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Run .NET tests correctly using the test-with-timeout.sh wrapper to handle .NET 10 dual test runner modes and prevent test hangs.
Run .NET Tests
Purpose
Provide standardized instructions for running .NET 10 tests correctly. Ensures agents use the scripts/test-with-timeout.sh wrapper instead of direct dotnet test calls, which fail due to .NET 10's dual test runner architecture.
When to Use This Skill
Before committing code changes that affect C# code
When verifying bug fixes or new features
When running targeted tests during development
When the full test suite must pass before marking work complete
Hard Rules
Must
ALWAYS use scripts/test-with-timeout.sh wrapper - never call dotnet test directly
Run tests from the repository root (the wrapper handles directory changes automatically)
Use --solution src/tfplan2md.slnx for full test suite runs
Use --project with relative paths from src/ directory (e.g., --project tests/Oocx.TfPlan2Md.TUnit/)
Wait for test completion and check exit code (0 = pass, non-zero = fail)
For snapshot test changes, use the update-test-snapshots skill instead of manual edits
Must Not
NEVER run dotnet test directly from command line - it will fail with MSB1001: Unknown switch errors from repo root
Never manually edit snapshot files in src/tests/Oocx.TfPlan2Md.TUnit/TestData/Snapshots/ - use the update-test-snapshots skill
Never ignore test failures or skip tests to make CI pass
Never modify test expectations to match broken output - fix the code, not the tests
.NET 10 Dual Test Runner Issue
.NET 10 introduced two distinct test runners with incompatible CLI flags:
Working Directory
Runner Mode
--solution
--project
--treenode-filter
Result
Repo root (/)
VSTest
❌
❌
❌
MSBuild error MSB1001: Unknown switch
src/ (where global.json lives)
Microsoft.Testing.Platform
✅
✅
✅
Works correctly
The scripts/test-with-timeout.sh wrapper automatically:
Changes to the src/ directory (where global.json with "runner": "Microsoft.Testing.Platform" exists)
Normalizes any src/-prefixed paths in arguments
Enforces a timeout to prevent hung test runs (default 120 seconds)
Why direct dotnet test fails: Running from repo root activates VSTest mode (no global.json), which doesn't support --solution, --project, or --treenode-filter flags. The wrapper ensures tests run from src/ directory to activate Microsoft.Testing.Platform mode.
Common Test Commands
Run Full Test Suite
scripts/test-with-timeout.sh -- dotnet test --solution src/tfplan2md.slnx
Run Tests with Build
scripts/test-with-timeout.sh -- dotnet test --solution src/tfplan2md.slnx --configuration Release --verbosity normal
Run Tests Without Build (faster when already built)
scripts/test-with-timeout.sh -- dotnet test --solution src/tfplan2md.slnx --no-build
Override Timeout (for slow tests)
scripts/test-with-timeout.sh --timeout-seconds 300 -- dotnet test --solution src/tfplan2md.slnx
Run Specific Project Tests
scripts/test-with-timeout.sh -- dotnet test --project tests/Oocx.TfPlan2Md.TUnit/
TUnit Test Filtering
Important: This project uses TUnit (not xUnit). TUnit uses --treenode-filter instead of --filter. All TUnit-specific flags must come after -- in the wrapper command.
Filter by Class Name (hierarchical pattern)
scripts/test-with-timeout.sh -- dotnet test --project tests/Oocx.TfPlan2Md.TUnit/ --treenode-filter /*/*/MarkdownRendererTests/*
Filter by Test Method Name
scripts/test-with-timeout.sh -- dotnet test --project tests/Oocx.TfPlan2Md.TUnit/ --treenode-filter /*/*/*/Render_ValidPlan_ContainsSummarySection
Filter Pattern Explanation
TUnit uses hierarchical path patterns:
/*/*/*/TestMethodName - Match specific test method
/*/*/ClassName/* - Match all tests in a class
/*/Namespace.ClassName/* - Match by namespace and class
Workflow Integration
When to Run Tests
During Development (after each meaningful change):
# Run targeted tests for the area you modified
scripts/test-with-timeout.sh -- dotnet test --project tests/Oocx.TfPlan2Md.TUnit/ --treenode-filter /*/*/YourTestClass/*
Before Committing (C# code changes only):
# Run full test suite to ensure no regressions
scripts/test-with-timeout.sh -- dotnet test --solution src/tfplan2md.slnx --no-build
Skip Tests When (documentation/agent instructions only):
Changes are limited to .github/agents/, .github/skills/, .github/copilot-instructions.md, or docs/
No C# code was modified
The test suite doesn't validate these file types
Handling Test Failures
Read the failure output - TUnit provides detailed error messages
Identify the failing test - Look for the test method name and class
Run the specific failing test - Use --treenode-filter to isolate it
Debug and fix - Fix the code (never modify test expectations unless the test itself is wrong)
Re-run tests - Verify the fix works
Run full suite - Ensure no regressions before committing
Snapshot Test Changes
If tests fail because snapshot files need updating (intentional output changes):
Use the update-test-snapshots skill - Never manually edit snapshot files
Verify the new output is correct - Review the diff carefully
Include SNAPSHOT_UPDATE_OK in commit message - Document the intentional change
Re-run tests - Confirm all tests pass with new snapshots
Exit Codes
Exit Code
Meaning
Action
0
All tests passed
Proceed with commit
1-123
Test failures
Fix failing tests before committing
124
Timeout
Increase timeout with --timeout-seconds or investigate hung tests
125
Wrapper error
Check command syntax
Golden Example
Complete workflow for implementing a feature:
# 1. Build the project
dotnet build
# 2. Run targeted tests during development
scripts/test-with-timeout.sh -- dotnet test --project tests/Oocx.TfPlan2Md.TUnit/ --treenode-filter /*/*/MyFeatureTests/*
# 3. Make changes, run tests again
scripts/test-with-timeout.sh -- dotnet test --project tests/Oocx.TfPlan2Md.TUnit/ --treenode-filter /*/*/MyFeatureTests/*
# 4. Before committing, run full suite
scripts/test-with-timeout.sh -- dotnet test --solution src/tfplan2md.slnx --no-build
# 5. If all pass, commit changes
git add .
git commit -m "feat: implement my feature"
Troubleshooting
Error: MSBuild error MSB1001: Unknown switch
Cause: Running dotnet test directly from repo root (VSTest mode doesn't support --solution/--project flags)
Solution: Use scripts/test-with-timeout.sh wrapper
Error: Timeout after 120 seconds
Cause: Tests taking longer than default timeout
Solution: Increase timeout with --timeout-seconds 300 (or higher)
Error: Test not found with --treenode-filter
Cause: Incorrect filter pattern or test doesn't exist
Solution:
List all tests first: scripts/test-with-timeout.sh -- dotnet test --list-tests
