Replace httpbin service with pytest-httpserver

import pytest

import requests

import responses

from werkzeug.wrappers.response import Response

from galaxy.util import url_get

def test_get_url_retry_after(httpserver):

    # This test is not ideal since it contacts an external resource

    # and doesn't actually verify multiple attempts have been made.

    # responses doesn't mock the right place to fully simulate this.

    httpserver.expect_request("/429").respond_with_data("try again later", status=429, content_type="text/plain")

    attempts = []

    def retry_handler(request):

        attempts.append(requests)

        if len(attempts) < 4:

            return Response("try again later", status=429, content_type="text/plain")

        else:

            return Response("ok", status=200, content_type="text/plain")

    httpserver.expect_request("/429").respond_with_handler(retry_handler)

    url = httpserver.url_for("/429")

    with pytest.raises(requests.exceptions.RetryError):

        url_get(url, max_retries=2, backoff_factor=0.01)

        url_get(url, max_retries=1, backoff_factor=0.01)

    assert len(attempts) == 2

    response = url_get(url, max_retries=2, backoff_factor=0.01)

    assert len(attempts) == 4

    assert response == "ok"