verify-tests-fail-without-fix - SKILL.md Agent Skill

name: verify-tests-fail-without-fix description: Verifies tests catch the bug. Auto-detects test type (UI tests, device tests, unit tests) and dispatches to the appropriate runner. Supports two modes - verify failure only (test creation) or full verification (test + fix validation). metadata: author: dotnet-maui version: "2.0" compatibility: Requires git, PowerShell, and .NET SDK for building and running tests.

Verify Tests Fail Without Fix

Verifies tests actually catch the issue. Supports all test types (UI tests, unit tests, XAML tests, device tests) and two workflow modes.

Supported Test Types

Test Type	Auto-Detected From	Runner
UITest	`TestCases.Shared.Tests/`, `TestCases.HostApp/`	`BuildAndRunHostApp.ps1`
DeviceTest	`DeviceTests/`	`Run-DeviceTests.ps1`
UnitTest	`*.UnitTests/`, `Graphics.Tests/`	`dotnet test`
XamlUnitTest	`Xaml.UnitTests/`	`dotnet test`

Test type is auto-detected from changed files. Override with -TestType if needed.

-Platform is required for UI and Device tests. It selects which platform to verify the fix on. Unit and XAML tests do not require -Platform.

Activation Guard

🛑 This skill ONLY verifies that existing tests reproduce a bug. Do NOT activate for:

Writing new tests → use write-tests-agent
Running tests without verification context → use run-device-tests
Code review → use code-review skill
General test advice

Requires: a platform and either test files in the PR or an explicit TestFilter.

⚠️ CRITICAL: Inverted Pass/Fail Semantics

In this skill, test outcomes mean the OPPOSITE of normal:

Test Result (without fix)	Verification Result	Why
Tests FAIL	✅ GOOD	Tests detect the bug
Tests PASS	❌ BAD	Tests miss the bug

NEVER say "verification passed" when tests PASS without the fix.

Workflow

Step 1: Determine Mode

Check if fix files exist in the PR (non-test code changes detected by the script from the git diff)
If fix files present → Full Verification mode (-RequireFullVerification)
If no fix files → Verify Failure Only mode (omit the flag)

Step 2: Construct Command

pwsh .github/skills/verify-tests-fail-without-fix/scripts/verify-tests-fail.ps1 `
  -Platform <platform> `
  -TestFilter "<filter>" `
  [-RequireFullVerification]  # Only if fix files exist

Step 3: Interpret Results

⚠️ Remember: test outcomes are INVERTED from normal!

Script outputs VERIFICATION PASSED → Tests catch the bug ✅
Script outputs VERIFICATION FAILED → Tests don't catch the bug ❌
Script outputs error/timeout → Report as Blocked

Step 4: Report

Report the result to the invoking orchestrator

Mode 1: Verify Failure Only (Test Creation)

Use when creating tests before writing a fix:

Runs tests to verify they FAIL (proving they catch the bug)
No fix files required
Perfect for test-first development

# Auto-detect test type and filter
pwsh .github/skills/verify-tests-fail-without-fix/scripts/verify-tests-fail.ps1 -Platform android

# Explicit test type + filter
pwsh .github/skills/verify-tests-fail-without-fix/scripts/verify-tests-fail.ps1 -Platform android -TestType UnitTest -TestFilter "Maui12345"

Mode 2: Full Verification (Fix Validation)

Use when validating both tests and fix:

Without fix - tests should FAIL (bug is present)
With fix - tests should PASS (bug is fixed)

# Auto-detect everything (recommended)
pwsh .github/skills/verify-tests-fail-without-fix/scripts/verify-tests-fail.ps1 -Platform android -RequireFullVerification

# With explicit test filter
pwsh .github/skills/verify-tests-fail-without-fix/scripts/verify-tests-fail.ps1 -Platform ios -TestFilter "Issue33356" -RequireFullVerification

Note: -RequireFullVerification ensures the script errors if no fix files are detected, preventing silent fallback to failure-only mode.

