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

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

Lib/test/test_importlib/fixtures.py

@@ -0,0 +1,199 @@
+from __future__ import unicode_literals
+
+import os
+import sys
+import shutil
+import tempfile
+import textwrap
+import contextlib
+
+try:
+    from contextlib import ExitStack
+except ImportError:
+    from contextlib2 import ExitStack
+
+try:
+    import pathlib
+except ImportError:
+    import pathlib2 as pathlib
+
+
+__metaclass__ = type
+
+
+@contextlib.contextmanager
+def tempdir():
+    tmpdir = tempfile.mkdtemp()
+    try:
+        yield pathlib.Path(tmpdir)
+    finally:
+        shutil.rmtree(tmpdir)
+
+
+@contextlib.contextmanager
+def save_cwd():
+    orig = os.getcwd()
+    try:
+        yield
+    finally:
+        os.chdir(orig)
+
+
+@contextlib.contextmanager
+def tempdir_as_cwd():
+    with tempdir() as tmp:
+        with save_cwd():
+            os.chdir(str(tmp))
+            yield tmp
+
+
+class SiteDir:
+    def setUp(self):
+        self.fixtures = ExitStack()
+        self.addCleanup(self.fixtures.close)
+        self.site_dir = self.fixtures.enter_context(tempdir())
+
+
+class OnSysPath:
+    @staticmethod
+    @contextlib.contextmanager
+    def add_sys_path(dir):
+        sys.path[:0] = [str(dir)]
+        try:
+            yield
+        finally:
+            sys.path.remove(str(dir))
+
+    def setUp(self):
+        super(OnSysPath, self).setUp()
+        self.fixtures.enter_context(self.add_sys_path(self.site_dir))
+
+
+class DistInfoPkg(OnSysPath, SiteDir):
+    files = {
+        "distinfo_pkg-1.0.0.dist-info": {
+            "METADATA": """
+                Name: distinfo-pkg
+                Author: Steven Ma
+                Version: 1.0.0
+                Requires-Dist: wheel >= 1.0
+                Requires-Dist: pytest; extra == 'test'
+                """,
+            "RECORD": "mod.py,sha256=abc,20\n",
+            "entry_points.txt": """
+                [entries]
+                main = mod:main
+            """
+            },
+        "mod.py": """
+            def main():
+                print("hello world")
+            """,
+        }
+
+    def setUp(self):
+        super(DistInfoPkg, self).setUp()
+        build_files(DistInfoPkg.files, self.site_dir)
+
+
+class DistInfoPkgOffPath(SiteDir):
+    def setUp(self):
+        super(DistInfoPkgOffPath, self).setUp()
+        build_files(DistInfoPkg.files, self.site_dir)
+
+
+class EggInfoPkg(OnSysPath, SiteDir):
+    files = {
+        "egginfo_pkg.egg-info": {
+            "PKG-INFO": """
+                Name: egginfo-pkg
+                Author: Steven Ma
+                License: Unknown
+                Version: 1.0.0
+                Classifier: Intended Audience :: Developers
+                Classifier: Topic :: Software Development :: Libraries
+                """,
+            "SOURCES.txt": """
+                mod.py
+                egginfo_pkg.egg-info/top_level.txt
+            """,
+            "entry_points.txt": """
+                [entries]
+                main = mod:main
+            """,
+            "requires.txt": """
+                wheel >= 1.0; python_version >= "2.7"
+                [test]
+                pytest
+            """,
+            "top_level.txt": "mod\n"
+            },
+        "mod.py": """
+            def main():
+                print("hello world")
+            """,
+        }
+
+    def setUp(self):
+        super(EggInfoPkg, self).setUp()
+        build_files(EggInfoPkg.files, prefix=self.site_dir)
+
+
+class EggInfoFile(OnSysPath, SiteDir):
+    files = {
+        "egginfo_file.egg-info": """
+            Metadata-Version: 1.0
+            Name: egginfo_file
+            Version: 0.1
+            Summary: An example package
+            Home-page: www.example.com
+            Author: Eric Haffa-Vee
+            Author-email: eric@example.coms
+            License: UNKNOWN
+            Description: UNKNOWN
+            Platform: UNKNOWN
+            """,
+        }
+
+    def setUp(self):
+        super(EggInfoFile, self).setUp()
+        build_files(EggInfoFile.files, prefix=self.site_dir)
+
+
+def build_files(file_defs, prefix=pathlib.Path()):
+    """Build a set of files/directories, as described by the
+
+    file_defs dictionary.  Each key/value pair in the dictionary is
+    interpreted as a filename/contents pair.  If the contents value is a
+    dictionary, a directory is created, and the dictionary interpreted
+    as the files within it, recursively.
+
+    For example:
+
+    {"README.txt": "A README file",
+     "foo": {
+        "__init__.py": "",
+        "bar": {
+            "__init__.py": "",
+        },
+        "baz.py": "# Some code",
+     }
+    }
+    """
+    for name, contents in file_defs.items():
+        full_name = prefix / name
+        if isinstance(contents, dict):
+            full_name.mkdir()
+            build_files(contents, prefix=full_name)
+        else:
+            if isinstance(contents, bytes):
+                with full_name.open('wb') as f:
+                    f.write(contents)
+            else:
+                with full_name.open('w') as f:
+                    f.write(DALS(contents))
+
+
+def DALS(str):
+    "Dedent and left-strip"
+    return textwrap.dedent(str).lstrip()