Tests: httpbin.org responding with 503 Service Temporarily Unavailable

[amotl]

Problem

The software test that uses https://httpbin.org/404 for receiving a 404 response on purpose fails.

 FAILED tests/test_prompt.py::test_fragment_remote_failure - AssertionError: Regex pattern did not match.
 Regex: "Failed to load fragment 'https://httpbin.org/404': Client error '404 NOT FOUND' for url 'https://httpbin.org/404'"
 Input: "Failed to load fragment 'https://httpbin.org/404': Server error '503 Service Temporarily Unavailable' for url 'https://httpbin.org/404'\nFor more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/503"

Thoughts

Maybe the software test can be relaxed by omitting comparing the error message?

[amotl]

Adjusted in GH-57 to also accept Server error messages.