bpo-34632: Add importlib.metadata (GH-12547)

Add importlib.metadata module as forward port of the standalone importlib_metadata.

Lib/test/test_importlib/test_main.py

@@ -0,0 +1,158 @@
+# coding: utf-8
+
+import re
+import textwrap
+import unittest
+import importlib.metadata
+
+from . import fixtures
+from importlib.metadata import (
+    Distribution, EntryPoint,
+    PackageNotFoundError, distributions,
+    entry_points, metadata, version,
+    )
+
+
+class BasicTests(fixtures.DistInfoPkg, unittest.TestCase):
+    version_pattern = r'\d+\.\d+(\.\d)?'
+
+    def test_retrieves_version_of_self(self):
+        dist = Distribution.from_name('distinfo-pkg')
+        assert isinstance(dist.version, str)
+        assert re.match(self.version_pattern, dist.version)
+
+    def test_for_name_does_not_exist(self):
+        with self.assertRaises(PackageNotFoundError):
+            Distribution.from_name('does-not-exist')
+
+    def test_new_style_classes(self):
+        self.assertIsInstance(Distribution, type)
+
+
+class ImportTests(fixtures.DistInfoPkg, unittest.TestCase):
+    def test_import_nonexistent_module(self):
+        # Ensure that the MetadataPathFinder does not crash an import of a
+        # non-existant module.
+        with self.assertRaises(ImportError):
+            importlib.import_module('does_not_exist')
+
+    def test_resolve(self):
+        entries = dict(entry_points()['entries'])
+        ep = entries['main']
+        self.assertEqual(ep.load().__name__, "main")
+
+    def test_resolve_without_attr(self):
+        ep = EntryPoint(
+            name='ep',
+            value='importlib.metadata',
+            group='grp',
+            )
+        assert ep.load() is importlib.metadata
+
+
+class NameNormalizationTests(
+        fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
+    @staticmethod
+    def pkg_with_dashes(site_dir):
+        """
+        Create minimal metadata for a package with dashes
+        in the name (and thus underscores in the filename).
+        """
+        metadata_dir = site_dir / 'my_pkg.dist-info'
+        metadata_dir.mkdir()
+        metadata = metadata_dir / 'METADATA'
+        with metadata.open('w') as strm:
+            strm.write('Version: 1.0\n')
+        return 'my-pkg'
+
+    def test_dashes_in_dist_name_found_as_underscores(self):
+        """
+        For a package with a dash in the name, the dist-info metadata
+        uses underscores in the name. Ensure the metadata loads.
+        """
+        pkg_name = self.pkg_with_dashes(self.site_dir)
+        assert version(pkg_name) == '1.0'
+
+    @staticmethod
+    def pkg_with_mixed_case(site_dir):
+        """
+        Create minimal metadata for a package with mixed case
+        in the name.
+        """
+        metadata_dir = site_dir / 'CherryPy.dist-info'
+        metadata_dir.mkdir()
+        metadata = metadata_dir / 'METADATA'
+        with metadata.open('w') as strm:
+            strm.write('Version: 1.0\n')
+        return 'CherryPy'
+
+    def test_dist_name_found_as_any_case(self):
+        """
+        Ensure the metadata loads when queried with any case.
+        """
+        pkg_name = self.pkg_with_mixed_case(self.site_dir)
+        assert version(pkg_name) == '1.0'
+        assert version(pkg_name.lower()) == '1.0'
+        assert version(pkg_name.upper()) == '1.0'
+
+
+class NonASCIITests(fixtures.OnSysPath, fixtures.SiteDir, unittest.TestCase):
+    @staticmethod
+    def pkg_with_non_ascii_description(site_dir):
+        """
+        Create minimal metadata for a package with non-ASCII in
+        the description.
+        """
+        metadata_dir = site_dir / 'portend.dist-info'
+        metadata_dir.mkdir()
+        metadata = metadata_dir / 'METADATA'
+        with metadata.open('w', encoding='utf-8') as fp:
+            fp.write('Description: pôrˈtend\n')
+        return 'portend'
+
+    @staticmethod
+    def pkg_with_non_ascii_description_egg_info(site_dir):
+        """
+        Create minimal metadata for an egg-info package with
+        non-ASCII in the description.
+        """
+        metadata_dir = site_dir / 'portend.dist-info'
+        metadata_dir.mkdir()
+        metadata = metadata_dir / 'METADATA'
+        with metadata.open('w', encoding='utf-8') as fp:
+            fp.write(textwrap.dedent("""
+                Name: portend
+
+                pôrˈtend
+                """).lstrip())
+        return 'portend'
+
+    def test_metadata_loads(self):
+        pkg_name = self.pkg_with_non_ascii_description(self.site_dir)
+        meta = metadata(pkg_name)
+        assert meta['Description'] == 'pôrˈtend'
+
+    def test_metadata_loads_egg_info(self):
+        pkg_name = self.pkg_with_non_ascii_description_egg_info(self.site_dir)
+        meta = metadata(pkg_name)
+        assert meta.get_payload() == 'pôrˈtend\n'
+
+
+class DiscoveryTests(fixtures.EggInfoPkg,
+                     fixtures.DistInfoPkg,
+                     unittest.TestCase):
+
+    def test_package_discovery(self):
+        dists = list(distributions())
+        assert all(
+            isinstance(dist, Distribution)
+            for dist in dists
+            )
+        assert any(
+            dist.metadata['Name'] == 'egginfo-pkg'
+            for dist in dists
+            )
+        assert any(
+            dist.metadata['Name'] == 'distinfo-pkg'
+            for dist in dists
+            )