[stable-2.12] ansible-test - Fix import test for collections.

(cherry picked from commit e56e47faa7)

Co-authored-by: Matt Clay <matt@mystile.com>

changelogs/fragments/ansible-test-import-collections.yml

@@ -0,0 +1,5 @@
+bugfixes:
+  - ansible-test - The ``import`` sanity test no longer reports errors about ``packaging`` being missing when testing collections.
+minor_changes:
+  - The collection loader now reports a Python warning if an attempt is made to install the Ansible collection loader a second time.
+    Previously this condition was reported using an Ansible warning.

lib/ansible/plugins/loader.py

@@ -1147,7 +1147,8 @@ def _does_collection_support_ansible_version(requirement_string, ansible_version
 
 def _configure_collection_loader():
     if AnsibleCollectionConfig.collection_finder:
-        display.warning('AnsibleCollectionFinder has already been configured')
+        # this must be a Python warning so that it can be filtered out by the import sanity test
+        warnings.warn('AnsibleCollectionFinder has already been configured')
         return
 
     finder = _AnsibleCollectionFinder(C.config.get_config_value('COLLECTIONS_PATHS'), C.config.get_config_value('COLLECTIONS_SCAN_SYS_PATH'))

test/integration/targets/ansible-test/ansible_collections/ns/col/plugins/lookup/vendor1.py

@@ -15,6 +15,8 @@ EXAMPLES = '''#'''
 RETURN = '''#'''
 
 from ansible.plugins.lookup import LookupBase
+# noinspection PyUnresolvedReferences
+from ansible.plugins import loader  # import the loader to verify it works when the collection loader has already been loaded
 
 try:
     import demo

test/integration/targets/ansible-test/ansible_collections/ns/col/plugins/lookup/vendor2.py

@@ -15,6 +15,8 @@ EXAMPLES = '''#'''
 RETURN = '''#'''
 
 from ansible.plugins.lookup import LookupBase
+# noinspection PyUnresolvedReferences
+from ansible.plugins import loader  # import the loader to verify it works when the collection loader has already been loaded
 
 try:
     import demo

test/lib/ansible_test/_util/target/sanity/import/importer.py

@@ -121,8 +121,13 @@ def main():
         # do not support collection loading when not testing a collection
         collection_loader = None
 
-    # remove all modules under the ansible package, except the preloaded vendor module
-    list(map(sys.modules.pop, [m for m in sys.modules if m.partition('.')[0] == ansible.__name__ and m != vendor_module_name]))
+    if collection_loader and import_type == 'plugin':
+        # do not unload ansible code for collection plugin (not module) tests
+        # doing so could result in the collection loader being initialized multiple times
+        pass
+    else:
+        # remove all modules under the ansible package, except the preloaded vendor module
+        list(map(sys.modules.pop, [m for m in sys.modules if m.partition('.')[0] == ansible.__name__ and m != vendor_module_name]))
 
     if import_type == 'module':
         # pre-load an empty ansible package to prevent unwanted code in __init__.py from loading
@@ -444,7 +449,7 @@ def main():
         try:
             yield
         finally:
-            if import_type == 'plugin':
+            if import_type == 'plugin' and not collection_loader:
                 from ansible.utils.collection_loader._collection_finder import _AnsibleCollectionFinder
                 _AnsibleCollectionFinder._remove()  # pylint: disable=protected-access
 
@@ -493,6 +498,11 @@ def main():
         with warnings.catch_warnings():
             warnings.simplefilter('error')
 
+            if collection_loader and import_type == 'plugin':
+                warnings.filterwarnings(
+                    "ignore",
+                    "AnsibleCollectionFinder has already been configured")
+
             if sys.version_info[0] == 2:
                 warnings.filterwarnings(
                     "ignore",