Adding test framework install to Powershell's run-tests.ps1

In the standard Linux install of Powershell the test module Pester is NOT included. Without it run-tests.ps1 won’t work.

What else must be added to run-tests.ps1 other than adding Install-Module -Name Pester -Force -SkipPublisherCheck at the top? For example, is it worthwhile testing for the existence of the module before installing or can that check be left to the Install-Module tool itself?

How do I test for the presence of Pester? One could install if not present and run Update-Module -Name Pester if it is. @ErikSchierboom? Oh, and to make things interesting, I’ve just noticed that one needs to sudo the install (and probably the update.)

In How do I check if a PowerShell module is installed? - Stack Overflow there is sample code to check if a module is installed.

The PR is passing all checks now. Only installs Pester if it’s missing and so will only install in Linux because it’s not missing in Windows.