add test to check parameter uniqueness is handled correctly in validator

tests/integration/test_validators.py

@@ -306,8 +306,7 @@ class TestPathItemParamsValidator(object):
         assert result.parameters == {'query': {'resId': 10}}
 
     def test_request_override_param(self, spec_dict):
-        # override parameter path parameter on operation
+        # override path parameter on operation
-        # (name and in property must match)
         spec_dict["paths"]["/resource"]["get"]["parameters"] = [
             {
                 # full valid parameter object required
@@ -327,6 +326,29 @@ class TestPathItemParamsValidator(object):
         assert result.body is None
         assert result.parameters == {}
 
+    def test_request_override_param_uniqueness(self, spec_dict):
+        # add parameter on operation with same name as on path but
+        # different location
+        spec_dict["paths"]["/resource"]["get"]["parameters"] = [
+            {
+                # full valid parameter object required
+                "name": "resId",
+                "in": "header",
+                "required": False,
+                "schema": {
+                    "type": "integer",
+                },
+            }
+        ]
+        validator = RequestValidator(create_spec(spec_dict))
+        request = MockRequest('http://example.com', 'get', '/resource')
+        result = validator.validate(request)
+
+        assert len(result.errors) == 1
+        assert type(result.errors[0]) == MissingRequiredParameter
+        assert result.body is None
+        assert result.parameters == {}
+
 
 class TestResponseValidator(object):