[last PR stuff] + Add warning if configs specified in 2 params (#5)

* Lean on API validation for tower_inventory_source arg errors

used for
 - validating needed credential is given
 - missing source_project for scm sources

* Add warning when config is specified in 2 places

Fix up unit tests, address multiple comments re: backwards compatibility, redundant methods, etc.

Update new_name and variables parameters, update unit tests

awx_collection/test/awx/test_module_utils.py

@@ -0,0 +1,35 @@
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+import sys
+
+from unittest import mock
+
+import json
+
+
+def test_duplicate_config(collection_import):
+    # imports done here because of PATH issues unique to this test suite
+    TowerModule = collection_import('plugins.module_utils.tower_api').TowerModule
+    data = {
+        'name': 'zigzoom',
+        'zig': 'zoom',
+        'tower_username': 'bob',
+        'tower_config_file': 'my_config'
+    }
+    cli_data = {'ANSIBLE_MODULE_ARGS': data}
+    testargs = ['module_file.py', json.dumps(cli_data)]
+    with mock.patch('ansible.module_utils.basic.AnsibleModule.warn') as mock_warn:
+        with mock.patch.object(sys, 'argv', testargs):
+            with mock.patch.object(TowerModule, 'load_config') as mock_load:
+                argument_spec = dict(
+                    name=dict(required=True),
+                    zig=dict(type='str'),
+                )
+                TowerModule(argument_spec=argument_spec)
+            mock_load.mock_calls[-1] == mock.call('my_config')
+    mock_warn.assert_called_once_with(
+        'The parameter(s) tower_username were provided at the same time as '
+        'tower_config_file. Precedence may be unstable, '
+        'we suggest either using config file or params.'
+    )