Apply suggestions from code review

Author: chipytux

tests/assets/with_docs_url_set.py

@@ -8,4 +8,4 @@
 
 @app.get("/")
 def api_root():
-    return {"message": "single file api"}
+    return {"message": "any message"}

tests/assets/without_docs_url_set.py

@@ -8,4 +8,4 @@
 
 @app.get("/")
 def api_root():
-    return {"message": "single file api"}
+    return {"message": "any message"}