(TypeError, match="incompatible function arguments"):
+                    with pytest.raises(
+                        TypeError, match="incompatible function arguments"
+                    ):
                         function(array)
 
 
 @pytest.mark.xfail("env.PYPY")
 def test_dtype_refcount_leak():
     from sys import getrefcount
+
     dtype = np.dtype(np.float_)
     a = np.array([1], dtype=dtype)
     before = getrefcount(dtype)

tests/test_numpy_dtypes.py

@@ -10,57 +10,71 @@ from pybind11_tests import numpy_dtypes as m
 np = pytest.importorskip("numpy")
 
 
-@pytest.fixture(scope='module')
+@pytest.fixture(scope="module")
 def simple_dtype():
-    ld = np.dtype('longdouble')
-    return np.dtype({'names': ['bool_', 'uint_', 'float_', 'ldbl_'],
-                     'formats': ['?', 'u4', 'f4', 'f{}'.format(ld.itemsize)],
-                     'offsets': [0, 4, 8, (16 if ld.alignment > 4 else 12)]})
+    ld = np.dtype("longdouble")
+    return np.dtype(
+        {
+            "names": ["bool_", "uint_", "float_", "ldbl_"],
+            "formats": ["?", "u4", "f4", "f{}".format(ld.itemsize)],
+            "offsets": [0, 4, 8, (16 if ld.alignment > 4 else 12)],
+        }
+    )
 
 
-@pytest.fixture(scope='module')
+@pytest.fixture(scope="module")
 def packed_dtype():
-    return np.dtype([('bool_', '?'), ('uint_', 'u4'), ('float_', 'f4'), ('ldbl_', 'g')])
+    return np.dtype([("bool_", "?"), ("uint_", "u4"), ("float_", "f4"), ("ldbl_", "g")])
 
 
 def dt_fmt():
     from sys import byteorder
-    e = '<' if byteorder == 'little' else '>'
-    return ("{{'names':['bool_','uint_','float_','ldbl_'],"
+
+    e = "<" if byteorder == "little" else ">"
+    return (
+        "{{'names':['bool_','uint_','float_','ldbl_'],"
         " 'formats':['?','" + e + "u4','" + e + "f4','" + e + "f{}'],"
-            " 'offsets':[0,4,8,{}], 'itemsize':{}}}")
+        " 'offsets':[0,4,8,{}], 'itemsize':{}}}"
+    )
 
 
 def simple_dtype_fmt():
-    ld = np.dtype('longdouble')
+    ld = np.dtype("longdouble")
     simple_ld_off = 12 + 4 * (ld.alignment > 4)
     return dt_fmt().format(ld.itemsize, simple_ld_off, simple_ld_off + ld.itemsize)
 
 
 def packed_dtype_fmt():
     from sys import byteorder
+
     return "[('bool_', '?'), ('uint_', '{e}u4'), ('float_', '{e}f4'), ('ldbl_', '{e}f{}')]".format(
-        np.dtype('longdouble').itemsize, e='<' if byteorder == 'little' else '>')
+        np.dtype("longdouble").itemsize, e="<" if byteorder == "little" else ">"
+    )
 
 
 def partial_ld_offset():
-    return 12 + 4 * (np.dtype('uint64').alignment > 4) + 8 + 8 * (
-        np.dtype('longdouble').alignment > 8)
+    return (
+        12
+        + 4 * (np.dtype("uint64").alignment > 4)
+        + 8
+        + 8 * (np.dtype("longdouble").alignment > 8)
+    )
 
 
 def partial_dtype_fmt():
-    ld = np.dtype('longdouble')
+    ld = np.dtype("longdouble")
     partial_ld_off = partial_ld_offset()
     return dt_fmt().format(ld.itemsize, partial_ld_off, partial_ld_off + ld.itemsize)
 
 
 def partial_nested_fmt():
-    ld = np.dtype('longdouble')
+    ld = np.dtype("longdouble")
     partial_nested_off = 8 + 8 * (ld.alignment > 8)
     partial_ld_off = partial_ld_offset()
     partial_nested_size = partial_nested_off * 2 + partial_ld_off + ld.itemsize
     return "{{'names':['a'], 'formats':[{}], 'offsets':[{}], 'itemsize':{}}}".format(
-        partial_dtype_fmt(), partial_nested_off, partial_nested_size)
+        partial_dtype_fmt(), partial_nested_off, partial_nested_size
+    )
 
 
 def assert_equal(actual, expected_data, expected_dtype):
@@ -70,15 +84,19 @@ def assert_equal(actual, expected_data, expected_dtype):
 def test_format_descriptors():
     with pytest.raises(RuntimeError) as excinfo:
         m.get_format_unbound()
-    assert re.match('^NumPy type info missing for .*UnboundStruct.*$', str(excinfo.value))
+    assert re.match(
+        "^NumPy type info missing for .*UnboundStruct.*$", str(excinfo.value)
+    )
 
-    ld = np.dtype('longdouble')
-    ldbl_fmt = ('4x' if ld.alignment > 4 else '') + ld.char
+    ld = np.dtype("longdouble")
+    ldbl_fmt = ("4x" if ld.alignment > 4 else "") + ld.char
     ss_fmt = "^T{?:bool_:3xI:uint_:f:float_:" + ldbl_fmt + ":ldbl_:}"
-    dbl = np.dtype('double')
-    partial_fmt = ("^T{?:bool_:3xI:uint_:f:float_:" +
-                   str(4 * (dbl.alignment > 4) + dbl.itemsize + 8 * (ld.alignment > 8)) +
-                   "xg:ldbl_:}")
+    dbl = np.dtype("double")
+    partial_fmt = (
+        "^T{?:bool_:3xI:uint_:f:float_:"
+        + str(4 * (dbl.alignment > 4) + dbl.itemsize + 8 * (ld.alignment > 8))
+        + "xg:ldbl_:}"
+    )
     nested_extra = str(max(8, ld.alignment))
     assert m.print_format_descriptors() == [
         ss_fmt,
@@ -88,14 +106,15 @@ def test_format_descriptors():
         "^T{" + nested_extra + "x" + partial_fmt + ":a:" + nested_extra + "x}",
         "^T{3s:a:3s:b:}",
         "^T{(3)4s:a:(2)i:b:(3)B:c:1x(4, 2)f:d:}",
-        '^T{q:e1:B:e2:}',
-        '^T{Zf:cflt:Zd:cdbl:}'
+        "^T{q:e1:B:e2:}",
+        "^T{Zf:cflt:Zd:cdbl:}",
     ]
 
 
 def test_dtype(simple_dtype):
     from sys import byteorder
-    e = '<' if byteorder == 'little' else '>'
+
+    e = "<" if byteorder == "little" else ">"
 
     assert m.print_dtypes() == [
         simple_dtype_fmt(),
@@ -104,30 +123,60 @@ def test_dtype(simple_dtype):
         partial_dtype_fmt(),
         partial_nested_fmt(),
         "[('a', 'S3'), ('b', 'S3')]",
-        ("{{'names':['a','b','c','d'], " +
-         "'formats':[('S4', (3,)),('" + e + "i4', (2,)),('u1', (3,)),('" + e + "f4', (4, 2))], " +
-         "'offsets':[0,12,20,24], 'itemsize':56}}").format(e=e),
+        (
+            "{{'names':['a','b','c','d'], "
+            + "'formats':[('S4', (3,)),('"
+            + e
+            + "i4', (2,)),('u1', (3,)),('"
+            + e
+            + "f4', (4, 2))], "
+            + "'offsets':[0,12,20,24], 'itemsize':56}}"
+        ).format(e=e),
         "[('e1', '" + e + "i8'), ('e2', 'u1')]",
         "[('x', 'i1'), ('y', '" + e + "u8')]",
-        "[('cflt', '" + e + "c8'), ('cdbl', '" + e + "c16')]"
+        "[('cflt', '" + e + "c8'), ('cdbl', '" + e + "c16')]",
     ]
 
-    d1 = np.dtype({'names': ['a', 'b'], 'formats': ['int32', 'float64'],
-                   'offsets': [1, 10], 'itemsize': 20})
-    d2 = np.dtype([('a', 'i4'), ('b', 'f4')])
-    assert m.test_dtype_ctors() == [np.dtype('int32'), np.dtype('float64'),
-                                    np.dtype('bool'), d1, d1, np.dtype('uint32'), d2]
+    d1 = np.dtype(
+        {
+            "names": ["a", "b"],
+            "formats": ["int32", "float64"],
+            "offsets": [1, 10],
+            "itemsize": 20,
+        }
+    )
+    d2 = np.dtype([("a", "i4"), ("b", "f4")])
+    assert m.test_dtype_ctors() == [
+        np.dtype("int32"),
+        np.dtype("float64"),
+        np.dtype("bool"),
+        d1,
+        d1,
+        np.dtype("uint32"),
+        d2,
+    ]
 
-    assert m.test_dtype_methods() == [np.dtype('int32'), simple_dtype, False, True,
-                                      np.dtype('int32').itemsize, simple_dtype.itemsize]
+    assert m.test_dtype_methods() == [
+        np.dtype("int32"),
+        simple_dtype,
+        False,
+        True,
+        np.dtype("int32").itemsize,
+        simple_dtype.itemsize,
+    ]
 
-    assert m.trailing_padding_dtype() == m.buffer_to_dtype(np.zeros(1, m.trailing_padding_dtype()))
+    assert m.trailing_padding_dtype() == m.buffer_to_dtype(
+        np.zeros(1, m.trailing_padding_dtype())
+    )
 
 
 def test_recarray(simple_dtype, packed_dtype):
     elements = [(False, 0, 0.0, -0.0), (True, 1, 1.5, -2.5), (False, 2, 3.0, -5.0)]
 
