PowerShell-master/.github/instructions/pester-set-itresult-pattern.instructions.md

metadata

applyTo:
  - '**/*.Tests.ps1'

Pester Set-ItResult Pattern for Pending and Skipped Tests

Purpose

This instruction explains when and how to use Set-ItResult in Pester tests to mark tests as Pending or Skipped dynamically within test execution.

When to Use Set-ItResult

Use Set-ItResult when you need to conditionally mark a test as Pending or Skipped based on runtime conditions that can't be determined at test definition time.

Pending vs Skipped

Pending: Use for tests that should be enabled but temporarily can't run due to:

• Intermittent external service failures (network, APIs)
• Known bugs being fixed
• Missing features being implemented
• Environmental issues that are being resolved

Skipped: Use for tests that aren't applicable to the current environment:

• Platform-specific tests running on wrong platform
• Tests requiring specific hardware/configuration not present
• Tests requiring elevated permissions when not available
• Feature-specific tests when feature is disabled

Pattern

Basic Usage

It "Test description" {
    if ($shouldBePending) {
        Set-ItResult -Pending -Because "Explanation of why test is pending"
        return
    }
    
    if ($shouldBeSkipped) {
        Set-ItResult -Skipped -Because "Explanation of why test is skipped"
        return
    }
    
    # Test code here
}

Important: Always Return After Set-ItResult

After calling Set-ItResult, you must return from the test to prevent further execution:

It "Test that checks environment" {
    if ($env:SKIP_TESTS -eq 'true') {
        Set-ItResult -Skipped -Because "SKIP_TESTS environment variable is set"
        return  # This is required!
    }
    
    # Test assertions
    $result | Should -Be $expected
}

Why? Without return, the test continues executing and may fail with errors unrelated to the pending/skipped condition.

Examples from the Codebase

Example 1: Pending for Intermittent Network Issues

It "Validate Update-Help for module" {
    if ($markAsPending) {
        Set-ItResult -Pending -Because "Update-Help from the web has intermittent connectivity issues. See issues #2807 and #6541."
        return
    }
    
    Update-Help -Module $moduleName -Force
    # validation code...
}

Example 2: Skipped for Missing Environment

It "Test requires CI environment" {
    if (-not $env:CI) {
        Set-ItResult -Skipped -Because "Test requires CI environment to safely install Pester"
        return
    }
    
    Install-CIPester -ErrorAction Stop
}

Example 3: Pending for Platform-Specific Issue

It "Clear-Host works correctly" {
    if ($IsARM64) {
        Set-ItResult -Pending -Because "ARM64 runs in non-interactively mode and Clear-Host does not work."
        return
    }
    
    & { Clear-Host; 'hi' } | Should -BeExactly 'hi'
}

Example 4: Skipped for Missing Feature

It "Test ACR authentication" {
    if ($env:ACRTESTS -ne 'true') {
        Set-ItResult -Skipped -Because "The tests require the ACRTESTS environment variable to be set to 'true' for ACR authentication."
        return
    }
    
    $psgetModuleInfo = Find-PSResource -Name $ACRTestModule -Repository $ACRRepositoryName
    # test assertions...
}

Alternative: Static -Skip and -Pending Parameters

For conditions that can be determined at test definition time, use the static parameters instead:

# Static skip - condition known at definition time
It "Windows-only test" -Skip:(-not $IsWindows) {
    # test code
}

# Static pending - always pending
It "Test for feature being implemented" -Pending {
    # test code that will fail until feature is done
}

Use Set-ItResult when:

• Condition depends on runtime state
• Condition is determined inside a helper function
• Need to check multiple conditions sequentially

Use static parameters when:

• Condition is known at test definition
• Condition doesn't change during test run
• Want Pester to show the condition in test discovery

Best Practices

1. Always include -Because parameter with a clear explanation
2. Always return after Set-ItResult to prevent further execution
3. Reference issues or documentation when relevant (e.g., "See issue #1234")
4. Be specific in the reason - explain what's wrong and what's needed
5. Use Pending sparingly - it indicates a problem that should be fixed
6. Prefer Skipped over Pending when test truly isn't applicable

Common Mistakes

❌ Mistake 1: Forgetting to Return

It "Test" {
    if ($condition) {
        Set-ItResult -Pending -Because "Reason"
        # Missing return - test code will still execute!
    }
    $value | Should -Be $expected  # This runs and fails
}

❌ Mistake 2: Vague Reason

Set-ItResult -Pending -Because "Doesn't work"  # Too vague

✅ Correct:

It "Test" {
    if ($condition) {
        Set-ItResult -Pending -Because "Update-Help has intermittent network timeouts. See issue #2807."
        return
    }
    $value | Should -Be $expected
}

See Also

• Pester Documentation: Set-ItResult
• Pester Documentation: It
• Examples in the codebase:
  • test/powershell/Host/ConsoleHost.Tests.ps1
  • test/infrastructure/ciModule.Tests.ps1
  • tools/packaging/releaseTests/sbom.tests.ps1