update tests for Flask

tests/test_basic.py

@@ -1,7 +1,3 @@
-import pytest
-
-
-@pytest.mark.gen_test
-def test_hello_world(http_client, base_url):
-    response = yield http_client.fetch(base_url)
-    assert response.code == 200
+def test_hello_world(client):
+    response = client.get("/")
+    assert response.status_code == 200