-    for func, dtype in [(m.create_rec_simple, simple_dtype), (m.create_rec_packed, packed_dtype)]:
+    for func, dtype in [
+        (m.create_rec_simple, simple_dtype),
+        (m.create_rec_packed, packed_dtype),
+    ]:
         arr = func(0)
         assert arr.dtype == dtype
         assert_equal(arr, [], simple_dtype)
@@ -146,16 +195,16 @@ def test_recarray(simple_dtype, packed_dtype):
             assert m.print_rec_simple(arr) == [
                 "s:0,0,0,-0",
                 "s:1,1,1.5,-2.5",
-                "s:0,2,3,-5"
+                "s:0,2,3,-5",
             ]
         else:
             assert m.print_rec_packed(arr) == [
                 "p:0,0,0,-0",
                 "p:1,1,1.5,-2.5",
-                "p:0,2,3,-5"
+                "p:0,2,3,-5",
             ]
 
-    nested_dtype = np.dtype([('a', simple_dtype), ('b', packed_dtype)])
+    nested_dtype = np.dtype([("a", simple_dtype), ("b", packed_dtype)])
 
     arr = m.create_rec_nested(0)
     assert arr.dtype == nested_dtype
@@ -163,33 +212,39 @@ def test_recarray(simple_dtype, packed_dtype):
 
     arr = m.create_rec_nested(3)
     assert arr.dtype == nested_dtype
-    assert_equal(arr, [((False, 0, 0.0, -0.0), (True, 1, 1.5, -2.5)),
+    assert_equal(
+        arr,
+        [
+            ((False, 0, 0.0, -0.0), (True, 1, 1.5, -2.5)),
             ((True, 1, 1.5, -2.5), (False, 2, 3.0, -5.0)),
-                       ((False, 2, 3.0, -5.0), (True, 3, 4.5, -7.5))], nested_dtype)
+            ((False, 2, 3.0, -5.0), (True, 3, 4.5, -7.5)),
+        ],
+        nested_dtype,
+    )
     assert m.print_rec_nested(arr) == [
         "n:a=s:0,0,0,-0;b=p:1,1,1.5,-2.5",
         "n:a=s:1,1,1.5,-2.5;b=p:0,2,3,-5",
-        "n:a=s:0,2,3,-5;b=p:1,3,4.5,-7.5"
+        "n:a=s:0,2,3,-5;b=p:1,3,4.5,-7.5",
     ]
 
     arr = m.create_rec_partial(3)
     assert str(arr.dtype) == partial_dtype_fmt()
     partial_dtype = arr.dtype
-    assert '' not in arr.dtype.fields
+    assert "" not in arr.dtype.fields
     assert partial_dtype.itemsize > simple_dtype.itemsize
     assert_equal(arr, elements, simple_dtype)
     assert_equal(arr, elements, packed_dtype)
 
     arr = m.create_rec_partial_nested(3)
     assert str(arr.dtype) == partial_nested_fmt()
-    assert '' not in arr.dtype.fields
-    assert '' not in arr.dtype.fields['a'][0].fields
+    assert "" not in arr.dtype.fields
+    assert "" not in arr.dtype.fields["a"][0].fields
     assert arr.dtype.itemsize > partial_dtype.itemsize
-    np.testing.assert_equal(arr['a'], m.create_rec_partial(3))
+    np.testing.assert_equal(arr["a"], m.create_rec_partial(3))
 
 
 def test_array_constructors():
-    data = np.arange(1, 7, dtype='int32')
+    data = np.arange(1, 7, dtype="int32")
     for i in range(8):
         np.testing.assert_array_equal(m.test_array_ctors(10 + i), data.reshape((3, 2)))
         np.testing.assert_array_equal(m.test_array_ctors(20 + i), data.reshape((3, 2)))
@@ -205,82 +260,92 @@ def test_string_array():
         "a='',b=''",
         "a='a',b='a'",
         "a='ab',b='ab'",
-        "a='abc',b='abc'"
+        "a='abc',b='abc'",
     ]
     dtype = arr.dtype
-    assert arr['a'].tolist() == [b'', b'a', b'ab', b'abc']
-    assert arr['b'].tolist() == [b'', b'a', b'ab', b'abc']
+    assert arr["a"].tolist() == [b"", b"a", b"ab", b"abc"]
+    assert arr["b"].tolist() == [b"", b"a", b"ab", b"abc"]
     arr = m.create_string_array(False)
     assert dtype == arr.dtype
 
 
 def test_array_array():
     from sys import byteorder
-    e = '<' if byteorder == 'little' else '>'
+
+    e = "<" if byteorder == "little" else ">"
 
     arr = m.create_array_array(3)
     assert str(arr.dtype) == (
-        "{{'names':['a','b','c','d'], " +
-        "'formats':[('S4', (3,)),('" + e + "i4', (2,)),('u1', (3,)),('{e}f4', (4, 2))], " +
-        "'offsets':[0,12,20,24], 'itemsize':56}}").format(e=e)
+        "{{'names':['a','b','c','d'], "
+        + "'formats':[('S4', (3,)),('"
+        + e
+        + "i4', (2,)),('u1', (3,)),('{e}f4', (4, 2))], "
+        + "'offsets':[0,12,20,24], 'itemsize':56}}"
+    ).format(e=e)
     assert m.print_array_array(arr) == [
-        "a={{A,B,C,D},{K,L,M,N},{U,V,W,X}},b={0,1}," +
-        "c={0,1,2},d={{0,1},{10,11},{20,21},{30,31}}",
-        "a={{W,X,Y,Z},{G,H,I,J},{Q,R,S,T}},b={1000,1001}," +
-        "c={10,11,12},d={{100,101},{110,111},{120,121},{130,131}}",
-        "a={{S,T,U,V},{C,D,E,F},{M,N,O,P}},b={2000,2001}," +
-        "c={20,21,22},d={{200,201},{210,211},{220,221},{230,231}}",
+        "a={{A,B,C,D},{K,L,M,N},{U,V,W,X}},b={0,1},"
+        + "c={0,1,2},d={{0,1},{10,11},{20,21},{30,31}}",
+        "a={{W,X,Y,Z},{G,H,I,J},{Q,R,S,T}},b={1000,1001},"
+        + "c={10,11,12},d={{100,101},{110,111},{120,121},{130,131}}",
+        "a={{S,T,U,V},{C,D,E,F},{M,N,O,P}},b={2000,2001},"
+        + "c={20,21,22},d={{200,201},{210,211},{220,221},{230,231}}",
     ]
-    assert arr['a'].tolist() == [[b'ABCD', b'KLMN', b'UVWX'],
-                                 [b'WXYZ', b'GHIJ', b'QRST'],
-                                 [b'STUV', b'CDEF', b'MNOP']]
-    assert arr['b'].tolist() == [[0, 1], [1000, 1001], [2000, 2001]]
+    assert arr["a"].tolist() == [
+        [b"ABCD", b"KLMN", b"UVWX"],
+        [b"WXYZ", b"GHIJ", b"QRST"],
+        [b"STUV", b"CDEF", b"MNOP"],
+    ]
+    assert arr["b"].tolist() == [[0, 1], [1000, 1001], [2000, 2001]]
     assert m.create_array_array(0).dtype == arr.dtype
 
 
 def test_enum_array():
     from sys import byteorder
-    e = '<' if byteorder == 'little' else '>'
+
+    e = "<" if byteorder == "little" else ">"
 
     arr = m.create_enum_array(3)
     dtype = arr.dtype
-    assert dtype == np.dtype([('e1', e + 'i8'), ('e2', 'u1')])
-    assert m.print_enum_array(arr) == [
-        "e1=A,e2=X",
-        "e1=B,e2=Y",
-        "e1=A,e2=X"
-    ]
-    assert arr['e1'].tolist() == [-1, 1, -1]
-    assert arr['e2'].tolist() == [1, 2, 1]
+    assert dtype == np.dtype([("e1", e + "i8"), ("e2", "u1")])
+    assert m.print_enum_array(arr) == ["e1=A,e2=X", "e1=B,e2=Y", "e1=A,e2=X"]
+    assert arr["e1"].tolist() == [-1, 1, -1]
+    assert arr["e2"].tolist() == [1, 2, 1]
     assert m.create_enum_array(0).dtype == dtype
 
 
 def test_complex_array():
     from sys import byteorder
-    e = '<' if byteorder == 'little' else '>'
+
+    e = "<" if byteorder == "little" else ">"
 
     arr = m.create_complex_array(3)
     dtype = arr.dtype
-    assert dtype == np.dtype([('cflt', e + 'c8'), ('cdbl', e + 'c16')])
+    assert dtype == np.dtype([("cflt", e + "c8"), ("cdbl", e + "c16")])
     assert m.print_complex_array(arr) == [
         "c:(0,0.25),(0.5,0.75)",
         "c:(1,1.25),(1.5,1.75)",
-        "c:(2,2.25),(2.5,2.75)"
+        "c:(2,2.25),(2.5,2.75)",
     ]
-    assert arr['cflt'].tolist() == [0.0 + 0.25j, 1.0 + 1.25j, 2.0 + 2.25j]
-    assert arr['cdbl'].tolist() == [0.5 + 0.75j, 1.5 + 1.75j, 2.5 + 2.75j]
+    assert arr["cflt"].tolist() == [0.0 + 0.25j, 1.0 + 1.25j, 2.0 + 2.25j]
+    assert arr["cdbl"].tolist() == [0.5 + 0.75j, 1.5 + 1.75j, 2.5 + 2.75j]
     assert m.create_complex_array(0).dtype == dtype
 
 
 def test_signature(doc):
-    assert doc(m.create_rec_nested) == \
-        "create_rec_nested(arg0: int) -> numpy.ndarray[NestedStruct]"
+    assert (
+        doc(m.create_rec_nested)
+        == "create_rec_nested(arg0: int) -> numpy.ndarray[NestedStruct]"
+    )
 
