Add test util for checking stand-alone python scripts (#1007)

* Add test util for checking stand-alone scripts
Signed-off-by: lizz <lizz@sensetime.com>

* Restrict to python scripts
Signed-off-by: lizz <lizz@sensetime.com>

* fix
Signed-off-by: lizz <lizz@sensetime.com>

* tiny
Signed-off-by: lizz <lizz@sensetime.com>

* Allow no capture
Signed-off-by: lizz <lizz@sensetime.com>

* Simplify interface
Signed-off-by: lizz <lizz@sensetime.com>

* Technical notes
Signed-off-by: lizz <lizz@sensetime.com>

* tiny
Signed-off-by: lizz <lizz@sensetime.com>

* Update hello.py

* Update test_testing.py

* Update test_testing.py

mmcv/utils/__init__.py

@@ -11,7 +11,8 @@ from .progressbar import (ProgressBar, track_iter_progress,
                           track_parallel_progress, track_progress)
 from .testing import (assert_attrs_equal, assert_dict_contains_subset,
                       assert_dict_has_keys, assert_is_norm_layer,
-                      assert_keys_equal, assert_params_all_zeros)
+                      assert_keys_equal, assert_params_all_zeros,
+                      check_python_script)
 from .timer import Timer, TimerError, check_time
 from .version_utils import digit_version, get_git_hash
 
@@ -28,7 +29,7 @@ except ImportError:
         'Timer', 'TimerError', 'check_time', 'deprecated_api_warning',
         'digit_version', 'get_git_hash', 'import_modules_from_strings',
         'assert_dict_contains_subset', 'assert_attrs_equal',
-        'assert_dict_has_keys', 'assert_keys_equal'
+        'assert_dict_has_keys', 'assert_keys_equal', 'check_python_script'
     ]
 else:
     from .env import collect_env
@@ -57,5 +58,5 @@ else:
         'get_git_hash', 'import_modules_from_strings', 'jit', 'skip_no_elena',
         'assert_dict_contains_subset', 'assert_attrs_equal',
         'assert_dict_has_keys', 'assert_keys_equal', 'assert_is_norm_layer',
-        'assert_params_all_zeros'
+        'assert_params_all_zeros', 'check_python_script'
     ]

mmcv/utils/testing.py

 # Copyright (c) Open-MMLab.
+import sys
 from collections.abc import Iterable
+from runpy import run_path
+from shlex import split
 from typing import Any, Dict, List
+from unittest.mock import patch
+
+
+def check_python_script(cmd):
+    """Run the python cmd script with `__main__`. The difference between
+    `os.system` is that, this function exectues code in the current process, so
+    that it can be tracked by coverage tools. Currently it supports two forms:
+
+    - ./tests/data/scripts/hello.py zz
+    - python tests/data/scripts/hello.py zz
+    """
+    args = split(cmd)
+    if args[0] == 'python':
+        args = args[1:]
+    with patch.object(sys, 'argv', args):
+        run_path(args[0], run_name='__main__')
 
 
 def _any(judge_result):

tests/data/scripts/hello.py

+#!/usr/bin/env python
+
+import argparse
+import warnings
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(description='Say hello.')
+    parser.add_argument('name', help='To whom.')
+
+    args = parser.parse_args()
+
+    return args
+
+
+def main():
+    args = parse_args()
+    print(f'hello {args.name}!')
+    if args.name == 'agent':
+        warnings.warn('I have a secret!')
+
+
+if __name__ == '__main__':
+    main()

tests/test_utils/test_testing.py

@@ -180,3 +180,15 @@ def test_assert_params_all_zeros():
 
     nn.init.normal_(demo_module.weight, mean=0, std=0.01)
     assert not mmcv.assert_params_all_zeros(demo_module)
+
+
+def test_check_python_script(capsys):
+    mmcv.utils.check_python_script('./tests/data/scripts/hello.py zz')
+    captured = capsys.readouterr().out
+    assert captured == 'hello zz!\n'
+    mmcv.utils.check_python_script('./tests/data/scripts/hello.py agent')
+    captured = capsys.readouterr().out
+    assert captured == 'hello agent!\n'
+    # Make sure that wrong cmd raises an error
+    with pytest.raises(SystemExit):
+        mmcv.utils.check_python_script('./tests/data/scripts/hello.py li zz')