Disallow posting dictionary as credentials to JT launch API endpoint.

awx/main/tests/unit/api/serializers/test_primary_key_related_field.py

@@ -0,0 +1,16 @@
+# Python
+import pytest
+
+# Django Rest Framework
+from rest_framework.exceptions import ValidationError
+
+# AWX
+from awx.api.serializers import JobLaunchSerializer
+
+
+def test_primary_key_related_field():
+    # We are testing if the PrimaryKeyRelatedField in this serializer can take dictionary.
+    # PrimaryKeyRelatedField should not be able to take dictionary as input, and should raise a ValidationError.
+    data = {'credentials' : {'1': '2', '3':'4'}}
+    with pytest.raises(ValidationError):
+        JobLaunchSerializer(data=data)