 
 def test_scalar_conversion():
     n = 3
-    arrays = [m.create_rec_simple(n), m.create_rec_packed(n),
-              m.create_rec_nested(n), m.create_enum_array(n)]
+    arrays = [
+        m.create_rec_simple(n),
+        m.create_rec_packed(n),
+        m.create_rec_nested(n),
+        m.create_enum_array(n),
+    ]
     funcs = [m.f_simple, m.f_packed, m.f_nested]
 
     for i, func in enumerate(funcs):
@@ -290,7 +355,7 @@ def test_scalar_conversion():
             else:
                 with pytest.raises(TypeError) as excinfo:
                     func(arr[0])
-                assert 'incompatible function arguments' in str(excinfo.value)
+                assert "incompatible function arguments" in str(excinfo.value)
 
 
 def test_vectorize():
@@ -304,14 +369,14 @@ def test_vectorize():
 
 def test_cls_and_dtype_conversion(simple_dtype):
     s = m.SimpleStruct()
-    assert s.astuple() == (False, 0, 0., 0.)
+    assert s.astuple() == (False, 0, 0.0, 0.0)
     assert m.SimpleStruct.fromtuple(s.astuple()).astuple() == s.astuple()
 
     s.uint_ = 2
     assert m.f_simple(s) == 20
 
     # Try as recarray of shape==(1,).
-    s_recarray = np.array([(False, 2, 0., 0.)], dtype=simple_dtype)
+    s_recarray = np.array([(False, 2, 0.0, 0.0)], dtype=simple_dtype)
     # Show that this will work for vectorized case.
     np.testing.assert_array_equal(m.f_simple_vectorized(s_recarray), [20])
 
@@ -327,17 +392,16 @@ def test_cls_and_dtype_conversion(simple_dtype):
     assert s_recarray_scalar.dtype == simple_dtype
     with pytest.raises(TypeError) as excinfo:
         m.f_simple(s_recarray_scalar)
-    assert 'incompatible function arguments' in str(excinfo.value)
+    assert "incompatible function arguments" in str(excinfo.value)
     # Explicitly convert to m.SimpleStruct.
-    assert m.f_simple(
-        m.SimpleStruct.fromtuple(s_recarray_scalar.item())) == 20
+    assert m.f_simple(m.SimpleStruct.fromtuple(s_recarray_scalar.item())) == 20
 
     # Show that an array of dtype=object does *not* convert.
     s_array_object = np.array([s])
     assert s_array_object.dtype == object
     with pytest.raises(TypeError) as excinfo:
         m.f_simple_vectorized(s_array_object)
-    assert 'incompatible function arguments' in str(excinfo.value)
+    assert "incompatible function arguments" in str(excinfo.value)
     # Explicitly convert to `np.array(..., dtype=simple_dtype)`
     s_array = np.array([s.astuple()], dtype=simple_dtype)
     np.testing.assert_array_equal(m.f_simple_vectorized(s_array), [20])
@@ -346,12 +410,13 @@ def test_cls_and_dtype_conversion(simple_dtype):
 def test_register_dtype():
     with pytest.raises(RuntimeError) as excinfo:
         m.register_dtype()
-    assert 'dtype is already registered' in str(excinfo.value)
+    assert "dtype is already registered" in str(excinfo.value)
 
 
 @pytest.mark.xfail("env.PYPY")
 def test_str_leak():
     from sys import getrefcount
+
     fmt = "f4"
     pytest.gc_collect()
     start = getrefcount(fmt)

tests/test_numpy_vectorize.py

@@ -17,28 +17,40 @@ def test_vectorize(capture):
         assert capture == "my_func(x:int=1, y:float=2, z:float=3)"
         with capture:
             assert np.allclose(f(np.array([1, 3]), np.array([2, 4]), 3), [6, 36])
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=2, z:float=3)
             my_func(x:int=3, y:float=4, z:float=3)
         """
+        )
         with capture:
-            a = np.array([[1, 2], [3, 4]], order='F')
-            b = np.array([[10, 20], [30, 40]], order='F')
+            a = np.array([[1, 2], [3, 4]], order="F")
+            b = np.array([[10, 20], [30, 40]], order="F")
             c = 3
             result = f(a, b, c)
             assert np.allclose(result, a * b * c)
             assert result.flags.f_contiguous
         # All inputs are F order and full or singletons, so we the result is in col-major order:
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=10, z:float=3)
             my_func(x:int=3, y:float=30, z:float=3)
             my_func(x:int=2, y:float=20, z:float=3)
             my_func(x:int=4, y:float=40, z:float=3)
         """
+        )
         with capture:
-            a, b, c = np.array([[1, 3, 5], [7, 9, 11]]), np.array([[2, 4, 6], [8, 10, 12]]), 3
+            a, b, c = (
+                np.array([[1, 3, 5], [7, 9, 11]]),
+                np.array([[2, 4, 6], [8, 10, 12]]),
+                3,
+            )
             assert np.allclose(f(a, b, c), a * b * c)
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=2, z:float=3)
             my_func(x:int=3, y:float=4, z:float=3)
             my_func(x:int=5, y:float=6, z:float=3)
@@ -46,10 +58,13 @@ def test_vectorize(capture):
             my_func(x:int=9, y:float=10, z:float=3)
             my_func(x:int=11, y:float=12, z:float=3)
         """
+        )
         with capture:
             a, b, c = np.array([[1, 2, 3], [4, 5, 6]]), np.array([2, 3, 4]), 2
             assert np.allclose(f(a, b, c), a * b * c)
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=2, z:float=2)
             my_func(x:int=2, y:float=3, z:float=2)
             my_func(x:int=3, y:float=4, z:float=2)
@@ -57,10 +72,13 @@ def test_vectorize(capture):
             my_func(x:int=5, y:float=3, z:float=2)
             my_func(x:int=6, y:float=4, z:float=2)
         """
+        )
         with capture:
             a, b, c = np.array([[1, 2, 3], [4, 5, 6]]), np.array([[2], [3]]), 2
             assert np.allclose(f(a, b, c), a * b * c)
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=2, z:float=2)
             my_func(x:int=2, y:float=2, z:float=2)
             my_func(x:int=3, y:float=2, z:float=2)
@@ -68,10 +86,17 @@ def test_vectorize(capture):
             my_func(x:int=5, y:float=3, z:float=2)
             my_func(x:int=6, y:float=3, z:float=2)
         """
+        )
         with capture:
-            a, b, c = np.array([[1, 2, 3], [4, 5, 6]], order='F'), np.array([[2], [3]]), 2
+            a, b, c = (
+                np.array([[1, 2, 3], [4, 5, 6]], order="F"),
+                np.array([[2], [3]]),
+                2,
+            )
             assert np.allclose(f(a, b, c), a * b * c)
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=2, z:float=2)
             my_func(x:int=2, y:float=2, z:float=2)
             my_func(x:int=3, y:float=2, z:float=2)
@@ -79,36 +104,53 @@ def test_vectorize(capture):
             my_func(x:int=5, y:float=3, z:float=2)
             my_func(x:int=6, y:float=3, z:float=2)
         """
+        )
         with capture:
             a, b, c = np.array([[1, 2, 3], [4, 5, 6]])[::, ::2], np.array([[2], [3]]), 2
             assert np.allclose(f(a, b, c), a * b * c)
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=2, z:float=2)
             my_func(x:int=3, y:float=2, z:float=2)
             my_func(x:int=4, y:float=3, z:float=2)
             my_func(x:int=6, y:float=3, z:float=2)
         """
+        )
         with capture:
-            a, b, c = np.array([[1, 2, 3], [4, 5, 6]], order='F')[::, ::2], np.array([[2], [3]]), 2
+            a, b, c = (
+                np.array([[1, 2, 3], [4, 5, 6]], order="F")[::, ::2],
+                np.array([[2], [3]]),
+                2,
+            )
             assert np.allclose(f(a, b, c), a * b * c)
-        assert capture == """
+        assert (
+            capture
+            == """
             my_func(x:int=1, y:float=2, z:float=2)
             my_func(x:int=3, y:float=2, z:float=2)
             my_func(x:int=4, y:float=3, z:float=2)
             my_func(x:int=6, y:float=3, z:float=2)
         """
+        )
 
 
 def test_type_selection():
     assert m.selective_func(np.array([1], dtype=np.int32)) == "Int branch taken."
     assert m.selective_func(np.array([1.0], dtype=np.float32)) == "Float branch taken."
-    assert m.selective_func(np.array([1.0j], dtype=np.complex64)) == "Complex float branch taken."
+    assert (
+        m.selective_func(np.array([1.0j], dtype=np.complex64))
+        == "Complex float branch taken."
+    )
 
 
 def test_docs(doc):
-    assert doc(m.vectorized_func) == """
+    assert (
+        doc(m.vectorized_func)
+        == """
         vectorized_func(arg0: numpy.ndarray[numpy.int32], arg1: numpy.ndarray[numpy.float32], arg2: numpy.ndarray[numpy.float64]) -> object
     """  # noqa: E501 line too long
+    )
 
 
 def test_trivial_broadcasting():
@@ -116,16 +158,24 @@ def test_trivial_broadcasting():
 
