A steam locomotive from 1993 broke my yarn test
2 days ago
- #React
- #Jest
- #Troubleshooting
- Pair programming session to start with React for an internal Backstage instance.
- First React commit led to a yarn test failure with a cryptic [Error].
- Multiple troubleshooting attempts failed to resolve the issue.
- Discovered Jest was hanging due to a timeout after exactly 27 seconds.
- Identified the issue was related to Jest mistakenly running the 'sl' (Steam Locomotive) command instead of the intended 'sl' (Sapling CLI).
- The 'sl' command's execution time caused Jest to crash consistently after 27 seconds.
- The problem was resolved by renaming the 'sl' command to avoid the naming clash.
- Investigation revealed Jest was running 'sl' in waves, with each wave taking about 6.7 seconds, totaling close to 27 seconds before crashing.
- The error was due to Jest interpreting the output of the 'sl' command as a repository path, leading to a failure.