Keep use f""" for expected

Author: jyscao

pandas/tests/io/json/test_pandas.py

@@ -1457,18 +1457,16 @@ def test_to_json_indent(self, indent):
 
         result = df.to_json(indent=indent)
         spaces = " " * indent
-        expected = (
-            '{\n'
-            f'{spaces}"a":{{\n'
-            f'{spaces}{spaces}"0":"foo",\n'
-            f'{spaces}{spaces}"1":"baz"\n'
-            f'{spaces}}},\n'
-            f'{spaces}"b":{{\n'
-            f'{spaces}{spaces}"0":"bar",\n'
-            f'{spaces}{spaces}"1":"qux"\n'
-            f'{spaces}}}\n'
-            '}'
-        )
+        expected = f"""{{
+{spaces}"a":{{
+{spaces}{spaces}"0":"foo",
+{spaces}{spaces}"1":"baz"
+{spaces}}},
+{spaces}"b":{{
+{spaces}{spaces}"0":"bar",
+{spaces}{spaces}"1":"qux"
+{spaces}}}
+}}"""
 
         assert result == expected