     assert vectorized_is_trivial(1, 2, 3) == trivial.c_trivial
     assert vectorized_is_trivial(np.array(1), np.array(2), 3) == trivial.c_trivial
-    assert vectorized_is_trivial(np.array([1, 3]), np.array([2, 4]), 3) == trivial.c_trivial
+    assert (
+        vectorized_is_trivial(np.array([1, 3]), np.array([2, 4]), 3)
+        == trivial.c_trivial
+    )
     assert trivial.c_trivial == vectorized_is_trivial(
-        np.array([[1, 3, 5], [7, 9, 11]]), np.array([[2, 4, 6], [8, 10, 12]]), 3)
-    assert vectorized_is_trivial(
-        np.array([[1, 2, 3], [4, 5, 6]]), np.array([2, 3, 4]), 2) == trivial.non_trivial
-    assert vectorized_is_trivial(
-        np.array([[1, 2, 3], [4, 5, 6]]), np.array([[2], [3]]), 2) == trivial.non_trivial
-    z1 = np.array([[1, 2, 3, 4], [5, 6, 7, 8]], dtype='int32')
-    z2 = np.array(z1, dtype='float32')
-    z3 = np.array(z1, dtype='float64')
+        np.array([[1, 3, 5], [7, 9, 11]]), np.array([[2, 4, 6], [8, 10, 12]]), 3
+    )
+    assert (
+        vectorized_is_trivial(np.array([[1, 2, 3], [4, 5, 6]]), np.array([2, 3, 4]), 2)
+        == trivial.non_trivial
+    )
+    assert (
+        vectorized_is_trivial(np.array([[1, 2, 3], [4, 5, 6]]), np.array([[2], [3]]), 2)
+        == trivial.non_trivial
+    )
+    z1 = np.array([[1, 2, 3, 4], [5, 6, 7, 8]], dtype="int32")
+    z2 = np.array(z1, dtype="float32")
+    z3 = np.array(z1, dtype="float64")
     assert vectorized_is_trivial(z1, z2, z3) == trivial.c_trivial
     assert vectorized_is_trivial(1, z2, z3) == trivial.c_trivial
     assert vectorized_is_trivial(z1, 1, z3) == trivial.c_trivial
@@ -135,7 +185,7 @@ def test_trivial_broadcasting():
     assert vectorized_is_trivial(1, 1, z3[::2, ::2]) == trivial.non_trivial
     assert vectorized_is_trivial(z1, 1, z3[1::4, 1::4]) == trivial.c_trivial
 
-    y1 = np.array(z1, order='F')
+    y1 = np.array(z1, order="F")
     y2 = np.array(y1)
     y3 = np.array(y1)
     assert vectorized_is_trivial(y1, y2, y3) == trivial.f_trivial
@@ -156,30 +206,41 @@ def test_trivial_broadcasting():
 
 def test_passthrough_arguments(doc):
     assert doc(m.vec_passthrough) == (
-        "vec_passthrough(" + ", ".join([
+        "vec_passthrough("
+        + ", ".join(
+            [
                 "arg0: float",
                 "arg1: numpy.ndarray[numpy.float64]",
                 "arg2: numpy.ndarray[numpy.float64]",
                 "arg3: numpy.ndarray[numpy.int32]",
                 "arg4: int",
                 "arg5: m.numpy_vectorize.NonPODClass",
-            "arg6: numpy.ndarray[numpy.float64]"]) + ") -> object")
+                "arg6: numpy.ndarray[numpy.float64]",
+            ]
+        )
+        + ") -> object"
+    )
 
-    b = np.array([[10, 20, 30]], dtype='float64')
+    b = np.array([[10, 20, 30]], dtype="float64")
     c = np.array([100, 200])  # NOT a vectorized argument
-    d = np.array([[1000], [2000], [3000]], dtype='int')
-    g = np.array([[1000000, 2000000, 3000000]], dtype='int')  # requires casting
+    d = np.array([[1000], [2000], [3000]], dtype="int")
+    g = np.array([[1000000, 2000000, 3000000]], dtype="int")  # requires casting
     assert np.all(
-        m.vec_passthrough(1, b, c, d, 10000, m.NonPODClass(100000), g) ==
-        np.array([[1111111, 2111121, 3111131],
+        m.vec_passthrough(1, b, c, d, 10000, m.NonPODClass(100000), g)
+        == np.array(
+            [
+                [1111111, 2111121, 3111131],
                 [1112111, 2112121, 3112131],
-                  [1113111, 2113121, 3113131]]))
+                [1113111, 2113121, 3113131],
+            ]
+        )
+    )
 
 
 def test_method_vectorization():
     o = m.VectorizeTestClass(3)
-    x = np.array([1, 2], dtype='int')
-    y = np.array([[10], [20]], dtype='float32')
+    x = np.array([1, 2], dtype="int")
+    y = np.array([[10], [20]], dtype="float32")
     assert np.all(o.method(x, y) == [[14, 15], [24, 25]])
 
 
@@ -188,7 +249,7 @@ def test_array_collapse():
     assert not isinstance(m.vectorized_func(np.array(1), 2, 3), np.ndarray)
     z = m.vectorized_func([1], 2, 3)
     assert isinstance(z, np.ndarray)
-    assert z.shape == (1, )
+    assert z.shape == (1,)
     z = m.vectorized_func(1, [[[2]]], 3)
     assert isinstance(z, np.ndarray)
     assert z.shape == (1, 1, 1)

tests/test_opaque_types.py

@@ -32,12 +32,15 @@ def test_pointers(msg):
 
     with pytest.raises(TypeError) as excinfo:
         m.get_void_ptr_value([1, 2, 3])  # This should not work
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         get_void_ptr_value(): incompatible function arguments. The following argument types are supported:
             1. (arg0: capsule) -> int
 
         Invoked with: [1, 2, 3]
     """  # noqa: E501 line too long
+    )
 
     assert m.return_null_str() is None
     assert m.get_null_str_value(m.return_null_str()) is not None

tests/test_operator_overloading.py

@@ -56,23 +56,23 @@ def test_operator_overloading():
     del v3
     assert cstats.alive() == 0
     assert cstats.values() == [
-        '[1.000000, 2.000000]',
-        '[3.000000, -1.000000]',
-        '[1.000000, 2.000000]',
-        '[-3.000000, 1.000000]',
-        '[4.000000, 1.000000]',
-        '[-2.000000, 3.000000]',
-        '[-7.000000, -6.000000]',
-        '[9.000000, 10.000000]',
-        '[8.000000, 16.000000]',
-        '[0.125000, 0.250000]',
-        '[7.000000, 6.000000]',
-        '[9.000000, 10.000000]',
-        '[8.000000, 16.000000]',
-        '[8.000000, 4.000000]',
-        '[3.000000, -2.000000]',
-        '[3.000000, -0.500000]',
-        '[6.000000, -2.000000]',
+        "[1.000000, 2.000000]",
+        "[3.000000, -1.000000]",
+        "[1.000000, 2.000000]",
+        "[-3.000000, 1.000000]",
+        "[4.000000, 1.000000]",
+        "[-2.000000, 3.000000]",
+        "[-7.000000, -6.000000]",
+        "[9.000000, 10.000000]",
+        "[8.000000, 16.000000]",
+        "[0.125000, 0.250000]",
+        "[7.000000, 6.000000]",
+        "[9.000000, 10.000000]",
+        "[8.000000, 16.000000]",
+        "[8.000000, 4.000000]",
+        "[3.000000, -2.000000]",
+        "[3.000000, -0.500000]",
+        "[6.000000, -2.000000]",
     ]
     assert cstats.default_constructions == 0
     assert cstats.copy_constructions == 0

tests/test_pickling.py

@@ -42,5 +42,6 @@ def test_roundtrip_with_dict(cls_name):
 
 def test_enum_pickle():
     from pybind11_tests import enums as e
+
     data = pickle.dumps(e.EOne, 2)
     assert e.EOne == pickle.loads(data)

tests/test_pytypes.py

@@ -28,13 +28,16 @@ def test_list(capture, doc):
 
         lst.append("value2")
         m.print_list(lst)
-    assert capture.unordered == """
+    assert (
+        capture.unordered
+        == """
         Entry at position 0: value
         list item 0: inserted-0
         list item 1: overwritten
         list item 2: inserted-2
         list item 3: value2
     """
+    )
 
     assert doc(m.get_list) == "get_list() -> list"
     assert doc(m.print_list) == "print_list(arg0: list) -> None"
@@ -52,12 +55,15 @@ def test_set(capture, doc):
     with capture:
         s.add("key4")
         m.print_set(s)
-    assert capture.unordered == """
+    assert (
+        capture.unordered
+        == """
         key: key1
         key: key2
         key: key3
         key: key4
     """
+    )
 
     assert not m.set_contains(set([]), 42)
     assert m.set_contains({42}, 42)
@@ -74,10 +80,13 @@ def test_dict(capture, doc):
     with capture:
         d["key2"] = "value2"
         m.print_dict(d)
-    assert capture.unordered == """
+    assert (
+        capture.unordered
+        == """
         key: key, value=value
         key: key2, value=value2
     """
+    )
 
     assert not m.dict_contains({}, 42)
     assert m.dict_contains({42: None}, 42)
@@ -137,28 +146,37 @@ def test_capsule(capture):
         a = m.return_capsule_with_destructor()
         del a
         pytest.gc_collect()
-    assert capture.unordered == """
+    assert (
+        capture.unordered
+        == """
         creating capsule
         destructing capsule
     """
+    )
 
     with capture:
         a = m.return_capsule_with_destructor_2()
         del a
         pytest.gc_collect()
-    assert capture.unordered == """
+    assert (
+        capture.unordered
+        == """
         creating capsule
         destructing capsule: 1234
     """
+    )
 
     with capture:
         a = m.return_capsule_with_name_and_destructor()
         del a
         pytest.gc_collect()
-    assert capture.unordered == """
+    assert (
+        capture.unordered
+        == """
         created capsule (1234, 'pointer type description')
         destructing capsule (1234, 'pointer type description')
     """
+    )
 
 
 def test_accessors():
@@ -212,7 +230,7 @@ def test_constructors():
     assert m.default_constructors() == expected
 
     data = {
-        bytes: b'41',  # Currently no supported or working conversions.
+        bytes: b"41",  # Currently no supported or working conversions.
         str: 42,
         bool: "Not empty",
         int: "42",
@@ -221,14 +239,14 @@ def test_constructors():
         list: range(3),
         dict: [("two", 2), ("one", 1), ("three", 3)],
         set: [4, 4, 5, 6, 6, 6],
-        memoryview: b'abc'
+        memoryview: b"abc",
     }
     inputs = {k.__name__: v for k, v in data.items()}
     expected = {k.__name__: k(v) for k, v in data.items()}
     if env.PY2:  # Similar to the above. See comments above.
-        inputs["bytes"] = b'41'
+        inputs["bytes"] = b"41"
         inputs["str"] = 42
-        expected["bytes"] = b'41'
+        expected["bytes"] = b"41"
         expected["str"] = u"42"
 
     assert m.converting_constructors(inputs) == expected
@@ -255,7 +273,8 @@ def test_non_converting_constructors():
         with pytest.raises(TypeError) as excinfo:
             m.nonconverting_constructor(t, v)
         expected_error = "Object of type '{}' is not an instance of '{}'".format(
-            type(v).__name__, t)
+            type(v).__name__, t
+        )
         assert str(excinfo.value) == expected_error
 
