Should is a command that performs our tests or assertions in our script. It is used for comparing objects and throwing failures when the test is expected to fail. We use Should inside of It blocks in the test script. Should also has different operators for performing tests.
Pester is a framework designed for validating and testing your PowerShell commands, whether they are in functions, cmdlets, modules, or scripts. You write your tests to make sure your PowerShell code does what it is supposed to, or use it to validate changes made to an existing script.