[CI] Run unit test with non-editable installation (#845)

We have been running unit test with editable installation. (i.e. `python setup.py develop`), with which we missed issues like #842. 

This CC makes installation in CI non-editable, and change test directory structure so that the source code will not shadow the installed version of `torchaudio`. With simple `pytest test`, `pytest` modifies `sys.path` and prepend checked out repository, which shadows the installed version.

To remedy this, the whole test suites has been moved from `./test` to `./test/torchaudio_unittest`. This adds nice module structure to our test code and we can do absolute import in each test module, which makes it possible again to run test with `python -m unittest torchaudio_unittest/XXX.py`

This change does not affect the regular development process (`python setup.py develop` && `pytest test`)

test/test_models.py → test/torchaudio_unittest/models_test.py

 import torch
 from torchaudio.models import Wav2Letter, MelResNet, UpsampleNetwork, WaveRNN
 
-from . import common_utils
+from torchaudio_unittest import common_utils
 
 
 class TestWav2Letter(common_utils.TorchaudioTestCase):

test/test_sox_compatibility.py → test/torchaudio_unittest/sox_compatibility_test.py

@@ -5,7 +5,7 @@ import torchaudio.functional as F
 import torchaudio.transforms as T
 from parameterized import parameterized
 
-from .common_utils import (
+from torchaudio_unittest.common_utils import (
     skipIfNoSoxBackend,
     skipIfNoExec,
     TempDirMixin,

test/sox_effect/common.py → test/torchaudio_unittest/sox_effect/common.py

@@ -2,7 +2,7 @@ import json
 
 from parameterized import param
 
-from ..common_utils import get_asset_path
+from torchaudio_unittest.common_utils import get_asset_path
 
 
 def name_func(func, _, params):

test/sox_effect/test_dataset.py → test/torchaudio_unittest/sox_effect/dataset_test.py

@@ -4,7 +4,7 @@ import numpy as np
 import torch
 import torchaudio
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     PytorchTestCase,
     skipIfNoExtension,

test/sox_effect/smoke_test.py → test/torchaudio_unittest/sox_effect/smoke_test.py

 from torchaudio import sox_effects
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     TorchaudioTestCase,
     skipIfNoExtension,

test/sox_effect/test_sox_effect.py → test/torchaudio_unittest/sox_effect/sox_effect_test.py

@@ -3,7 +3,7 @@ import itertools
 from torchaudio import sox_effects
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     PytorchTestCase,
     skipIfNoExtension,

test/sox_effect/test_torchscript.py → test/torchaudio_unittest/sox_effect/torchscript_test.py

@@ -4,7 +4,7 @@ import torch
 from torchaudio import sox_effects
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     PytorchTestCase,
     skipIfNoExtension,

test/sox_io_backend/test_info.py → test/torchaudio_unittest/sox_io_backend/info_test.py

@@ -3,7 +3,7 @@ from parameterized import parameterized
 
 from torchaudio.backend import sox_io_backend
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     PytorchTestCase,
     skipIfNoExec,

test/sox_io_backend/test_load.py → test/torchaudio_unittest/sox_io_backend/load_test.py

@@ -3,7 +3,7 @@ import itertools
 from torchaudio.backend import sox_io_backend
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     PytorchTestCase,
     skipIfNoExec,

test/sox_io_backend/test_roundtrip.py → test/torchaudio_unittest/sox_io_backend/roundtrip_test.py

@@ -3,7 +3,7 @@ import itertools
 from torchaudio.backend import sox_io_backend
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     PytorchTestCase,
     skipIfNoExec,

test/sox_io_backend/test_save.py → test/torchaudio_unittest/sox_io_backend/save_test.py

@@ -3,7 +3,7 @@ import itertools
 from torchaudio.backend import sox_io_backend
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     PytorchTestCase,
     skipIfNoExec,

test/sox_io_backend/smoke_test.py → test/torchaudio_unittest/sox_io_backend/smoke_test.py

@@ -6,7 +6,7 @@ from torchaudio.backend import sox_io_backend
 from torchaudio._internal.module_utils import is_module_available
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     TorchaudioTestCase,
     skipIfNoExtension,

test/sox_io_backend/test_torchscript.py → test/torchaudio_unittest/sox_io_backend/torchscript_test.py

@@ -5,7 +5,7 @@ import torch
 import torchaudio
 from parameterized import parameterized
 
-from ..common_utils import (
+from torchaudio_unittest.common_utils import (
     TempDirMixin,
     TorchaudioTestCase,
     skipIfNoExec,

test/torchscript_consistency_cpu_test.py → test/torchaudio_unittest/torchscript_consistency_cpu_test.py

 import torch
 
-from . import common_utils
+from torchaudio_unittest import common_utils
 from .torchscript_consistency_impl import Functional, Transforms
 
 

test/torchscript_consistency_cuda_test.py → test/torchaudio_unittest/torchscript_consistency_cuda_test.py

 import torch
 
-from . import common_utils
+from torchaudio_unittest import common_utils
 from .torchscript_consistency_impl import Functional, Transforms
 
 

test/torchscript_consistency_impl.py → test/torchaudio_unittest/torchscript_consistency_impl.py

@@ -5,7 +5,7 @@ import torch
 import torchaudio.functional as F
 import torchaudio.transforms as T
 
-from . import common_utils
+from torchaudio_unittest import common_utils
 
 
 class Functional(common_utils.TestBaseMixin):