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

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

Lib/test/test_importlib/test_metadata_api.py

@@ -0,0 +1,151 @@
+import re
+import textwrap
+import unittest
+import itertools
+
+from collections.abc import Iterator
+
+from . import fixtures
+from importlib.metadata import (
+    Distribution, PackageNotFoundError, distribution,
+    entry_points, files, metadata, requires, version,
+    )
+
+
+class APITests(
+        fixtures.EggInfoPkg,
+        fixtures.DistInfoPkg,
+        fixtures.EggInfoFile,
+        unittest.TestCase):
+
+    version_pattern = r'\d+\.\d+(\.\d)?'
+
+    def test_retrieves_version_of_self(self):
+        pkg_version = version('egginfo-pkg')
+        assert isinstance(pkg_version, str)
+        assert re.match(self.version_pattern, pkg_version)
+
+    def test_retrieves_version_of_distinfo_pkg(self):
+        pkg_version = version('distinfo-pkg')
+        assert isinstance(pkg_version, str)
+        assert re.match(self.version_pattern, pkg_version)
+
+    def test_for_name_does_not_exist(self):
+        with self.assertRaises(PackageNotFoundError):
+            distribution('does-not-exist')
+
+    def test_for_top_level(self):
+        self.assertEqual(
+            distribution('egginfo-pkg').read_text('top_level.txt').strip(),
+            'mod')
+
+    def test_read_text(self):
+        top_level = [
+            path for path in files('egginfo-pkg')
+            if path.name == 'top_level.txt'
+            ][0]
+        self.assertEqual(top_level.read_text(), 'mod\n')
+
+    def test_entry_points(self):
+        entries = dict(entry_points()['entries'])
+        ep = entries['main']
+        self.assertEqual(ep.value, 'mod:main')
+        self.assertEqual(ep.extras, [])
+
+    def test_metadata_for_this_package(self):
+        md = metadata('egginfo-pkg')
+        assert md['author'] == 'Steven Ma'
+        assert md['LICENSE'] == 'Unknown'
+        assert md['Name'] == 'egginfo-pkg'
+        classifiers = md.get_all('Classifier')
+        assert 'Topic :: Software Development :: Libraries' in classifiers
+
+    @staticmethod
+    def _test_files(files_iter):
+        assert isinstance(files_iter, Iterator), files_iter
+        files = list(files_iter)
+        root = files[0].root
+        for file in files:
+            assert file.root == root
+            assert not file.hash or file.hash.value
+            assert not file.hash or file.hash.mode == 'sha256'
+            assert not file.size or file.size >= 0
+            assert file.locate().exists()
+            assert isinstance(file.read_binary(), bytes)
+            if file.name.endswith('.py'):
+                file.read_text()
+
+    def test_file_hash_repr(self):
+        assertRegex = self.assertRegex
+
+        util = [
+            p for p in files('distinfo-pkg')
+            if p.name == 'mod.py'
+            ][0]
+        assertRegex(
+            repr(util.hash),
+            '<FileHash mode: sha256 value: .*>')
+
+    def test_files_dist_info(self):
+        self._test_files(files('distinfo-pkg'))
+
+    def test_files_egg_info(self):
+        self._test_files(files('egginfo-pkg'))
+
+    def test_version_egg_info_file(self):
+        self.assertEqual(version('egginfo-file'), '0.1')
+
+    def test_requires_egg_info_file(self):
+        requirements = requires('egginfo-file')
+        self.assertIsNone(requirements)
+
+    def test_requires(self):
+        deps = requires('egginfo-pkg')
+        assert any(
+            dep == 'wheel >= 1.0; python_version >= "2.7"'
+            for dep in deps
+            )
+
+    def test_requires_dist_info(self):
+        deps = list(requires('distinfo-pkg'))
+        assert deps and all(deps)
+
+    def test_more_complex_deps_requires_text(self):
+        requires = textwrap.dedent("""
+            dep1
+            dep2
+
+            [:python_version < "3"]
+            dep3
+
+            [extra1]
+            dep4
+
+            [extra2:python_version < "3"]
+            dep5
+            """)
+        deps = sorted(Distribution._deps_from_requires_text(requires))
+        expected = [
+            'dep1',
+            'dep2',
+            'dep3; python_version < "3"',
+            'dep4; extra == "extra1"',
+            'dep5; (python_version < "3") and extra == "extra2"',
+            ]
+        # It's important that the environment marker expression be
+        # wrapped in parentheses to avoid the following 'and' binding more
+        # tightly than some other part of the environment expression.
+
+        assert deps == expected
+
+
+class OffSysPathTests(fixtures.DistInfoPkgOffPath, unittest.TestCase):
+    def test_find_distributions_specified_path(self):
+        dists = itertools.chain.from_iterable(
+            resolver(path=[str(self.site_dir)])
+            for resolver in Distribution._discover_resolvers()
+            )
+        assert any(
+            dist.metadata['Name'] == 'distinfo-pkg'
+            for dist in dists
+            )