Execution result formatting: More tests and cosmetics

Author: Cito

src/graphql/execution/execute.py

@@ -131,12 +131,12 @@ def __iter__(self) -> Iterable[Any]:
     @property
     def formatted(self) -> Dict[str, Any]:
         """Get execution result formatted according to the specification."""
-        formatted_errors = ([err.formatted for err in self.errors]
-                            if self.errors is not None
-                            else None)
+        errors = (
+            None if self.errors is None else [error.formatted for error in self.errors]
+        )
         if self.extensions is None:
-            return dict(data=self.data, errors=formatted_errors)
-        return dict(data=self.data, errors=formatted_errors, extensions=self.extensions)
+            return dict(data=self.data, errors=errors)
+        return dict(data=self.data, errors=errors, extensions=self.extensions)
 
     def __eq__(self, other: Any) -> bool:
         if isinstance(other, dict):

tests/execution/test_execution_result.py

@@ -33,12 +33,26 @@ def prints_a_representation():
         )
 
     def formats_properly():
+        res = ExecutionResult(data, None)
+        assert res.formatted == {
+            "data": data,
+            "errors": None,
+        }
         res = ExecutionResult(data, errors)
-        assert res.formatted == {"data": data, "errors": [{'message': 'Some error', 'locations': None, 'path': None}]}
+        assert res.formatted == {
+            "data": data,
+            "errors": [{"message": "Some error", "locations": None, "path": None}],
+        }
+        res = ExecutionResult(data, None, extensions)
+        assert res.formatted == {
+            "data": data,
+            "errors": None,
+            "extensions": extensions,
+        }
         res = ExecutionResult(data, errors, extensions)
         assert res.formatted == {
             "data": data,
-            "errors": [{'message': 'Some error', 'locations': None, 'path': None}],
+            "errors": [{"message": "Some error", "locations": None, "path": None}],
             "extensions": extensions,
         }