 
@@ -263,12 +282,12 @@ def test_pybind11_str_raw_str():
     # specifically to exercise pybind11::str::raw_str
     cvt = m.convert_to_pybind11_str
     assert cvt(u"Str") == u"Str"
-    assert cvt(b'Bytes') == u"Bytes" if env.PY2 else "b'Bytes'"
+    assert cvt(b"Bytes") == u"Bytes" if env.PY2 else "b'Bytes'"
     assert cvt(None) == u"None"
     assert cvt(False) == u"False"
     assert cvt(True) == u"True"
     assert cvt(42) == u"42"
-    assert cvt(2**65) == u"36893488147419103232"
+    assert cvt(2 ** 65) == u"36893488147419103232"
     assert cvt(-1.50) == u"-1.5"
     assert cvt(()) == u"()"
     assert cvt((18,)) == u"(18,)"
@@ -283,29 +302,40 @@ def test_pybind11_str_raw_str():
     valid_utf8 = valid_orig.encode("utf-8")
     valid_cvt = cvt(valid_utf8)
     assert type(valid_cvt) == bytes  # Probably surprising.
-    assert valid_cvt == b'\xc7\xb1'
+    assert valid_cvt == b"\xc7\xb1"
 
-    malformed_utf8 = b'\x80'
+    malformed_utf8 = b"\x80"
     malformed_cvt = cvt(malformed_utf8)
     assert type(malformed_cvt) == bytes  # Probably surprising.
-    assert malformed_cvt == b'\x80'
+    assert malformed_cvt == b"\x80"
 
 
 def test_implicit_casting():
     """Tests implicit casting when assigning or appending to dicts and lists."""
     z = m.get_implicit_casting()
-    assert z['d'] == {
-        'char*_i1': 'abc', 'char*_i2': 'abc', 'char*_e': 'abc', 'char*_p': 'abc',
-        'str_i1': 'str', 'str_i2': 'str1', 'str_e': 'str2', 'str_p': 'str3',
-        'int_i1': 42, 'int_i2': 42, 'int_e': 43, 'int_p': 44
+    assert z["d"] == {
+        "char*_i1": "abc",
+        "char*_i2": "abc",
+        "char*_e": "abc",
+        "char*_p": "abc",
+        "str_i1": "str",
+        "str_i2": "str1",
+        "str_e": "str2",
+        "str_p": "str3",
+        "int_i1": 42,
+        "int_i2": 42,
+        "int_e": 43,
+        "int_p": 44,
     }
-    assert z['l'] == [3, 6, 9, 12, 15]
+    assert z["l"] == [3, 6, 9, 12, 15]
 
 
 def test_print(capture):
     with capture:
         m.print_function()
-    assert capture == """
+    assert (
+        capture
+        == """
         Hello, World!
         1 2.0 three True -- multiple args
         *args-and-a-custom-separator
@@ -313,14 +343,15 @@ def test_print(capture):
         flush
         py::print + str.format = this
     """
+    )
     assert capture.stderr == "this goes to stderr"
 
     with pytest.raises(RuntimeError) as excinfo:
         m.print_failure()
     assert str(excinfo.value) == "make_tuple(): unable to convert " + (
         "argument of type 'UnregisteredType' to Python object"
-        if debug_enabled else
-        "arguments to Python object (compile in debug mode for details)"
+        if debug_enabled
+        else "arguments to Python object (compile in debug mode for details)"
     )
 
 
@@ -342,8 +373,23 @@ def test_hash():
 
 def test_number_protocol():
     for a, b in [(1, 1), (3, 5)]:
-        li = [a == b, a != b, a < b, a <= b, a > b, a >= b, a + b,
-              a - b, a * b, a / b, a | b, a & b, a ^ b, a >> b, a << b]
+        li = [
+            a == b,
+            a != b,
+            a < b,
+            a <= b,
+            a > b,
+            a >= b,
+            a + b,
+            a - b,
+            a * b,
+            a / b,
+            a | b,
+            a & b,
+            a ^ b,
+            a >> b,
+            a << b,
+        ]
         assert m.test_number_protocol(a, b) == li
 
 
@@ -360,13 +406,16 @@ def test_issue2361():
     assert "'NoneType' object is not iterable" in str(excinfo.value)
 
 
-@pytest.mark.parametrize('method, args, fmt, expected_view', [
-    (m.test_memoryview_object, (b'red',), 'B', b'red'),
-    (m.test_memoryview_buffer_info, (b'green',), 'B', b'green'),
-    (m.test_memoryview_from_buffer, (False,), 'h', [3, 1, 4, 1, 5]),
-    (m.test_memoryview_from_buffer, (True,), 'H', [2, 7, 1, 8]),
-    (m.test_memoryview_from_buffer_nativeformat, (), '@i', [4, 7, 5]),
-])
+@pytest.mark.parametrize(
+    "method, args, fmt, expected_view",
+    [
+        (m.test_memoryview_object, (b"red",), "B", b"red"),
+        (m.test_memoryview_buffer_info, (b"green",), "B", b"green"),
+        (m.test_memoryview_from_buffer, (False,), "h", [3, 1, 4, 1, 5]),
+        (m.test_memoryview_from_buffer, (True,), "H", [2, 7, 1, 8]),
+        (m.test_memoryview_from_buffer_nativeformat, (), "@i", [4, 7, 5]),
+    ],
+)
 def test_memoryview(method, args, fmt, expected_view):
     view = method(*args)
     assert isinstance(view, memoryview)
@@ -380,12 +429,15 @@ def test_memoryview(method, args, fmt, expected_view):
 
 
 @pytest.mark.xfail("env.PYPY", reason="getrefcount is not available")
-@pytest.mark.parametrize('method', [
+@pytest.mark.parametrize(
+    "method",
+    [
         m.test_memoryview_object,
         m.test_memoryview_buffer_info,
-])
+    ],
+)
 def test_memoryview_refcount(method):
-    buf = b'\x0a\x0b\x0c\x0d'
+    buf = b"\x0a\x0b\x0c\x0d"
     ref_before = sys.getrefcount(buf)
     view = method(buf)
     ref_after = sys.getrefcount(buf)
@@ -396,13 +448,13 @@ def test_memoryview_refcount(method):
 def test_memoryview_from_buffer_empty_shape():
     view = m.test_memoryview_from_buffer_empty_shape()
     assert isinstance(view, memoryview)
-    assert view.format == 'B'
+    assert view.format == "B"
     if env.PY2:
         # Python 2 behavior is weird, but Python 3 (the future) is fine.
         # PyPy3 has <memoryview, while CPython 2 has <memory
-        assert bytes(view).startswith(b'<memory')
+        assert bytes(view).startswith(b"<memory")
     else:
-        assert bytes(view) == b''
+        assert bytes(view) == b""
 
 
 def test_test_memoryview_from_buffer_invalid_strides():
@@ -422,13 +474,15 @@ def test_test_memoryview_from_buffer_nullptr():
 def test_memoryview_from_memory():
     view = m.test_memoryview_from_memory()
     assert isinstance(view, memoryview)
-    assert view.format == 'B'
-    assert bytes(view) == b'\xff\xe1\xab\x37'
+    assert view.format == "B"
+    assert bytes(view) == b"\xff\xe1\xab\x37"
 
 
 def test_builtin_functions():
     assert m.get_len([i for i in range(42)]) == 42
     with pytest.raises(TypeError) as exc_info:
         m.get_len(i for i in range(42))
-    assert str(exc_info.value) in ["object of type 'generator' has no len()",
-                                   "'generator' has no length"]  # PyPy
+    assert str(exc_info.value) in [
+        "object of type 'generator' has no len()",
+        "'generator' has no length",
+    ]  # PyPy

tests/test_sequences_and_iterators.py

@@ -10,7 +10,9 @@ def isclose(a, b, rel_tol=1e-05, abs_tol=0.0):
 
 
 def allclose(a_list, b_list, rel_tol=1e-05, abs_tol=0.0):
-    return all(isclose(a, b, rel_tol=rel_tol, abs_tol=abs_tol) for a, b in zip(a_list, b_list))
+    return all(
+        isclose(a, b, rel_tol=rel_tol, abs_tol=abs_tol) for a, b in zip(a_list, b_list)
+    )
 
 
 def test_generalized_iterators():
@@ -51,7 +53,7 @@ def test_sequence():
     cstats = ConstructorStats.get(m.Sequence)
 
     s = m.Sequence(5)
-    assert cstats.values() == ['of size', '5']
+    assert cstats.values() == ["of size", "5"]
 
     assert "Sequence" in repr(s)
     assert len(s) == 5
@@ -62,16 +64,16 @@ def test_sequence():
     assert isclose(s[0], 12.34) and isclose(s[3], 56.78)
 
     rev = reversed(s)
-    assert cstats.values() == ['of size', '5']
+    assert cstats.values() == ["of size", "5"]
 
     rev2 = s[::-1]
-    assert cstats.values() == ['of size', '5']
+    assert cstats.values() == ["of size", "5"]
 
     it = iter(m.Sequence(0))
     for _ in range(3):  # __next__ must continue to raise StopIteration
         with pytest.raises(StopIteration):
             next(it)
-    assert cstats.values() == ['of size', '0']
+    assert cstats.values() == ["of size", "0"]
 
     expected = [0, 56.78, 0, 0, 12.34]
     assert allclose(rev, expected)
@@ -79,7 +81,7 @@ def test_sequence():
     assert rev == rev2
 
     rev[0::2] = m.Sequence([2.0, 2.0, 2.0])
-    assert cstats.values() == ['of size', '3', 'from std::vector']
+    assert cstats.values() == ["of size", "3", "from std::vector"]
 
     assert allclose(rev, [2, 56.78, 2, 0, 2])
 
