Windows 10 and Server 2016 automatically install a module called Pester which is used for testing code. Its the foundation of Test Driven Development or Behaviour Driven Development using PowerShell.
The version installed by default is 3.4.0.
Pester is originally an open source module that has been incorporated into Windows. The latest version from the PowerShell Gallery is 4.0.2
Normally you’d use Update-Module to install the new version BUT you didn’t install pester from the gallery using Install-Module so you’ll get a big fat error message.
The answer is to use
Install-Module pester –Force
You might still get an error message about the Pester module not being catalog signed. if you do and still want the latest version then use
Install-Module pester -Force -SkipPublisherCheck