Replace external Wikipedia dependency in tests with local servers

[delphaber]

Summary

• The HTTPS and large-image tests relied on a live Wikipedia URL, causing flaky failures due to HTTP 429 rate limiting
• Replaced with two local test servers:
  • SlowServer (raw TCP): sends JPEG header immediately then drip-feeds padding bytes with 0.5s delays, verifying FastImage reads only the minimum bytes needed rather than downloading the entire body
  • HTTPSServer (WEBrick + self-signed cert): exercises the real SSL codepath (use_ssl, verify_mode, etc.) without depending on external services
• Added webrick as a dev dependency (needed for the HTTPS server)
• Removed redundant constants (LargeImage, LargeImageInfo, LargeImageFetchLimit, HTTPSImage, HTTPSImageInfo) in favor of referencing GoodFixtures directly

Test plan

• All 60 tests pass locally
• No external network dependencies remain in the test suite (except test_should_raise_when_asked_to_when_file_does_not_exist and test_should_work_with_domains_with_underscores)
• HTTPS test exercises real SSL handshake with self-signed certificate
• Large image test confirms FastImage returns in <2s despite server needing 50+ seconds to send full body

🤖 Generated with Claude Code

[delphaber]

I tried to remove the dependency on external URLs because wikipedia is rate limiting us.

With the help of Claude I created two fake web servers:

• one web server that supports https (to test that FastImage is able to manage HTTPS urls)
• one web server that after the initial headers it will stream padding in a slow way, so that we can test that FastImage only downloads the headers

It's a lot of code, I know, and these are more like "integration" test than unit tests.

What do you think? :)

[delphaber]

There are 3 pending tests that are still in the queue. I think they are stuck, but I don't know why

[sdsykes]

I think this could be a good approach. Odd that those tests are stuck though, but I could also maybe drop official support for 2.2 and below (over 12 years old now). I'll see if I can re-run the tests anyway.

[sdsykes]

I've dropped the old versions, they relied on ubuntu 20 which is not available in github actions any more. It should hopefully work ok if you rebase.

[delphaber]

Rebased and now all tests are passing :), even ruby 4.0