Эмулятор внешних API для тестирования

Last week I asked here how people test against third-party APIs they don't control. Most answers came down to the same thing: fixtures rot, and if you're disciplined you run something against the real API at night. I've been working on a small server for that problem and wanted to show it. It's a local server that answers the way Slack, Gmail, Google Drive, GitHub, Jira, Notion and S3 do. You point the vendor's own SDK at localhost and it gets the same response shapes, cursors, auth errors and per-user permissions the real service sends, out of one SQLite file you control. No account with the vendor, no OAuth app, no token in CI, no network. Why not a mock: a mock I write returns what I already think the API returns, so it can't disagree with me. This was built by measuring the real resp…