How can i use a subdomain for my tests

[jonthdiaz]

Hello...

I want to use some like

    response = yield http_client.fetch(
        "http://pytest.localhost:port/login/",
        method="POST",
        headers=basic_headers,
        body="",
        raise_error=False,
    )

but when run the test I got: [Errno -2] Name or service not known