Mastering Windows PowerShell Scripting - Third Edition

Testing for errors

The -Throw assertion is used to test whether a block of code throws a terminating error. Throw has a number of different usage scenarios. The simplest is detecting whether a terminating error (of any kind) is thrown at all:

function Invoke-Something {    throw}Describe Invoke-Something { 
    It 'Throws a terminating error' { 
        { Invoke-Something } | Should Throw 
    } 
} 

When testing for terminating errors, the subject of the test is placed in a script block (curly braces).

The next step might be to get Pester to test the error message, to ensure that the right error is thrown:

function Invoke-Something {    throw 'an error'}Describe Invoke-Something { It 'Throws a terminating error' { { Invoke-Something } | Should Throw 'an error' } } ...