sanic/tests/test_bad_request.py

import asyncio


def test_bad_request_response(app):
    lines = []

    @app.listener("after_server_start")
    async def _request(sanic, loop):
        connect = asyncio.open_connection("127.0.0.1", 42101)
        reader, writer = await connect
        writer.write(b"not http\r\n\r\n")
        while True:
            line = await reader.readline()
            if not line:
                break
            lines.append(line)
        app.stop()

    app.run(host="127.0.0.1", port=42101, debug=False)
    assert lines[0] == b"HTTP/1.1 400 Bad Request\r\n"
    assert b"Bad Request" in lines[-1]