Requirements

Verify Failure Only Mode:

Test files in the PR (or working directory)

Full Verification Mode:

Test files in the PR
Fix files in the PR (non-test code changes)

The script auto-detects which mode to use based on whether fix files are present.

Expected Output

Verify Failure Only Mode:

╔═══════════════════════════════════════════════════════════╗
║              VERIFICATION PASSED ✅                       ║
╠═══════════════════════════════════════════════════════════╣
║  Tests FAILED as expected!                                ║
║  This proves the tests correctly reproduce the bug.       ║
╚═══════════════════════════════════════════════════════════╝

Full Verification Mode:

╔═══════════════════════════════════════════════════════════╗
║              VERIFICATION PASSED ✅                       ║
╠═══════════════════════════════════════════════════════════╣
║  - FAIL without fix (as expected)                         ║
║  - PASS with fix (as expected)                            ║
╚═══════════════════════════════════════════════════════════╝

What It Does

Verify Failure Only Mode (no fix files):

Fetches base branch from origin (if available)
Auto-detects test type from changed files (UITest, UnitTest, XamlUnitTest, DeviceTest)
Auto-detects test classes from changed test files
Routes to the appropriate test runner
Runs tests (should FAIL to prove they catch the bug)
Reports result

Full Verification Mode (fix files detected):

Fetches base branch from origin to ensure accurate diff
Auto-detects fix files (non-test code) from git diff
Auto-detects test type and test classes from changed files
Reverts fix files to base branch
Runs tests using the appropriate runner (should FAIL without fix)
Restores fix files
Runs tests using the appropriate runner (should PASS with fix)
Generates markdown reports:
- CustomAgentLogsTmp/TestValidation/verification-report.md - Full detailed report
- CustomAgentLogsTmp/PRState/verification-report.md - Validate section for agent
Reports result

Note: PR label management (s/ai-reproduction-confirmed / s/ai-reproduction-failed) is handled by Review-PR.ps1, not by this script.

Output Files

The skill generates output files under CustomAgentLogsTmp/PRState/<PRNumber>/PRAgent/gate/verify-tests-fail/:

File	Description
`verification-report.md`	Comprehensive markdown report with test results and full logs
`verification-log.txt`	Text log of the verification process
`test-without-fix.log`	Full test output from run without fix
`test-with-fix.log`	Full test output from run with fix

Plus test logs in CustomAgentLogsTmp/:

UITests/ - UI test device logs and output
DeviceTests/ - Device test output
UnitTests/ - Unit test output

Example structure:

CustomAgentLogsTmp/
├── UITests/                           # UI test logs
│   ├── android-device.log
│   └── test-output.log
├── DeviceTests/                       # Device test logs
│   └── test-output.log
├── UnitTests/                         # Unit/XAML test logs
│   └── test-output.log
└── PRState/
    └── 27847/
        └── PRAgent/
            └── gate/
                └── verify-tests-fail/
            ├── verification-report.md  # Full detailed report
            ├── verification-log.txt
            ├── test-without-fix.log
            └── test-with-fix.log

PR Number Detection:

Auto-detected from branch name (e.g., pr-27847)
Falls back to gh pr view command
Uses "unknown" if detection fails
Can be manually specified with -PRNumber parameter

Troubleshooting

Problem	Cause	Solution
No fix files detected	Base branch detection failed or no non-test files changed	Use `-FixFiles` or `-BaseBranch` explicitly
Tests pass without fix	Tests don't detect the bug	Review test assertions, update test
Tests fail with fix	Fix doesn't work or test is wrong	Review fix implementation
App crashes	Duplicate issue numbers, XAML error	Check device logs
Element not found	Wrong AutomationId, app crashed	Verify IDs match

Optional Parameters

# Require full verification (fail if no fix files detected) - recommended
-RequireFullVerification

# Explicit test type (auto-detected if omitted)
-TestType UnitTest    # or XamlUnitTest, DeviceTest, UITest

# Explicit test filter
-TestFilter "Issue32030|ButtonUITests"

# Explicit fix files  
-FixFiles @("src/Core/src/File.cs")

# Explicit base branch
-BaseBranch "main"