@@ -103,10 +105,11 @@ def test_sequence():
 
 def test_sequence_length():
     """#2076: Exception raised by len(arg) should be propagated """
+
     class BadLen(RuntimeError):
         pass
 
-    class SequenceLike():
+    class SequenceLike:
         def __getitem__(self, i):
             return None
 
@@ -121,17 +124,17 @@ def test_sequence_length():
 
 
 def test_map_iterator():
-    sm = m.StringMap({'hi': 'bye', 'black': 'white'})
-    assert sm['hi'] == 'bye'
+    sm = m.StringMap({"hi": "bye", "black": "white"})
+    assert sm["hi"] == "bye"
     assert len(sm) == 2
-    assert sm['black'] == 'white'
+    assert sm["black"] == "white"
 
     with pytest.raises(KeyError):
-        assert sm['orange']
-    sm['orange'] = 'banana'
-    assert sm['orange'] == 'banana'
+        assert sm["orange"]
+    sm["orange"] = "banana"
+    assert sm["orange"] == "banana"
 
-    expected = {'hi': 'bye', 'black': 'white', 'orange': 'banana'}
+    expected = {"hi": "bye", "black": "white", "orange": "banana"}
     for k in sm:
         assert sm[k] == expected[k]
     for k, v in sm.items():
@@ -179,7 +182,8 @@ def test_iterator_passthrough():
     """#181: iterator passthrough did not compile"""
     from pybind11_tests.sequences_and_iterators import iterator_passthrough
 
-    assert list(iterator_passthrough(iter([3, 5, 7, 9, 11, 13, 15]))) == [3, 5, 7, 9, 11, 13, 15]
+    values = [3, 5, 7, 9, 11, 13, 15]
+    assert list(iterator_passthrough(iter(values))) == values
 
 
 def test_iterator_rvp():

tests/test_smart_ptr.py

@@ -7,7 +7,9 @@ from pybind11_tests import ConstructorStats  # noqa: E402
 
 def test_smart_ptr(capture):
     # Object1
-    for i, o in enumerate([m.make_object_1(), m.make_object_2(), m.MyObject1(3)], start=1):
+    for i, o in enumerate(
+        [m.make_object_1(), m.make_object_2(), m.MyObject1(3)], start=1
+    ):
         assert o.getRefCount() == 1
         with capture:
             m.print_object_1(o)
@@ -16,8 +18,9 @@ def test_smart_ptr(capture):
             m.print_object_4(o)
         assert capture == "MyObject1[{i}]\n".format(i=i) * 4
 
-    for i, o in enumerate([m.make_myobject1_1(), m.make_myobject1_2(), m.MyObject1(6), 7],
-                          start=4):
+    for i, o in enumerate(
+        [m.make_myobject1_1(), m.make_myobject1_2(), m.MyObject1(6), 7], start=4
+    ):
         print(o)
         with capture:
             if not isinstance(o, int):
@@ -29,11 +32,15 @@ def test_smart_ptr(capture):
             m.print_myobject1_2(o)
             m.print_myobject1_3(o)
             m.print_myobject1_4(o)
-        assert capture == "MyObject1[{i}]\n".format(i=i) * (4 if isinstance(o, int) else 8)
+
+        times = 4 if isinstance(o, int) else 8
+        assert capture == "MyObject1[{i}]\n".format(i=i) * times
 
     cstats = ConstructorStats.get(m.MyObject1)
     assert cstats.alive() == 0
-    expected_values = ['MyObject1[{}]'.format(i) for i in range(1, 7)] + ['MyObject1[7]'] * 4
+    expected_values = ["MyObject1[{}]".format(i) for i in range(1, 7)] + [
+        "MyObject1[7]"
+    ] * 4
     assert cstats.values() == expected_values
     assert cstats.default_constructions == 0
     assert cstats.copy_constructions == 0
@@ -42,7 +49,9 @@ def test_smart_ptr(capture):
     assert cstats.move_assignments == 0
 
     # Object2
-    for i, o in zip([8, 6, 7], [m.MyObject2(8), m.make_myobject2_1(), m.make_myobject2_2()]):
+    for i, o in zip(
+        [8, 6, 7], [m.MyObject2(8), m.make_myobject2_1(), m.make_myobject2_2()]
+    ):
         print(o)
         with capture:
             m.print_myobject2_1(o)
@@ -55,7 +64,7 @@ def test_smart_ptr(capture):
     assert cstats.alive() == 1
     o = None
     assert cstats.alive() == 0
-    assert cstats.values() == ['MyObject2[8]', 'MyObject2[6]', 'MyObject2[7]']
+    assert cstats.values() == ["MyObject2[8]", "MyObject2[6]", "MyObject2[7]"]
     assert cstats.default_constructions == 0
     assert cstats.copy_constructions == 0
     # assert cstats.move_constructions >= 0 # Doesn't invoke any
@@ -63,7 +72,9 @@ def test_smart_ptr(capture):
     assert cstats.move_assignments == 0
 
     # Object3
-    for i, o in zip([9, 8, 9], [m.MyObject3(9), m.make_myobject3_1(), m.make_myobject3_2()]):
+    for i, o in zip(
+        [9, 8, 9], [m.MyObject3(9), m.make_myobject3_1(), m.make_myobject3_2()]
+    ):
         print(o)
         with capture:
             m.print_myobject3_1(o)
@@ -76,7 +87,7 @@ def test_smart_ptr(capture):
     assert cstats.alive() == 1
     o = None
     assert cstats.alive() == 0
-    assert cstats.values() == ['MyObject3[9]', 'MyObject3[8]', 'MyObject3[9]']
+    assert cstats.values() == ["MyObject3[9]", "MyObject3[8]", "MyObject3[9]"]
     assert cstats.default_constructions == 0
     assert cstats.copy_constructions == 0
     # assert cstats.move_constructions >= 0 # Doesn't invoke any
@@ -96,7 +107,7 @@ def test_smart_ptr(capture):
     # ref<>
     cstats = m.cstats_ref()
     assert cstats.alive() == 0
-    assert cstats.values() == ['from pointer'] * 10
+    assert cstats.values() == ["from pointer"] * 10
     assert cstats.default_constructions == 30
     assert cstats.copy_constructions == 12
     # assert cstats.move_constructions >= 0 # Doesn't invoke any
@@ -186,7 +197,9 @@ def test_shared_ptr_from_this_and_references():
     ref = s.ref  # init_holder_helper(holder_ptr=false, owned=false, bad_wp=false)
     assert stats.alive() == 2
     assert s.set_ref(ref)
-    assert s.set_holder(ref)  # std::enable_shared_from_this can create a holder from a reference
+    assert s.set_holder(
+        ref
+    )  # std::enable_shared_from_this can create a holder from a reference
 
     bad_wp = s.bad_wp  # init_holder_helper(holder_ptr=false, owned=false, bad_wp=true)
     assert stats.alive() == 2
@@ -200,12 +213,16 @@ def test_shared_ptr_from_this_and_references():
     assert s.set_ref(copy)
     assert s.set_holder(copy)
 
-    holder_ref = s.holder_ref  # init_holder_helper(holder_ptr=true, owned=false, bad_wp=false)
+    holder_ref = (
+        s.holder_ref
+    )  # init_holder_helper(holder_ptr=true, owned=false, bad_wp=false)
     assert stats.alive() == 3
     assert s.set_ref(holder_ref)
     assert s.set_holder(holder_ref)
 
-    holder_copy = s.holder_copy  # init_holder_helper(holder_ptr=true, owned=true, bad_wp=false)
+    holder_copy = (
+        s.holder_copy
+    )  # init_holder_helper(holder_ptr=true, owned=true, bad_wp=false)
     assert stats.alive() == 3
     assert s.set_ref(holder_copy)
     assert s.set_holder(holder_copy)
@@ -277,8 +294,10 @@ def test_smart_ptr_from_default():
     instance = m.HeldByDefaultHolder()
     with pytest.raises(RuntimeError) as excinfo:
         m.HeldByDefaultHolder.load_shared_ptr(instance)
-    assert "Unable to load a custom holder type from a " \
+    assert (
+        "Unable to load a custom holder type from a "
         "default-holder instance" in str(excinfo.value)
+    )
 
 
 def test_shared_ptr_gc():

tests/test_stl.py

@@ -88,7 +88,7 @@ def test_recursive_casting():
     assert m.cast_rv_nested() == [[[{"b": "rvalue", "c": "rvalue"}], [{"a": "rvalue"}]]]
     assert m.cast_lv_nested() == {
         "a": [[["lvalue", "lvalue"]], [["lvalue", "lvalue"]]],
-        "b": [[["lvalue", "lvalue"], ["lvalue", "lvalue"]]]
+        "b": [[["lvalue", "lvalue"], ["lvalue", "lvalue"]]],
     }
 
