medium-requirements-invokesimple.ps1

function Invoke-Requirement {
    [CmdletBinding()]
    Param(
        [Parameter(Mandatory, ValueFromPipeline)]
        [ValidateNotNullOrEmpty()]
        [Requirement[]]$Requirement
    )

    process {
        $result = &$_.Test
        if (-not $result) {
            &$_.Set | Out-Null
            $result = &$_.Test
            if (-not $result) {
                throw "Validation failed for '$($_.Name)'"
            }
        }
    }
}

$requirements | Invoke-Requirement