bpo-42129: Add support for resources in namespaces (GH-24670)

* Unify behavior in ResourceReaderDefaultsTests and align with the behavior found in importlib_resources.
* Equip NamespaceLoader with a NamespaceReader.
* Apply changes from importlib_resources 5.0.4

1 files changed, 123 insertions, 0 deletions

diff --git a/Lib/test/test_importlib/test_reader.py b/Lib/test/test_importlib/test_reader.py
new file mode 100644
index 0000000000..905d4fcdec
--- /dev/null
+++ b/Lib/test/test_importlib/test_reader.py
@@ -0,0 +1,123 @@
+import os.path
+import sys
+import pathlib
+import unittest
+
+from importlib import import_module
+from importlib.readers import MultiplexedPath, NamespaceReader
+
+
+class MultiplexedPathTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        path = pathlib.Path(__file__).parent / 'namespacedata01'
+        cls.folder = str(path)
+
+    def test_init_no_paths(self):
+        with self.assertRaises(FileNotFoundError):
+            MultiplexedPath()
+
+    def test_init_file(self):
+        with self.assertRaises(NotADirectoryError):
+            MultiplexedPath(os.path.join(self.folder, 'binary.file'))
+
+    def test_iterdir(self):
+        contents = {path.name for path in MultiplexedPath(self.folder).iterdir()}
+        try:
+            contents.remove('__pycache__')
+        except (KeyError, ValueError):
+            pass
+        self.assertEqual(contents, {'binary.file', 'utf-16.file', 'utf-8.file'})
+
+    def test_iterdir_duplicate(self):
+        data01 = os.path.abspath(os.path.join(__file__, '..', 'data01'))
+        contents = {
+            path.name for path in MultiplexedPath(self.folder, data01).iterdir()
+        }
+        for remove in ('__pycache__', '__init__.pyc'):
+            try:
+                contents.remove(remove)
+            except (KeyError, ValueError):
+                pass
+        self.assertEqual(
+            contents,
+            {'__init__.py', 'binary.file', 'subdirectory', 'utf-16.file', 'utf-8.file'},
+        )
+
+    def test_is_dir(self):
+        self.assertEqual(MultiplexedPath(self.folder).is_dir(), True)
+
+    def test_is_file(self):
+        self.assertEqual(MultiplexedPath(self.folder).is_file(), False)
+
+    def test_open_file(self):
+        path = MultiplexedPath(self.folder)
+        with self.assertRaises(FileNotFoundError):
+            path.read_bytes()
+        with self.assertRaises(FileNotFoundError):
+            path.read_text()
+        with self.assertRaises(FileNotFoundError):
+            path.open()
+
+    def test_join_path(self):
+        print('test_join_path')
+        prefix = os.path.abspath(os.path.join(__file__, '..'))
+        data01 = os.path.join(prefix, 'data01')
+        path = MultiplexedPath(self.folder, data01)
+        self.assertEqual(
+            str(path.joinpath('binary.file'))[len(prefix) + 1 :],
+            os.path.join('namespacedata01', 'binary.file'),
+        )
+        self.assertEqual(
+            str(path.joinpath('subdirectory'))[len(prefix) + 1 :],
+            os.path.join('data01', 'subdirectory'),
+        )
+        self.assertEqual(
+            str(path.joinpath('imaginary'))[len(prefix) + 1 :],
+            os.path.join('namespacedata01', 'imaginary'),
+        )
+
+    def test_repr(self):
+        self.assertEqual(
+            repr(MultiplexedPath(self.folder)),
+            "MultiplexedPath('{}')".format(self.folder),
+        )
+
+
+class NamespaceReaderTest(unittest.TestCase):
+    site_dir = str(pathlib.Path(__file__).parent)
+
+    @classmethod
+    def setUpClass(cls):
+        sys.path.append(cls.site_dir)
+
+    @classmethod
+    def tearDownClass(cls):
+        sys.path.remove(cls.site_dir)
+
+    def test_init_error(self):
+        with self.assertRaises(ValueError):
+            NamespaceReader(['path1', 'path2'])
+
+    def test_resource_path(self):
+        namespacedata01 = import_module('namespacedata01')
+        reader = NamespaceReader(namespacedata01.__spec__.submodule_search_locations)
+
+        root = os.path.abspath(os.path.join(__file__, '..', 'namespacedata01'))
+        self.assertEqual(
+            reader.resource_path('binary.file'), os.path.join(root, 'binary.file')
+        )
+        self.assertEqual(
+            reader.resource_path('imaginary'), os.path.join(root, 'imaginary')
+        )
+
+    def test_files(self):
+        namespacedata01 = import_module('namespacedata01')
+        reader = NamespaceReader(namespacedata01.__spec__.submodule_search_locations)
+        root = os.path.abspath(os.path.join(__file__, '..', 'namespacedata01'))
+        self.assertIsInstance(reader.files(), MultiplexedPath)
+        self.assertEqual(repr(reader.files()), "MultiplexedPath('{}')".format(root))
+
+
+if __name__ == '__main__':
+    unittest.main()