test-output-to-logfile

name	test-output-to-logfile
description	When running test scripts or long-running commands that produce verbose output, redirect output to a log file under logs/ to avoid truncation in the Bash tool. Claude should use this skill when running test scripts, end-to-end tests, or any command likely to produce large output. NOTE: This skill does not apply to Gradle because test output is written to TEST*.xml files.

Redirect verbose command output to log files

When running test scripts or any command that may produce large output (e.g. end-to-end tests, integration tests, build scripts):

Setup

1. Ensure a logs/ directory exists in the project root
2. Ensure log files are covered by .gitignore (either logs/ or *.log)

Running the command

3. Redirect both stdout and stderr to a file under logs/, and run in the background:

   ./build-and-test-all.sh > logs/build-and-test.log 2>&1
   

   Use run_in_background: true on the Bash tool so you can monitor progress immediately rather than waiting for completion.

4. Keep commands simple. Avoid compound commands with &&, quoted flag characters, or other complexity that may be rejected by the Bash tool permission system. Run each command as a separate Bash call.

Monitoring

5. Actively monitor the log file while the command runs — don't just wait for completion:

   tail -30 logs/build-and-test.log
   

6. When Docker containers are involved, check their health in parallel:

   docker ps --format "table {{.Names}}\t{{.Status}}"
   

7. Diagnose issues as soon as they appear in the log. Don't wait for the command to finish if you can see it's already failing.

After completion

8. Check the exit code from the background task notification
9. If the command failed, use tail or Grep on the log file to find the error:

   Grep with pattern="FAILED|error|Exception" path="logs/build-and-test.log" output_mode="content"
   

10. For Gradle/JUnit failures, read the TEST-*.xml files rather than parsing log output — they contain full stack traces

This prevents the Bash tool from truncating output and losing important error details.