diagnosing-vcr-failures

Diagnose and Fix go-vcr Test Failures

This skill covers diagnosing failures in ASO's go-vcr recording/replay tests (both controller CRUD and sample tests) and re-recording when needed.

For running tests and understanding the test suites, see the testing-aso-recordings skill.

Quick Reference

Identifying Failures

Logs overflow the terminal buffer. Always use the log file (see table above).

• Search for FAIL: (trailing colon avoids false positives).
• Initial failures often cascade — identify the first problem.
• Compare the error message against the known failure modes below.

Known Failure Modes

IMPORTANT: Before deleting a recording and re-recording, always investigate WHY the test failed. Blindly re-recording wastes time (30–60 min) and may not fix the problem. If you can't determine the root cause, report to the user and ask for guidance.

Missing interaction

Signature: go-vcr error containing "no responses recorded for this method/URL".

The test made an HTTP request that doesn't exist in the recording.

• If recording is unmodified (git status shows clean) → the recording is stale. Delete it and re-record.
• If recording was already updated (you just re-recorded or it shows modified in git) → the test or controller is making an unexpected request. Investigate what changed; report to user.

Body hash mismatch

Signature: go-vcr error containing "body mismatch" and/or logs showing "Request body hash header mismatch".

The test found the right URL in the recording but the request body differs.

• Recording unmodified → stale, re-record.
• Recording just created (you literally just recorded it) → non-deterministic serialization. The request body is being serialized differently across runs. This is a systemic issue. Do NOT keep re-recording — report to user.

Test assertion failure

Signature: assertion error from test code (e.g. "Expected true to be false", "Expected ... to have length"), NOT a go-vcr error.

• During recording (live Azure) → likely a real bug in the controller or test code. Report to user.
• During playback → typically means the replay roundtripper is returning stale cached responses that don't reflect the current resource state. The recording may need re-creating, but if not, report the specific assertion and context to user.

Timeout while recording

Signature: test fails with a context deadline or timeout during a live Azure recording run.

Some resources take 30+ min to provision (ApiManagement, Kusto, etc.) and the default test timeout may be insufficient.

• Extend timeout: add TIMEOUT=90m to the command line.
• If the test still fails with a longer timeout, investigate further (e.g., is the resource stuck provisioning?) and report to user.

Lack of capacity or quota

Signature: ServiceUnavailable with a message about "high demand" in a region, or quota/capacity exceeded errors during recording.

1. Check the sample YAML for location/locationName fields.
2. Check what regions other samples in the same resource group use — prefer consistency.
3. Update the sample YAML to use a different Azure region (e.g. eastus → australiaeast or westus2).
4. Delete the failed/partial recording and re-run.
5. If the new region also fails, try another region and repeat.

Re-Recording Workflow

Step 1: Delete the stale recording

Delete the recording file for the failing test from the appropriate recordings directory (see Quick Reference table).

Step 2: Record

Run as a background terminal:

Controllers:

source test.env && TIMEOUT=60m TEST_FILTER="<your-test-here>" task controller:test-controllers

Samples (note the Test_Samples_CreationAndDeletion/ prefix is required):

source test.env && TIMEOUT=60m TEST_FILTER="Test_Samples_CreationAndDeletion/<your-test-here>" task controller:test-samples

Example: to re-record Test_Redis_v1api20230801_CreationAndDeletion:

source test.env && TIMEOUT=60m TEST_FILTER="Test_Samples_CreationAndDeletion/Test_Redis_v1api20230801_CreationAndDeletion" task controller:test-samples

For slow-provisioning resources, use TIMEOUT=90m. Record one test at a time to isolate problems.

Step 3: Verify playback

Run the same command without source test.env:

TIMEOUT=60m TEST_FILTER="<your-test-here>" task controller:<SUITE>

Playback takes 1–3 min. If playback fails but recording succeeded, this is a systemic VCR issue (e.g. non-deterministic request serialization) — do NOT keep re-recording. Investigate and report.

Step 4: Handle failed recording attempts

When a recording attempt fails, watch for:

1. Azure debris — failed runs can leave resources in Azure (resource groups, Entra security groups, etc.) that weren't cleaned up. On retry, the test may adopt these pre-existing resources instead of creating new ones, causing unexpected behavior. Wait a few minutes for Azure cleanup, delete the partial recording, and try again. Sometimes the quickest fix is to run a live test (which will delete everything in the resource group) and then re-record.

Step 5: Run the full suite

Once updated recordings pass individually, re-run the full test suite to confirm all tests pass. A test run exits on first failure, leaving later tests unexecuted. The full re-run confirms all problems are resolved and there are no hidden issues.

If new failures appear, loop back to the top and diagnose them.

Guidance

• DO NOT interrupt a test run, even if slow. Interrupting can leave Azure debris that pollutes the next recording attempt.
• NEVER modify recording files by hand. They are machine-generated and must only be created by running the tests.
• DO NOT analyze recording YAML files to debug mismatches. They're large and machine-generated — manual inspection is not productive. Delete and re-record instead.
• ALWAYS use task directly — never use ./hack/tools/task. If task is not on the PATH, your environment is not set up correctly for testing. Stop and ask the user to fix your environment.
• Monitoring: Run as background terminals and use await_terminal. DO NOT poll logs in a loop. Timeouts:
  • Playback (single): 5 min (300000ms)
  • Recording (single): 10 min (600000ms), then repeat — can take 20–60+ min
  • If await_terminal times out, just call it again.

Postrequisites

When finished, provide a table to the user showing which tests were re-recorded and why.