     # Issue #853 test case:
@@ -106,15 +106,15 @@ def test_move_out_container():
     assert [x.value for x in moved_out_list] == [0, 1, 2]
 
 
-@pytest.mark.skipif(not hasattr(m, "has_optional"), reason='no <optional>')
+@pytest.mark.skipif(not hasattr(m, "has_optional"), reason="no <optional>")
 def test_optional():
     assert m.double_or_zero(None) == 0
     assert m.double_or_zero(42) == 84
-    pytest.raises(TypeError, m.double_or_zero, 'foo')
+    pytest.raises(TypeError, m.double_or_zero, "foo")
 
     assert m.half_or_none(0) is None
     assert m.half_or_none(42) == 21
-    pytest.raises(TypeError, m.half_or_none, 'foo')
+    pytest.raises(TypeError, m.half_or_none, "foo")
 
     assert m.test_nullopt() == 42
     assert m.test_nullopt(None) == 42
@@ -134,15 +134,17 @@ def test_optional():
     assert holder.member_initialized()
 
 
-@pytest.mark.skipif(not hasattr(m, "has_exp_optional"), reason='no <experimental/optional>')
+@pytest.mark.skipif(
+    not hasattr(m, "has_exp_optional"), reason="no <experimental/optional>"
+)
 def test_exp_optional():
     assert m.double_or_zero_exp(None) == 0
     assert m.double_or_zero_exp(42) == 84
-    pytest.raises(TypeError, m.double_or_zero_exp, 'foo')
+    pytest.raises(TypeError, m.double_or_zero_exp, "foo")
 
     assert m.half_or_none_exp(0) is None
     assert m.half_or_none_exp(42) == 21
-    pytest.raises(TypeError, m.half_or_none_exp, 'foo')
+    pytest.raises(TypeError, m.half_or_none_exp, "foo")
 
     assert m.test_nullopt_exp() == 42
     assert m.test_nullopt_exp(None) == 42
@@ -160,7 +162,7 @@ def test_exp_optional():
     assert holder.member_initialized()
 
 
-@pytest.mark.skipif(not hasattr(m, "load_variant"), reason='no <variant>')
+@pytest.mark.skipif(not hasattr(m, "load_variant"), reason="no <variant>")
 def test_variant(doc):
     assert m.load_variant(1) == "int"
     assert m.load_variant("1") == "std::string"
@@ -172,34 +174,44 @@ def test_variant(doc):
 
     assert m.cast_variant() == (5, "Hello")
 
-    assert doc(m.load_variant) == "load_variant(arg0: Union[int, str, float, None]) -> str"
+    assert (
+        doc(m.load_variant) == "load_variant(arg0: Union[int, str, float, None]) -> str"
+    )
 
 
 def test_vec_of_reference_wrapper():
     """#171: Can't return reference wrappers (or STL structures containing them)"""
-    assert str(m.return_vec_of_reference_wrapper(UserType(4))) == \
-        "[UserType(1), UserType(2), UserType(3), UserType(4)]"
+    assert (
+        str(m.return_vec_of_reference_wrapper(UserType(4)))
+        == "[UserType(1), UserType(2), UserType(3), UserType(4)]"
+    )
 
 
 def test_stl_pass_by_pointer(msg):
     """Passing nullptr or None to an STL container pointer is not expected to work"""
     with pytest.raises(TypeError) as excinfo:
         m.stl_pass_by_pointer()  # default value is `nullptr`
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         stl_pass_by_pointer(): incompatible function arguments. The following argument types are supported:
             1. (v: List[int] = None) -> List[int]
 
         Invoked with:
     """  # noqa: E501 line too long
+    )
 
     with pytest.raises(TypeError) as excinfo:
         m.stl_pass_by_pointer(None)
-    assert msg(excinfo.value) == """
+    assert (
+        msg(excinfo.value)
+        == """
         stl_pass_by_pointer(): incompatible function arguments. The following argument types are supported:
             1. (v: List[int] = None) -> List[int]
 
         Invoked with: None
     """  # noqa: E501 line too long
+    )
 
     assert m.stl_pass_by_pointer([1, 2, 3]) == [1, 2, 3]
 
@@ -209,10 +221,12 @@ def test_missing_header_message():
     <pybind11/stl.h> should result in a helpful suggestion in the error message"""
     import pybind11_cross_module_tests as cm
 
-    expected_message = ("Did you forget to `#include <pybind11/stl.h>`? Or <pybind11/complex.h>,\n"
+    expected_message = (
+        "Did you forget to `#include <pybind11/stl.h>`? Or <pybind11/complex.h>,\n"
         "<pybind11/functional.h>, <pybind11/chrono.h>, etc. Some automatic\n"
         "conversions are optional and require extra headers to be included\n"
-                        "when compiling your pybind11 module.")
+        "when compiling your pybind11 module."
+    )
 
     with pytest.raises(TypeError) as excinfo:
         cm.missing_header_arg([1.0, 2.0, 3.0])
@@ -226,9 +240,9 @@ def test_missing_header_message():
 def test_function_with_string_and_vector_string_arg():
     """Check if a string is NOT implicitly converted to a list, which was the
     behavior before fix of issue #1258"""
-    assert m.func_with_string_or_vector_string_arg_overload(('A', 'B', )) == 2
-    assert m.func_with_string_or_vector_string_arg_overload(['A', 'B']) == 2
-    assert m.func_with_string_or_vector_string_arg_overload('A') == 3
+    assert m.func_with_string_or_vector_string_arg_overload(("A", "B")) == 2
+    assert m.func_with_string_or_vector_string_arg_overload(["A", "B"]) == 2
+    assert m.func_with_string_or_vector_string_arg_overload("A") == 3
 
 
 def test_stl_ownership():
@@ -247,6 +261,6 @@ def test_array_cast_sequence():
 def test_issue_1561():
     """ check fix for issue #1561 """
     bar = m.Issue1561Outer()
-    bar.list = [m.Issue1561Inner('bar')]
+    bar.list = [m.Issue1561Inner("bar")]
     bar.list
-    assert bar.list[0].data == 'bar'
+    assert bar.list[0].data == "bar"

tests/test_stl_binders.py

@@ -45,7 +45,7 @@ def test_vector_int():
 
     # test error handling, and that the vector is unchanged
     with pytest.raises(RuntimeError):
-        v_int2.extend([8, 'a'])
+        v_int2.extend([8, "a"])
 
     assert v_int2 == m.VectorInt([0, 99, 2, 3, 4, 5, 6, 7])
 
@@ -79,8 +79,8 @@ def test_vector_buffer():
         assert mv[2] == 5
         mv[2] = 6
     else:
-        assert mv[2] == '\x05'
-        mv[2] = '\x06'
+        assert mv[2] == "\x05"
+        mv[2] = "\x06"
     assert v[2] == 6
 
     if not env.PY2:
@@ -114,11 +114,17 @@ def test_vector_buffer_numpy():
     v = m.get_vectorstruct()
     assert v[0].x == 5
     ma = np.asarray(v)
-    ma[1]['x'] = 99
+    ma[1]["x"] = 99
     assert v[1].x == 99
 
-    v = m.VectorStruct(np.zeros(3, dtype=np.dtype([('w', 'bool'), ('x', 'I'),
-                                                   ('y', 'float64'), ('z', 'bool')], align=True)))
+    v = m.VectorStruct(
+        np.zeros(
+            3,
+            dtype=np.dtype(
+                [("w", "bool"), ("x", "I"), ("y", "float64"), ("z", "bool")], align=True
+            ),
+        )
+    )
     assert len(v) == 3
 
     b = np.array([1, 2, 3, 4], dtype=np.uint8)
@@ -151,31 +157,31 @@ def test_vector_custom():
 
 def test_map_string_double():
     mm = m.MapStringDouble()
-    mm['a'] = 1
-    mm['b'] = 2.5
+    mm["a"] = 1
+    mm["b"] = 2.5
 
-    assert list(mm) == ['a', 'b']
-    assert list(mm.items()) == [('a', 1), ('b', 2.5)]
+    assert list(mm) == ["a", "b"]
+    assert list(mm.items()) == [("a", 1), ("b", 2.5)]
     assert str(mm) == "MapStringDouble{a: 1, b: 2.5}"
 
     um = m.UnorderedMapStringDouble()
-    um['ua'] = 1.1
-    um['ub'] = 2.6
+    um["ua"] = 1.1
+    um["ub"] = 2.6
 
-    assert sorted(list(um)) == ['ua', 'ub']
-    assert sorted(list(um.items())) == [('ua', 1.1), ('ub', 2.6)]
+    assert sorted(list(um)) == ["ua", "ub"]
+    assert sorted(list(um.items())) == [("ua", 1.1), ("ub", 2.6)]
     assert "UnorderedMapStringDouble" in str(um)
 
 
 def test_map_string_double_const():
     mc = m.MapStringDoubleConst()
-    mc['a'] = 10
-    mc['b'] = 20.5
+    mc["a"] = 10
+    mc["b"] = 20.5
     assert str(mc) == "MapStringDoubleConst{a: 10, b: 20.5}"
 
     umc = m.UnorderedMapStringDoubleConst()
-    umc['a'] = 11
-    umc['b'] = 21.5
+    umc["a"] = 11
+    umc["b"] = 21.5
 
     str(umc)
 
@@ -196,7 +202,7 @@ def test_noncopyable_containers():
 
     i = 1
     for j in dnc:
-        assert(j.value == i)
+        assert j.value == i
         i += 1
 
     # std::map
@@ -265,21 +271,21 @@ def test_noncopyable_containers():
 
 def test_map_delitem():
     mm = m.MapStringDouble()
-    mm['a'] = 1
-    mm['b'] = 2.5
+    mm["a"] = 1
+    mm["b"] = 2.5
 
