feat(test_stoplight_elements_docs.py): add tests for the new feature

tests/test_stoplight_elements_docs.py

@@ -0,0 +1,21 @@
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+app = FastAPI(title="White Shuli 2")
+
+@app.get("/pita/shuli")
+async def get_shuli_in_a_pita():
+    return {"shuli": "pita"}
+
+client = TestClient(app)
+
+def test_swagger_ui():
+    response = client.get("/elements")
+    assert response.status_code == 200, response.text
+    print(response.text)
+    assert app.title in response.text
+    assert "Stoplight" in response.text
+
+def test_response():
+    response = client.get("/pita/shuli")
+    assert response.json() == {"shuli": "pita"}