#13 fix regression from mangling sys.modules

Author: reverbc

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Changelog
 
 ## [Unreleased]
+## Fixed
+- Fix #13 regression caused by mangling `sys.modules`
 
 ## [1.0.2] - 2021-03-10
 ### Fixed

pylint_pytest/checkers/fixture.py

@@ -72,25 +72,20 @@ def visit_module(self, node):
                 # run pytest session with customized plugin to collect fixtures
                 fixture_collector = FixtureCollector()
 
-                # save and remove modules imported by pytest to prevent pytest warning during fixture collection:
-                # <PytestAssertRewriteWarning: Module already imported so cannot be rewritten>
-                sys_mods = set(sys.modules.keys())
-
                 # save and restore sys.path to prevent pytest.main from altering it
                 sys_path = sys.path.copy()
 
                 pytest.main(
-                    [node.file, '--fixtures', '--collect-only'],
+                    [
+                        node.file, '--fixtures', '--collect-only',
+                        '--pythonwarnings=ignore:Module already imported:pytest.PytestWarning',
+                    ],
                     plugins=[fixture_collector],
                 )
 
                 # restore sys.path
                 sys.path = sys_path
 
-                # unload modules imported by pytest.main
-                for module in set(sys.modules.keys()) - sys_mods:
-                    del sys.modules[module]
-
                 FixtureChecker._pytest_fixtures = fixture_collector.fixtures
         finally:
             # restore output devices

tests/base_tester.py

@@ -1,5 +1,7 @@
 import sys
 import os
+from pprint import pprint
+
 import astroid
 from pylint.testutils import UnittestLinter
 try:
@@ -45,6 +47,7 @@ def verify_messages(self, msg_count, msg_id=None):
             if message.msg_id == msg_id:
                 matched_count += 1
 
+        pprint(self.MESSAGES)
         assert matched_count == msg_count, f'expecting {msg_count}, actual {matched_count}'
 
     def setup_method(self):