Pester test for ValidateSet

ValidateSet.Tests.ps1

function foo {
    param (
        [ValidateSet(
                'this',
                'that'
        )]
        [String]$bar
    )
}

Describe 'Testing foo' {
    $parameterInfo = (Get-Command foo).Parameters['bar']
    It 'Has ValidateSet for parameter bar' {
        $parameterInfo.Attributes.Where{ $_ -is [ValidateSet]}.Count | Should be 1
    }
    It 'ValidateSet contains option this' {
        $validateSet = $parameterInfo.Attributes.Where{ $_ -is [ValidateSet]}
        $validateSet.ValidValues -contains 'this' | Should be $true
    }
    It 'ValidateSet contains option this' {
        $validateSet = $parameterInfo.Attributes.Where{ $_ -is [ValidateSet]}
        $validateSet.ValidValues -contains 'somethingElse' | Should be $true
    }
}