Fix test_actual_config_files: read expectations from default.yml

[jonnyspicer]

Part of 86cb4jfk7. This repo's suite has never run in CI; running it gives 18 passed, 1 failed.

Root cause

test_actual_config_files runs the merger against the real config/ directory, then asserted hardcoded San Francisco coordinates:

# Check expected values from default.yml (San Francisco location)
self.assertIn('RECEIVER_LAT=37.7644', env_content)

64ff0c9 (2026-03-23, "Replace site-specific defaults with generic placeholders") deliberately changed those to Greenwich. The config change was correct; the test duplicated data it did not own and was never updated. It has failed for five months without anyone knowing.

The fix

The test's purpose, per its own docstring, is "merge with actual config files from retina-node repo" — that the merger propagates the real config into tar1090.env. The particular coordinates are incidental, so it now reads them from default.yml.

Its sibling test_tar1090_env_uses_location_rx keeps its literal 37.7644 — that test writes its own default.yml, so those are its fixture data rather than a claim about the repo's config. That difference is exactly why one broke and one did not.

Verification, both directions

Updating the numbers would have made the test pass while leaving it just as brittle, so the fix was checked against both failure modes:

• Changed default.yml's location to arbitrary values → test still passes (it no longer duplicates config data)
• Broke the merger so it stops propagating latitude → test still fails (it still tests what it claims to)

Suite: 19 passed, 0 failed.

🤖 Generated with Claude Code

https://claude.ai/code/session_013ZcazeseXVpu8XrYA2tE1V