don't rewrite string quotes inside f-strings
diff --git a/tests/string_fixer_test.py b/tests/string_fixer_test.py
index 9dd7315..8eb164c 100644
--- a/tests/string_fixer_test.py
+++ b/tests/string_fixer_test.py
@@ -37,6 +37,12 @@
         1,
     ),
     ('"foo""bar"', "'foo''bar'", 1),
+    pytest.param(
+        "f'hello{\"world\"}'",
+        "f'hello{\"world\"}'",
+        0,
+        id='ignore nested fstrings',
+    ),
 )