add an example

docs/sanic/testing.md

@@ -78,3 +78,50 @@ Just write tests like,
     assert doc.name == "Kobe Bryant"
     assert doc.team == "Lakers"
 ```
+
+[pytest-sanic](https://github.com/yunstanford/pytest-sanic) also provides some useful fixtures, like loop, unused_port,
+test_server, test_client.
+
+```python
+@pytest.yield_fixture
+def app():
+    app = Sanic("test_sanic_app")
+
+    @app.route("/test_get", methods=['GET'])
+    async def test_get(request):
+        return response.json({"GET": True})
+
+    @app.route("/test_post", methods=['POST'])
+    async def test_post(request):
+        return response.json({"POST": True})
+
+    yield app
+
+
+@pytest.fixture
+def test_cli(loop, app, test_client):
+    return loop.run_until_complete(test_client(app, protocol=WebSocketProtocol))
+
+
+#########
+# Tests #
+#########
+
+async def test_fixture_test_client_get(test_cli):
+    """
+    GET request
+    """
+    resp = await test_cli.get('/test_get')
+    assert resp.status == 200
+    resp_json = await resp.json()
+    assert resp_json == {"GET": True}
+
+async def test_fixture_test_client_post(test_cli):
+    """
+    POST request
+    """
+    resp = await test_cli.post('/test_post')
+    assert resp.status == 200
+    resp_json = await resp.json()
+    assert resp_json == {"POST": True}
+```