Unit tests: share common code (#31456)

* move set_module_args to units.modules.utils
* unit tests: reuse set_module_args
* unit tests: mock exit/fail_json in module.utils.ModuleTestCase
* unit tests: use module.utils.ModuleTestCase
* unit tests: fix 'import shadowed by loop variable'

test/units/modules/utils.py

@@ -0,0 +1,38 @@
+import json
+
+from ansible.compat.tests import unittest
+from ansible.compat.tests.mock import patch
+from ansible.module_utils import basic
+from ansible.module_utils._text import to_bytes
+
+
+def set_module_args(args):
+    args = json.dumps({'ANSIBLE_MODULE_ARGS': args})
+    basic._ANSIBLE_ARGS = to_bytes(args)
+
+
+class AnsibleExitJson(Exception):
+    pass
+
+
+class AnsibleFailJson(Exception):
+    pass
+
+
+def exit_json(*args, **kwargs):
+    if 'changed' not in kwargs:
+        kwargs['changed'] = False
+    raise AnsibleExitJson(kwargs)
+
+
+def fail_json(*args, **kwargs):
+    kwargs['failed'] = True
+    raise AnsibleFailJson(kwargs)
+
+
+class ModuleTestCase(unittest.TestCase):
+
+    def setUp(self):
+        self.mock_module = patch.multiple(basic.AnsibleModule, exit_json=exit_json, fail_json=fail_json)
+        self.mock_module.start()
+        self.addCleanup(self.mock_module.stop)