Fix for contract test drift parity issue #1 (#589)

* fix to compare output model with input model
* encapsulating repeated error message in a variable

Author: prerna-p

src/rpdk/core/contract/resource_client.py

@@ -42,10 +42,10 @@ def prune_properties(document, paths):
 
 
 def prune_properties_if_not_exist_in_path(output_model, input_model, paths):
-    """Prune given properties from a document.
+    """Prune given properties from a model.
 
     This assumes properties will always have an object (dict) as a parent.
-    The function returns the document after pruning the path which exists
+    The function returns the model after pruning the path which exists
     in the paths tuple but not in the input_model
     """
     output_document = {"properties": output_model.copy()}

src/rpdk/core/contract/suite/handler_commons.py

@@ -154,8 +154,23 @@ def test_input_equals_output(resource_client, input_model, output_model):
     pruned_output_model = prune_properties_if_not_exist_in_path(
         output_model.copy(), pruned_input_model, resource_client.read_only_paths
     )
+
     pruned_output_model = prune_properties_if_not_exist_in_path(
         pruned_output_model, pruned_input_model, resource_client.create_only_paths
     )
 
-    assert pruned_input_model == pruned_output_model
+    assertion_error_message = (
+        "All properties specified in the request MUST "
+        "be present in the model returned, and they MUST"
+        " match exactly, with the exception of properties"
+        " defined as writeOnlyProperties in the resource schema"
+    )
+    # only comparing properties in input model to those in output model and
+    # ignoring extraneous properties that maybe present in output model.
+    try:
+        assert all(
+            pruned_input_model[key] == pruned_output_model[key]
+            for key in pruned_input_model
+        ), assertion_error_message
+    except KeyError as e:
+        raise AssertionError(assertion_error_message) from e