title: Pester custom error text
body: <p>Does anyone know if Pester supports custom error texts?</p>
  
  <p>Lets say I've the following test:</p>
  
  <pre><code>Describe "Get-HelloWorld" {
      It "outputs 'Hello world!'" {
          Get-HelloWorld | Should Be 'Hello world!'
      }
  }
  </code></pre>
  
  <p>Is there a way that I can set some custom error message if <code>Get-HelloWorld</code> returns another string than "Hello World"? </p>
  
  <p>Thx</p>