Testing with Pester

Pester is a framework for executing tests. It includes tools to define and execute test cases against anything that can be written in PowerShell.

This part of the chapter focuses on Pester 5, the latest major release. Pester 5 is not installed by default; Windows ships with Pester 3.4. This pre-installed version can be ignored. If Pester is already installed, Force must be used and the publisher check must be skipped. Otherwise, the two additional parameters below can be ignored:

Install-Module Pester -Force -SkipPublisherCheck

The SkipPublisherCheck parameter is required as Pester has changed maintainer since the version shipped with Windows was released. The certificate issued to the pre-installed version differs from the certificate issued to the current version.

Pester can be used to write tests for code, systems, and everything in between. Pester is implemented as what is known as a Domain-Specific Language (DSL). It has specific functions...