-    assert list(mm) == ['a', 'b']
-    assert list(mm.items()) == [('a', 1), ('b', 2.5)]
-    del mm['a']
-    assert list(mm) == ['b']
-    assert list(mm.items()) == [('b', 2.5)]
+    assert list(mm) == ["a", "b"]
+    assert list(mm.items()) == [("a", 1), ("b", 2.5)]
+    del mm["a"]
+    assert list(mm) == ["b"]
+    assert list(mm.items()) == [("b", 2.5)]
 
     um = m.UnorderedMapStringDouble()
-    um['ua'] = 1.1
-    um['ub'] = 2.6
-
-    assert sorted(list(um)) == ['ua', 'ub']
-    assert sorted(list(um.items())) == [('ua', 1.1), ('ub', 2.6)]
-    del um['ua']
-    assert sorted(list(um)) == ['ub']
-    assert sorted(list(um.items())) == [('ub', 2.6)]
+    um["ua"] = 1.1
+    um["ub"] = 2.6
+
+    assert sorted(list(um)) == ["ua", "ub"]
+    assert sorted(list(um.items())) == [("ua", 1.1), ("ub", 2.6)]
+    del um["ua"]
+    assert sorted(list(um)) == ["ub"]
+    assert sorted(list(um.items())) == [("ub", 2.6)]

tests/test_tagbased_polymorphic.py

@@ -5,16 +5,24 @@ from pybind11_tests import tagbased_polymorphic as m
 def test_downcast():
     zoo = m.create_zoo()
     assert [type(animal) for animal in zoo] == [
-        m.Labrador, m.Dog, m.Chihuahua, m.Cat, m.Panther
+        m.Labrador,
+        m.Dog,
+        m.Chihuahua,
+        m.Cat,
+        m.Panther,
     ]
     assert [animal.name for animal in zoo] == [
-        "Fido", "Ginger", "Hertzl", "Tiger", "Leo"
+        "Fido",
+        "Ginger",
+        "Hertzl",
+        "Tiger",
+        "Leo",
     ]
     zoo[1].sound = "woooooo"
     assert [dog.bark() for dog in zoo[:3]] == [
         "Labrador Fido goes WOOF!",
         "Dog Ginger goes woooooo",
-        "Chihuahua Hertzl goes iyiyiyiyiyi and runs in circles"
+        "Chihuahua Hertzl goes iyiyiyiyiyi and runs in circles",
     ]
     assert [cat.purr() for cat in zoo[3:]] == ["mrowr", "mrrrRRRRRR"]
     zoo[0].excitement -= 1000

tests/test_virtual_functions.py

@@ -14,18 +14,18 @@ def test_override(capture, msg):
             self.data = "Hello world"
 
         def run(self, value):
-            print('ExtendedExampleVirt::run(%i), calling parent..' % value)
+            print("ExtendedExampleVirt::run(%i), calling parent.." % value)
             return super(ExtendedExampleVirt, self).run(value + 1)
 
         def run_bool(self):
-            print('ExtendedExampleVirt::run_bool()')
+            print("ExtendedExampleVirt::run_bool()")
             return False
 
         def get_string1(self):
             return "override1"
 
         def pure_virtual(self):
-            print('ExtendedExampleVirt::pure_virtual(): %s' % self.data)
+            print("ExtendedExampleVirt::pure_virtual(): %s" % self.data)
 
     class ExtendedExampleVirt2(ExtendedExampleVirt):
         def __init__(self, state):
@@ -37,21 +37,30 @@ def test_override(capture, msg):
     ex12 = m.ExampleVirt(10)
     with capture:
         assert m.runExampleVirt(ex12, 20) == 30
-    assert capture == """
+    assert (
+        capture
+        == """
         Original implementation of ExampleVirt::run(state=10, value=20, str1=default1, str2=default2)
     """  # noqa: E501 line too long
+    )
 
     with pytest.raises(RuntimeError) as excinfo:
         m.runExampleVirtVirtual(ex12)
-    assert msg(excinfo.value) == 'Tried to call pure virtual function "ExampleVirt::pure_virtual"'
+    assert (
+        msg(excinfo.value)
+        == 'Tried to call pure virtual function "ExampleVirt::pure_virtual"'
+    )
 
     ex12p = ExtendedExampleVirt(10)
     with capture:
         assert m.runExampleVirt(ex12p, 20) == 32
-    assert capture == """
+    assert (
+        capture
+        == """
         ExtendedExampleVirt::run(20), calling parent..
         Original implementation of ExampleVirt::run(state=11, value=21, str1=override1, str2=default2)
     """  # noqa: E501 line too long
+    )
     with capture:
         assert m.runExampleVirtBool(ex12p) is False
     assert capture == "ExtendedExampleVirt::run_bool()"
@@ -62,16 +71,19 @@ def test_override(capture, msg):
     ex12p2 = ExtendedExampleVirt2(15)
     with capture:
         assert m.runExampleVirt(ex12p2, 50) == 68
-    assert capture == """
+    assert (
+        capture
+        == """
         ExtendedExampleVirt::run(50), calling parent..
         Original implementation of ExampleVirt::run(state=17, value=51, str1=override1, str2=override2)
     """  # noqa: E501 line too long
+    )
 
     cstats = ConstructorStats.get(m.ExampleVirt)
     assert cstats.alive() == 3
     del ex12, ex12p, ex12p2
     assert cstats.alive() == 0
-    assert cstats.values() == ['10', '11', '17']
+    assert cstats.values() == ["10", "11", "17"]
     assert cstats.copy_constructions == 0
     assert cstats.move_constructions >= 0
 
@@ -82,6 +94,7 @@ def test_alias_delay_initialization1(capture):
     If we just create and use an A instance directly, the trampoline initialization is
     bypassed and we only initialize an A() instead (for performance reasons).
     """
+
     class B(m.A):
         def __init__(self):
             super(B, self).__init__()
@@ -103,12 +116,15 @@ def test_alias_delay_initialization1(capture):
         m.call_f(b)
         del b
         pytest.gc_collect()
-    assert capture == """
+    assert (
+        capture
+        == """
         PyA.PyA()
         PyA.f()
         In python f()
         PyA.~PyA()
     """
+    )
 
 
 def test_alias_delay_initialization2(capture):
@@ -118,6 +134,7 @@ def test_alias_delay_initialization2(capture):
     performance penalty, it also allows us to do more things with the trampoline
     class such as defining local variables and performing construction/destruction.
     """
+
     class B2(m.A2):
         def __init__(self):
             super(B2, self).__init__()
@@ -135,7 +152,9 @@ def test_alias_delay_initialization2(capture):
         m.call_f(a3)
         del a3
         pytest.gc_collect()
-    assert capture == """
+    assert (
+        capture
+        == """
         PyA2.PyA2()
         PyA2.f()
         A2.f()
@@ -145,6 +164,7 @@ def test_alias_delay_initialization2(capture):
         A2.f()
         PyA2.~PyA2()
     """
+    )
 
     # Python subclass version
     with capture:
@@ -152,20 +172,22 @@ def test_alias_delay_initialization2(capture):
         m.call_f(b2)
         del b2
         pytest.gc_collect()
-    assert capture == """
+    assert (
+        capture
+        == """
         PyA2.PyA2()
         PyA2.f()
         In python B2.f()
         PyA2.~PyA2()
     """
+    )
 
 
 # PyPy: Reference count > 1 causes call with noncopyable instance
 # to fail in ncv1.print_nc()
 @pytest.mark.xfail("env.PYPY")
 @pytest.mark.skipif(
-    not hasattr(m, "NCVirt"),
-    reason="NCVirt does not work on Intel/PGI/NVCC compilers"
+    not hasattr(m, "NCVirt"), reason="NCVirt does not work on Intel/PGI/NVCC compilers"
 )
 def test_move_support():
     class NCVirtExt(m.NCVirt):
@@ -205,8 +227,8 @@ def test_move_support():
     del ncv1, ncv2
     assert nc_stats.alive() == 0
     assert mv_stats.alive() == 0
-    assert nc_stats.values() == ['4', '9', '9', '9']
-    assert mv_stats.values() == ['4', '5', '7', '7']
+    assert nc_stats.values() == ["4", "9", "9", "9"]
+    assert mv_stats.values() == ["4", "5", "7", "7"]
     assert nc_stats.copy_constructions == 0
     assert mv_stats.copy_constructions == 1
     assert nc_stats.move_constructions >= 0
@@ -215,6 +237,7 @@ def test_move_support():
 
 def test_dispatch_issue(msg):
     """#159: virtual function dispatch has problems with similar-named functions"""
+
     class PyClass1(m.DispatchIssue):
         def dispatch(self):
             return "Yay.."
@@ -223,7 +246,10 @@ def test_dispatch_issue(msg):
         def dispatch(self):
             with pytest.raises(RuntimeError) as excinfo:
                 super(PyClass2, self).dispatch()
-            assert msg(excinfo.value) == 'Tried to call pure virtual function "Base::dispatch"'
+            assert (
+                msg(excinfo.value)
+                == 'Tried to call pure virtual function "Base::dispatch"'
+            )
 
             p = PyClass1()
             return m.dispatch_issue_go(p)
@@ -339,7 +365,7 @@ def test_inherited_virtuals():
 
     class DT(m.D_Tpl):
         def say_something(self, times):
-            return "DT says:" + (' quack' * times)
+            return "DT says:" + (" quack" * times)
 
         def unlucky_number(self):
             return 1234
@@ -355,7 +381,7 @@ def test_inherited_virtuals():
 
     class DT2(DT):
         def say_something(self, times):
-            return "DT2: " + ('QUACK' * times)
+            return "DT2: " + ("QUACK" * times)
 
         def unlucky_number(self):
             return -3