jfinckh/pester-tests

Demo for PowerShell Testing with Pester

Install powershell for mac

brew install --cask powershell

Test if powershell is installed:

pwsh

Install pester

pwsh

Install-Module -Name Pester -Force

Run Pester Tests

Invoke-Pester ./A-Test.ps1

Or just run the file:

./A-Test.ps1

Docs

Assertions

Be

Not case sensitive, checks if two objects are the same

$true | Should -Be $true

$true | Should -Not -Be $false

Be exactly

Case sensitive, checks if to objects are the same

$actual | Should -BeExactly "Actual value" # Test will pass

Be false

Asserts that value is false

$false | Should -BeFalse

BeGreaterOrEqual

2 | Should -BeGreaterOrEqual 0

BeGreaterThan

(Get-Date).AddMinutes(5) | Should -BeGreaterThan (Get-Date)

BeIn

27 | Should -BeIn (1..100)

BeLessOrEqual

1 | Should -BeLessOrEqual 10

BeLessThan

$Error.Count | Should -BeLessThan 1

And some more

Check: https://pester.dev/docs/assertions/

Assertions on Files

Check if file exists

$pathToFile | Should -Exist

Check contents of files

$pathToFile | Should -FileContentMatchExactly $content

Custom Assertions

function BeAwesome($ActualValue, [switch] $Negate) {
[bool] $succeeded = $ActualValue -eq 'Awesome'
if ($Negate) { $succeeded = -not $succeeded }

    if (-not $succeeded) {
        if ($Negate) {
            $failureMessage = "{$ActualValue} is Awesome"
        }
        else {
            $failureMessage = "{$ActualValue} is not Awesome"
        }
    }

    return New-Object psobject -Property @{
        Succeeded      = $succeeded
        FailureMessage = $failureMessage
    }
}

Add-ShouldOperator -Name BeAwesome `
-Test $function:BeAwesome `
-Alias 'BA'

PS C:\> "bad" | Should -BeAwesome