Minor test refactorings (#1011)

* Make tests work on fbcode

* Lint

* Fix rebase error

* Properly use get_file_path_2

* Fix wrong use of get_file_path_2 again

* Missing import

test/common_utils.py

+import os
+import shutil
+import tempfile
+import contextlib
+
+
+@contextlib.contextmanager
+def get_tmp_dir(src=None, **kwargs):
+    tmp_dir = tempfile.mkdtemp(**kwargs)
+    if src is not None:
+        os.rmdir(tmp_dir)
+        shutil.copytree(src, tmp_dir)
+    try:
+        yield tmp_dir
+    finally:
+        shutil.rmtree(tmp_dir)

test/test_datasets.py

 import os
 import sys
-import shutil
 import contextlib
-import tempfile
 import unittest
 import mock
 import numpy as np
 import PIL
 import torch
 import torchvision
+from torch._utils_internal import get_file_path_2
 
 PYTHON2 = sys.version_info[0] == 2
 if PYTHON2:
@@ -16,20 +15,10 @@ if PYTHON2:
 else:
     import pickle
 
-FAKEDATA_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)),
-                            'assets', 'fakedata')
+from common_utils import get_tmp_dir
 
-
-@contextlib.contextmanager
-def tmp_dir(src=None, **kwargs):
-    tmp_dir = tempfile.mkdtemp(**kwargs)
-    if src is not None:
-        os.rmdir(tmp_dir)
-        shutil.copytree(src, tmp_dir)
-    try:
-        yield tmp_dir
-    finally:
-        shutil.rmtree(tmp_dir)
+FAKEDATA_DIR = get_file_path_2(
+    os.path.dirname(os.path.abspath(__file__)), 'assets', 'fakedata')
 
 
 @contextlib.contextmanager
@@ -54,17 +43,14 @@ def get_mnist_data(num_images, cls_name, **kwargs):
             f.write(_encode(num_images))
             f.write(labels.numpy().tobytes())
 
-    tmp_dir = tempfile.mkdtemp(**kwargs)
+    with get_tmp_dir() as tmp_dir:
         raw_dir = os.path.join(tmp_dir, cls_name, "raw")
         os.makedirs(raw_dir)
         _make_image_file(os.path.join(raw_dir, "train-images-idx3-ubyte"), num_images)
         _make_label_file(os.path.join(raw_dir, "train-labels-idx1-ubyte"), num_images)
         _make_image_file(os.path.join(raw_dir, "t10k-images-idx3-ubyte"), num_images)
         _make_label_file(os.path.join(raw_dir, "t10k-labels-idx1-ubyte"), num_images)
-    try:
         yield tmp_dir
-    finally:
-        shutil.rmtree(tmp_dir)
 
 
 @contextlib.contextmanager
@@ -109,7 +95,7 @@ def cifar_root(version):
         _make_pickled_file(obj, file)
 
     params = _get_version_params(version)
-    with tmp_dir() as root:
+    with get_tmp_dir() as root:
         base_folder = os.path.join(root, params['base_folder'])
         os.mkdir(base_folder)
 
@@ -124,7 +110,7 @@ def cifar_root(version):
 
 class Tester(unittest.TestCase):
     def test_imagefolder(self):
-        with tmp_dir(src=os.path.join(FAKEDATA_DIR, 'imagefolder')) as root:
+        with get_tmp_dir(src=os.path.join(FAKEDATA_DIR, 'imagefolder')) as root:
             classes = sorted(['a', 'b'])
             class_a_image_files = [os.path.join(root, 'a', file)
                                    for file in ('a1.png', 'a2.png', 'a3.png')]
@@ -200,7 +186,7 @@ class Tester(unittest.TestCase):
 
     @mock.patch('torchvision.datasets.utils.download_url')
     def test_imagenet(self, mock_download):
-        with tmp_dir(src=os.path.join(FAKEDATA_DIR, 'imagenet')) as root:
+        with get_tmp_dir(src=os.path.join(FAKEDATA_DIR, 'imagenet')) as root:
             dataset = torchvision.datasets.ImageNet(root, split='train', download=True)
             self.assertEqual(len(dataset), 3)
             img, target = dataset[0]

test/test_datasets_utils.py

 import os
-import shutil
+import sys
 import tempfile
 import torchvision.datasets.utils as utils
 import unittest
 import zipfile
 import tarfile
 import gzip
+import warnings
+from torch._utils_internal import get_file_path_2
 
-TEST_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)),
-                         'assets', 'grace_hopper_517x606.jpg')
+from common_utils import get_tmp_dir
+
+if sys.version_info < (3,):
+    from urllib2 import URLError
+else:
+    from urllib.error import URLError
+
+
+TEST_FILE = get_file_path_2(
+    os.path.dirname(os.path.abspath(__file__)), 'assets', 'grace_hopper_517x606.jpg')
 
 
 class Tester(unittest.TestCase):
@@ -17,48 +27,55 @@ class Tester(unittest.TestCase):
         fpath = TEST_FILE
         correct_md5 = '9c0bb82894bb3af7f7675ef2b3b6dcdc'
         false_md5 = ''
-        assert utils.check_md5(fpath, correct_md5)
-        assert not utils.check_md5(fpath, false_md5)
+        self.assertTrue(utils.check_md5(fpath, correct_md5))
+        self.assertFalse(utils.check_md5(fpath, false_md5))
 
