Wallaby Testing

Wallaby Testing Skill

Check test status and debug failing tests using Wallaby.js real-time test execution data.

When to Use

• After code changes - Verify tests pass after modifications
• Checking test status - See if any tests are failing
• Debugging failures - Analyze test errors and exceptions
• Inspecting runtime values - Examine variable states during tests
• Understanding coverage - See which code paths tests execute
• Updating snapshots - When snapshot changes are needed
• User mentions "tests", "test status", "run tests", or "Wallaby"

Available Wallaby Tools

Use these tools to gather test information:

What Inputs These Tools Need

• For file-scoped tools (like wallaby_failingTestsForFile, wallaby_coveredLinesForFile): pass the workspace-relative file path.
• For line-scoped tools (like wallaby_allTestsForFileAndLine, wallaby_runtimeValues): pass file, line, and the exact lineContent string from the file.
• For test-scoped tools (like wallaby_testById, wallaby_runtimeValuesByTest, wallaby_coveredLinesForTest): pass testId from wallaby_failingTests / wallaby_allTests.

Debugging Workflow

Step 1: Get Failing Tests

Start by retrieving failing test information:

• Use wallaby_failingTests to see all failures
• Review error messages and stack traces
• Note the test ID for further inspection

If there are no failing tests but the user is asking about test status or coverage, use wallaby_allTests to confirm the current state and to obtain test IDs.

Step 2: Locate Related Code (Optional)

If the error and stack trace from Step 1 don't provide enough context:

• Use wallaby_coveredLinesForTest with the test ID
• Focus analysis on covered source files
• Identify which code paths are executed
• Skip this step if the failure cause is already clear

Step 3: Inspect Runtime Values (Optional)

Examine variable states at failure points or other points of interest:

• Use wallaby_runtimeValues for specific locations
• Use wallaby_runtimeValuesByTest for test-specific values
• Compare expected vs actual values
• Skip this step if the failure cause is already clear

Step 4: Implement Fix

Based on analysis:

• Identify the root cause
• Make targeted code changes
• Reference runtime values in your explanation

Step 5: Verify Fix

After changes:

• Wallaby re-runs tests automatically
• Use wallaby_testById to confirm test passes
• Check no regressions with wallaby_failingTests

Step 6: Update Snapshots (if needed)

When snapshots need updating:

• Use wallaby_updateTestSnapshots for specific tests
• Use wallaby_updateFileSnapshots for all in a file
• Use wallaby_updateProjectSnapshots only when many snapshots changed
• Verify tests pass after updates

Example: Debugging an Assertion Failure

1. Call wallaby_failingTests → Get test ID and error Error shows: "expected 4, got 5" in multiply function
2. (Optional) Call wallaby_coveredLinesForTest(testId) → Skip if error is clear
3. (Optional) Call wallaby_runtimeValues(file, line, expression) → Skip if cause is obvious
4. Analyze: multiply used + instead of *
5. Fix: Change + to * in calculator.js
6. Call wallaby_failingTests → Confirm no failures remain

Best Practices

• Use Wallaby tools first - They provide real-time data without re-running tests
• Get test IDs early - Many tools require the test ID from initial queries
• Inspect runtime values - More reliable than guessing variable states
• Verify after fixes - Always confirm the test passes before finishing
• Check for regressions - Ensure fixes don't break other tests