Invoke-TDDworkflow.ps1

#Requires -Version 4.0 -Modules Pester
# http://mikefrobbins.com/2016/05/12/why-isnt-test-driven-development-more-widely-adopted-and-accepted-by-the-powershell-community/
function Invoke-TDDWorkflow {
    [CmdletBinding()]
    param (
        [ValidateScript({
          If (Test-Path -Path $_ -PathType Container) {
            $true
          }
          else {
            Throw "'$_' is not a valid directory."
          }
        })]
        [string]$Path = (Get-Location),
        [ValidateNotNullOrEmpty()]
        [int]$Seconds = 30
    )
    $Complete = $false

    Add-Type -AssemblyName System.Windows.Forms
    Clear-Host
    while (-not $Complete) {
        if ((Invoke-Pester -Script $Path -Quiet -PassThru -OutVariable Results).FailedCount -eq 0) {
            if ([System.Windows.Forms.MessageBox]::Show('Is the code complete?', 'Status', 4, 'Question', 'Button2') -eq 'Yes') {
                $Complete = $true
            }
            else {
                $Complete = $False
                Write-Output "Write a failing unit test for a simple feature that doesn't yet exist."
                if ($psISE) {
                    [System.Windows.Forms.MessageBox]::Show('Click Ok to Continue')
                }
                else {
                    Write-Output 'Press any key to continue ...'
                    $Host.UI.RawUI.ReadKey('NoEcho, IncludeKeyDown') | Out-Null
                }
                Clear-Host
            }
        }
        else {
            Write-Output "Write code until unit test: '$(@($Results.TestResult).Where({$_.Passed -eq $false}, 'First', 1).Name)' passes"
            Start-Sleep -Seconds $Seconds
            Clear-Host
        }
    }
}