Support zip files for open()

importlib_resources/__init__.py

@@ -48,16 +48,18 @@ def open(package: Package, file_name: FileName) -> BinaryIO:
     package = _get_package(package)
     package_path = os.path.dirname(os.path.abspath(package.__spec__.origin))
     full_path = os.path.join(package_path, file_name)
-    if not os.path.exists(full_path):
-        package_name = package.__spec__.name
-        message = "{!r} does not exist"
-        raise FileNotFoundError(message.format(full_path))
     # Just assume the loader is a resource loader; all the relevant
     # importlib.machinery loaders are and an AttributeError for get_data() will
     # make it clear what is needed from the loader.
     loader = typing.cast(importlib.abc.ResourceLoader, package.__spec__.loader)
-    data = loader.get_data(full_path)
-    return io.BytesIO(data)
+    try:
+        data = loader.get_data(full_path)
+    except OSError:
+        package_name = package.__spec__.name
+        message = f'{file_name!r} resource not found in {package_name!r}'
+        raise FileNotFoundError(message)
+    else:
+        return io.BytesIO(data)
 
 
 def read(package: Package, file_name: FileName, encoding: str = 'utf-8',

importlib_resources/tests/test_open.py

@@ -8,6 +8,27 @@
 from importlib_resources.tests import data
 
 
+ZIP_DATA_PATH = None  # type: Optional[pathlib.Path]
+zip_data = None  # type: Optional[]
+def setUpModule():
+    global ZIP_DATA_PATH, zip_data
+    data_path = pathlib.Path(data.__spec__.origin)
+    data_dir = data_path.parent
+    ZIP_DATA_PATH = data_dir / 'ziptestdata.zip'
+    sys.path.append(str(ZIP_DATA_PATH))
+    import ziptestdata
+    zip_data = ziptestdata
+
+
+def tearDownModule():
+    global zip_data
+    del zip_data
+    try:
+        sys.path.remove(str(ZIP_DATA_PATH))
+    except ValueError:
+        pass
+
+
 class CommonTests(unittest.TestCase):
 
     def test_package_name(self):
@@ -60,19 +81,38 @@ def test_non_package(self):
                 pass
 
 
-class OpenTests(unittest.TestCase):
+class OpenTests:
+
+    # Subclasses are expected to set the 'data' attribute.
 
     def test_opened_for_reading(self):
         # The file-like object is ready for reading.
-        with resources.open(data, 'utf-8.file') as file:
+        with resources.open(self.data, 'utf-8.file') as file:
             self.assertEqual(b"Hello, UTF-8 world!\n", file.read())
 
     def test_wrap_for_text(self):
         # The file-like object can be wrapped for text reading.
-        with resources.open(data, 'utf-8.file') as file:
+        with resources.open(self.data, 'utf-8.file') as file:
             text_file = io.TextIOWrapper(file, encoding='utf-8')
             self.assertEqual('Hello, UTF-8 world!\n', text_file.read())
 
+    def test_FileNotFoundError(self):
+        with self.assertRaises(FileNotFoundError):
+            with resources.open(self.data, 'does-not-exist') as file:
+                pass
+
+
+class OpenDiskTests(OpenTests, unittest.TestCase):
+
+    def setUp(self):
+        self.data = data
+
+
+class OpenZipTests(OpenTests, unittest.TestCase):
+
+    def setUp(self):
+        self.data = zip_data
+
 
 if __name__ == '__main__':
     unittest.main()