from io import StringIO import flask def test_suppressed_exception_logging(): class SuppressedFlask(flask.Flask): def log_exception(self, exc_info): pass out = StringIO() app = SuppressedFlask(__name__) @app.route("/") def index(): raise Exception("test") rv = app.test_client().get("/", errors_stream=out) assert rv.status_code == 500 assert b"Internal Server Error" in rv.data assert not out.getvalue()