Merge create and update model to get read only properties (#715)

* Merge create and update model to get read only properties

Author: anshikg

src/rpdk/core/contract/resource_client.py

@@ -69,6 +69,24 @@ def prune_properties_if_not_exist_in_path(output_model, input_model, paths):
     return output_document["properties"]
 
 
+def prune_properties_which_dont_exist_in_path(model, paths):
+    """Prunes model to properties present in path. This method removes any property
+    from the model which does not exists in the paths
+
+    This assumes properties will always have an object (dict) as a parent.
+    The function returns the model after pruning all but the path which exists
+    in the paths tuple from the input_model
+    """
+    document = {"properties": model.copy()}
+    for model_path in model.keys():
+        path_tuple = ("properties", model_path)
+        if path_tuple not in paths:
+            _prop, resolved_path, parent = traverse(document, path_tuple)
+            key = resolved_path[-1]
+            del parent[key]
+    return document["properties"]
+
+
 def path_exists(document, path):
     try:
         _prop, _resolved_path, _parent = traverse(document, path)
@@ -426,7 +444,12 @@ def generate_update_example(self, create_model):
             if self.create_only_paths:
                 self.validate_update_example_keys(unique_identifiers, update_example)
             update_example.update(unique_identifiers)
-            return update_example
+            create_model_with_read_only_properties = (
+                prune_properties_which_dont_exist_in_path(
+                    create_model, self.read_only_paths
+                )
+            )
+            return {**create_model_with_read_only_properties, **update_example}
         overrides = self._overrides.get("UPDATE", self._overrides.get("CREATE", {}))
         example = override_properties(self.update_strategy.example(), overrides)
         return {**create_model, **example}

tests/contract/test_resource_client.py

@@ -15,6 +15,7 @@
     prune_properties,
     prune_properties_from_model,
     prune_properties_if_not_exist_in_path,
+    prune_properties_which_dont_exist_in_path,
 )
 from rpdk.core.exceptions import InvalidProjectError
 from rpdk.core.test import (
@@ -329,6 +330,21 @@ def test_prune_properties_if_not_exist_in_path():
     assert model == previous_model
 
 
+def test_prune_properties_which_dont_exist_in_path():
+    model = {
+        "spam": "eggs",
+        "one": "two",
+        "array": ["first", "second"],
+    }
+    model1 = prune_properties_which_dont_exist_in_path(
+        model,
+        [
+            ("properties", "one"),
+        ],
+    )
+    assert model1 == {"one": "two"}
+
+
 def test_init_sam_cli_client():
     patch_sesh = patch(
         "rpdk.core.contract.resource_client.create_sdk_session", autospec=True
@@ -1210,10 +1226,12 @@ def test_generate_invalid_update_example_with_inputs(resource_client_inputs):
 
 def test_generate_update_example_with_primary_identifier(resource_client_inputs_schema):
     created_resource = resource_client_inputs_schema.generate_create_example()
+    # adding read only property to denote a realistic scenario
+    created_resource["b"] = 2
     updated_resource = resource_client_inputs_schema.generate_update_example(
         created_resource
     )
-    assert updated_resource == {"a": 1, "c": 2}
+    assert updated_resource == {"a": 1, "c": 2, "b": 2}
 
 
 def test_generate_update_example_with_composite_key(