Refine typing of conditional imports

Using ModuleType is a little heavy-handed. Avoiding it, a lighter
touch, better preserves information about the optional modules.

nose2/plugins/loader/eggdiscovery.py

@@ -17,7 +17,6 @@
 
 import logging
 import os
-import types
 
 from nose2 import events
 from nose2.plugins.loader import discovery
@@ -26,11 +25,11 @@
 log = logging.getLogger(__name__)
 
 try:
-    import pkg_resources as _pkg_resources_mod
+    import pkg_resources
 
-    pkg_resources: types.ModuleType | None = _pkg_resources_mod
+    _has_pkg_resources = True
 except ImportError:
-    pkg_resources = None
+    _has_pkg_resources = False
 
 
 class EggDiscoveryLoader(events.Plugin, discovery.Discoverer):
@@ -85,7 +84,7 @@ def _find_tests_in_egg_dir(self, event, rel_path, dist):
     def _find_tests_in_dir(self, event, full_path, top_level):
         if os.path.exists(full_path):
             return
-        elif pkg_resources and full_path.find(".egg") != -1:
+        elif _has_pkg_resources and full_path.find(".egg") != -1:
             egg_path = full_path.split(".egg")[0] + ".egg"
             for dist in pkg_resources.find_distributions(egg_path):
                 for modname in dist._get_metadata("top_level.txt"):

nose2/tests/functional/test_eggdiscovery_loader.py

@@ -6,11 +6,9 @@
 from nose2.tests._common import FunctionalTestCase, support_file
 
 try:
-    import pkg_resources
-
+    import pkg_resources  # noqa: F401
 except ImportError:
-    pkg_resources = None
-
+    pass
 else:
 
     class EggDiscoveryFunctionalTest(FunctionalTestCase):