postgresql_ext: fix module's failing when available ext versions contain a pure string (#1099)

* postgresql_ext: fix module's failing when available ext versions contain a pure string

* Add unit tests

* Add changelog fragment

* fix

tests/integration/targets/postgresql_ext/tasks/postgresql_ext_version_opt.yml

@@ -330,6 +330,23 @@
       - result.failed == true
       - result.msg == "Extension non_existent is not installed"
 
+  ######################################################################
+  # https://github.com/ansible-collections/community.general/issues/1095
+  - name: Install postgis
+    package:
+      name: postgis
+
+  - name: Create postgis extension
+    <<: *task_parameters
+    postgresql_ext:
+      <<: *pg_parameters
+      name: postgis
+      version: latest
+
+  - assert:
+      that:
+      - result is changed
+
   # Cleanup:
   - name: postgresql_ext_version - drop the extension
     <<: *task_parameters

tests/unit/plugins/modules/database/postgresql/test_postgresql_ext.py

@@ -0,0 +1,35 @@
+# Copyright 2020, Andrew Klychkov @Andersson007 <aaklychkov@mail.ru>
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+import pytest
+
+from ansible_collections.community.general.plugins.modules.database.postgresql.postgresql_ext import (
+    parse_ext_versions,
+)
+
+
+@pytest.mark.parametrize(
+    'current,test_input,expected',
+    [
+        (
+            '2.0.0',
+            [{'version': '3.1.0dev'}, {'version': '3.1.0devnext'}, {'version': 'unpackaged'}],
+            ['3.1.0dev', '3.1.0devnext'],
+        ),
+        (
+            '2.0.0',
+            [{'version': 'unpackaged'}, {'version': '3.1.0dev'}, {'version': '3.1.0devnext'}],
+            ['3.1.0dev', '3.1.0devnext'],
+        ),
+        (
+            '2.0.1',
+            [{'version': 'unpackaged'}, {'version': '2.0.0'}, {'version': '2.1.0dev'}],
+            ['2.1.0dev'],
+        ),
+    ]
+)
+def test_parse_ext_versions(current, test_input, expected):
+    assert parse_ext_versions(current, test_input) == expected