Extract ZipFixtures

Author: jaraco

tests/fixtures.py

@@ -10,6 +10,14 @@
 from .py39compat import FS_NONASCII
 from typing import Dict, Union
 
+try:
+    from importlib import resources
+
+    getattr(resources, 'files')
+    getattr(resources, 'as_file')
+except (ImportError, AttributeError):
+    import importlib_resources as resources  # type: ignore
+
 
 @contextlib.contextmanager
 def tempdir():
@@ -285,3 +293,20 @@ def DALS(str):
 class NullFinder:
     def find_module(self, name):
         pass
+
+
+class ZipFixtures:
+    root = 'tests.data'
+
+    def _fixture_on_path(self, filename):
+        pkg_file = resources.files(self.root).joinpath(filename)
+        file = self.resources.enter_context(resources.as_file(pkg_file))
+        assert file.name.startswith('example-'), file.name
+        sys.path.insert(0, str(file))
+        self.resources.callback(sys.path.pop, 0)
+
+    def setUp(self):
+        # Add self.zip_name to the front of sys.path.
+        self.resources = contextlib.ExitStack()
+        self.addCleanup(self.resources.close)
+        self._fixture_on_path(self.zip_name)

tests/test_zip.py

@@ -1,7 +1,7 @@
 import sys
 import unittest
 
-from contextlib import ExitStack
+from . import fixtures
 from importlib_metadata import (
     PackageNotFoundError,
     distribution,
@@ -11,31 +11,9 @@
     version,
 )
 
-try:
-    from importlib import resources
 
-    getattr(resources, 'files')
-    getattr(resources, 'as_file')
-except (ImportError, AttributeError):
-    import importlib_resources as resources  # type: ignore
-
-
-class TestZip(unittest.TestCase):
-    root = 'tests.data'
-
-    def _fixture_on_path(self, filename):
-        pkg_file = resources.files(self.root).joinpath(filename)
-        file = self.resources.enter_context(resources.as_file(pkg_file))
-        assert file.name.startswith('example-'), file.name
-        sys.path.insert(0, str(file))
-        self.resources.callback(sys.path.pop, 0)
-
-    def setUp(self):
-        # Find the path to the example-*.whl so we can add it to the front of
-        # sys.path, where we'll then try to find the metadata thereof.
-        self.resources = ExitStack()
-        self.addCleanup(self.resources.close)
-        self._fixture_on_path('example-21.12-py3-none-any.whl')
+class TestZip(fixtures.ZipFixtures, unittest.TestCase):
+    zip_name = 'example-21.12-py3-none-any.whl'
 
     def test_zip_version(self):
         self.assertEqual(version('example'), '21.12')
@@ -68,12 +46,7 @@ def test_one_distribution(self):
 
 
 class TestEgg(TestZip):
-    def setUp(self):
-        # Find the path to the example-*.egg so we can add it to the front of
-        # sys.path, where we'll then try to find the metadata thereof.
-        self.resources = ExitStack()
-        self.addCleanup(self.resources.close)
-        self._fixture_on_path('example-21.12-py3.6.egg')
+    zip_name = 'example-21.12-py3.6.egg'
 
     def test_files(self):
         for file in files('example'):