     def test_check_integrity(self):
         existing_fpath = TEST_FILE
         nonexisting_fpath = ''
         correct_md5 = '9c0bb82894bb3af7f7675ef2b3b6dcdc'
         false_md5 = ''
-        assert utils.check_integrity(existing_fpath, correct_md5)
-        assert not utils.check_integrity(existing_fpath, false_md5)
-        assert utils.check_integrity(existing_fpath)
-        assert not utils.check_integrity(nonexisting_fpath)
+        self.assertTrue(utils.check_integrity(existing_fpath, correct_md5))
+        self.assertFalse(utils.check_integrity(existing_fpath, false_md5))
+        self.assertTrue(utils.check_integrity(existing_fpath))
+        self.assertFalse(utils.check_integrity(nonexisting_fpath))
 
     def test_download_url(self):
-        temp_dir = tempfile.mkdtemp()
+        with get_tmp_dir() as temp_dir:
             url = "http://github.com/pytorch/vision/archive/master.zip"
+            try:
                 utils.download_url(url, temp_dir)
-        assert not len(os.listdir(temp_dir)) == 0, 'The downloaded root directory is empty after download.'
-        shutil.rmtree(temp_dir)
+                self.assertFalse(len(os.listdir(temp_dir)) == 0)
+            except URLError:
+                msg = "could not download test file '{}'".format(url)
+                warnings.warn(msg, RuntimeWarning)
+                raise unittest.SkipTest(msg)
 
     def test_download_url_retry_http(self):
-        temp_dir = tempfile.mkdtemp()
+        with get_tmp_dir() as temp_dir:
             url = "https://github.com/pytorch/vision/archive/master.zip"
+            try:
                 utils.download_url(url, temp_dir)
-        assert not len(os.listdir(temp_dir)) == 0, 'The downloaded root directory is empty after download.'
-        shutil.rmtree(temp_dir)
+                self.assertFalse(len(os.listdir(temp_dir)) == 0)
+            except URLError:
+                msg = "could not download test file '{}'".format(url)
+                warnings.warn(msg, RuntimeWarning)
+                raise unittest.SkipTest(msg)
 
     def test_extract_zip(self):
-        temp_dir = tempfile.mkdtemp()
+        with get_tmp_dir() as temp_dir:
             with tempfile.NamedTemporaryFile(suffix='.zip') as f:
                 with zipfile.ZipFile(f, 'w') as zf:
                     zf.writestr('file.tst', 'this is the content')
                 utils.extract_archive(f.name, temp_dir)
-            assert os.path.exists(os.path.join(temp_dir, 'file.tst'))
+                self.assertTrue(os.path.exists(os.path.join(temp_dir, 'file.tst')))
                 with open(os.path.join(temp_dir, 'file.tst'), 'r') as nf:
                     data = nf.read()
-            assert data == 'this is the content'
-        shutil.rmtree(temp_dir)
+                self.assertEqual(data, 'this is the content')
 
     def test_extract_tar(self):
         for ext, mode in zip(['.tar', '.tar.gz'], ['w', 'w:gz']):
-            temp_dir = tempfile.mkdtemp()
+            with get_tmp_dir() as temp_dir:
                 with tempfile.NamedTemporaryFile() as bf:
                     bf.write("this is the content".encode())
                     bf.seek(0)
@@ -66,24 +83,22 @@ class Tester(unittest.TestCase):
                         with tarfile.open(f.name, mode=mode) as zf:
                             zf.add(bf.name, arcname='file.tst')
                         utils.extract_archive(f.name, temp_dir)
-                    assert os.path.exists(os.path.join(temp_dir, 'file.tst'))
+                        self.assertTrue(os.path.exists(os.path.join(temp_dir, 'file.tst')))
                         with open(os.path.join(temp_dir, 'file.tst'), 'r') as nf:
                             data = nf.read()
-                    assert data == 'this is the content', data
-            shutil.rmtree(temp_dir)
+                        self.assertEqual(data, 'this is the content')
 
     def test_extract_gzip(self):
-        temp_dir = tempfile.mkdtemp()
+        with get_tmp_dir() as temp_dir:
             with tempfile.NamedTemporaryFile(suffix='.gz') as f:
                 with gzip.GzipFile(f.name, 'wb') as zf:
                     zf.write('this is the content'.encode())
                 utils.extract_archive(f.name, temp_dir)
                 f_name = os.path.join(temp_dir, os.path.splitext(os.path.basename(f.name))[0])
-            assert os.path.exists(f_name)
+                self.assertTrue(os.path.exists(f_name))
                 with open(os.path.join(f_name), 'r') as nf:
                     data = nf.read()
-            assert data == 'this is the content', data
-        shutil.rmtree(temp_dir)
+                self.assertEqual(data, 'this is the content')
 
 
 if __name__ == '__main__':

test/test_transforms.py

 from __future__ import division
+import os
 import torch
 import torchvision.transforms as transforms
 import torchvision.transforms.functional as F
@@ -18,7 +19,8 @@ try:
 except ImportError:
     stats = None
 
-GRACE_HOPPER = get_file_path_2('assets/grace_hopper_517x606.jpg')
+GRACE_HOPPER = get_file_path_2(
+    os.path.dirname(os.path.abspath(__file__)), 'assets', 'grace_hopper_517x606.jpg')
 
 
 class Tester(unittest.TestCase):