.NET Test Execution

Basic Test Commands

# Run all tests in solution
dotnet test

# Run tests in specific project
dotnet test tests/MyApp.Tests/MyApp.Tests.csproj

# Run without build (faster if already built)
dotnet test --no-build

# Run without restore
dotnet test --no-restore

Test Filtering

By Name

# Filter by fully qualified name (contains)
dotnet test --filter "FullyQualifiedName~OrderService"

# Filter by test name (exact match)
dotnet test --filter "Name=CreateOrder_ValidInput_ReturnsOrder"

# Filter by display name
dotnet test --filter "DisplayName~Create Order"

By Category/Trait

# Filter by trait (xUnit)
dotnet test --filter "Category=Unit"
dotnet test --filter "Category!=Integration"

# Multiple trait filters
dotnet test --filter "Category=Unit&Priority=High"
dotnet test --filter "Category=Unit|Category=Integration"

By Class/Namespace

# Filter by class name
dotnet test --filter "ClassName=OrderServiceTests"

# Filter by namespace
dotnet test --filter "FullyQualifiedName~MyApp.Tests.Services"

Complex Filters

# Combine with operators
# & (and), | (or), ! (not), ~ (contains), = (equals)

# Unit tests except slow ones
dotnet test --filter "Category=Unit&Category!=Slow"

# All tests in namespace containing "Order"
dotnet test --filter "FullyQualifiedName~Order&Category!=Integration"

Test Output

Verbosity Levels

# Quiet (minimal output)
dotnet test --verbosity quiet
dotnet test -v q

# Normal (default)
dotnet test --verbosity normal

# Detailed (shows all test names)
dotnet test --verbosity detailed
dotnet test -v d

# Diagnostic (maximum output)
dotnet test --verbosity diagnostic

Logger Options

# Console logger with verbosity
dotnet test --logger "console;verbosity=detailed"

# TRX (Visual Studio Test Results)
dotnet test --logger trx

# JUnit format (for CI systems)
dotnet test --logger "junit;LogFileName=results.xml"

# HTML report
dotnet test --logger "html;LogFileName=results.html"

# Multiple loggers
dotnet test --logger trx --logger "console;verbosity=detailed"

Results Directory

# Specify results output directory
dotnet test --results-directory ./TestResults

Code Coverage

Collect Coverage

# Basic coverage collection
dotnet test --collect:"XPlat Code Coverage"

# With Coverlet
dotnet test /p:CollectCoverage=true

# Coverlet with specific format
dotnet test /p:CollectCoverage=true /p:CoverletOutputFormat=cobertura

# Multiple formats
dotnet test /p:CollectCoverage=true /p:CoverletOutputFormat=\"opencover,cobertura\"

Coverage Thresholds

# Fail if coverage below threshold
dotnet test /p:CollectCoverage=true /p:Threshold=80

# Per-type thresholds
dotnet test /p:CollectCoverage=true /p:ThresholdType=line /p:Threshold=80

Coverage Reports

# Install report generator
dotnet tool install -g dotnet-reportgenerator-globaltool

# Generate HTML report
reportgenerator -reports:coverage.cobertura.xml -targetdir:coveragereport

Parallel Execution

# Control parallelism
dotnet test --parallel

# Limit parallel workers
dotnet test -- RunConfiguration.MaxCpuCount=4

# Disable parallel execution
dotnet test -- RunConfiguration.DisableParallelization=true

Test Timeouts

# Set test timeout (milliseconds)
dotnet test -- RunConfiguration.TestSessionTimeout=60000

// Per-test timeout (xUnit)
[Fact(Timeout = 5000)]
public void SlowTest() { }

// Per-test timeout (NUnit)
[Test, Timeout(5000)]
public void SlowTest() { }

Configuration Files

runsettings

<!-- test.runsettings -->
<?xml version="1.0" encoding="utf-8"?>
<RunSettings>
  <RunConfiguration>
    <MaxCpuCount>4</MaxCpuCount>
    <ResultsDirectory>./TestResults</ResultsDirectory>
    <TestSessionTimeout>600000</TestSessionTimeout>
  </RunConfiguration>
  <DataCollectionRunSettings>
    <DataCollectors>
      <DataCollector friendlyName="XPlat Code Coverage">
        <Configuration>
          <Format>cobertura</Format>
          <Exclude>[*]*.Migrations.*</Exclude>
        </Configuration>
      </DataCollector>
    </DataCollectors>
  </DataCollectionRunSettings>
</RunSettings>

# Use runsettings file
dotnet test --settings test.runsettings

Test Failure Analysis

Common Failure Patterns

Pattern	Cause	Fix
Assert.Equal failed	Expected != Actual	Check logic, verify test data
NullReferenceException	Null not handled	Add null checks, verify setup
TimeoutException	Test too slow	Optimize or increase timeout
ObjectDisposedException	Using disposed object	Fix lifetime management
InvalidOperationException	Invalid state	Check test setup/order

Debugging Failed Tests

# Run single failing test with detailed output
dotnet test --filter "FullyQualifiedName~FailingTest" -v d

# Enable blame mode to catch hangs
dotnet test --blame

# Blame with hang detection
dotnet test --blame-hang --blame-hang-timeout 60s

Watch Mode

# Run tests on file changes
dotnet watch test

# Watch specific project
dotnet watch --project tests/MyApp.Tests test

# Watch with filter
dotnet watch test --filter "Category=Unit"

CI/CD Integration

Exit Codes

Code	Meaning
0	All tests passed
1	Tests failed
2	Command line error

CI Examples

# Azure DevOps
- task: DotNetCoreCLI@2
  inputs:
    command: test
    arguments: '--configuration Release --logger trx'

# GitHub Actions
- run: dotnet test --configuration Release --logger "trx;LogFileName=test-results.trx"

See test-filtering.md for advanced filtering patterns.