Mastering Windows PowerShell Scripting - Third Edition

Implementing Test

The Test method is used to determine whether Set should be run. DSC invokes Test before Set. The Test method returns a Boolean value.

The Test method must perform the following tests to ascertain the state of this configuration item:

• When Ensure is present, fail if the value does not exist.
• When Ensure is present, fail if the value exists, but the description does not match the requested value.
• When Ensure is absent, fail if the value name exists.
• Otherwise, pass.

The following snippet implements these tests:

[Boolean] Test() {    $key = Get-Item $this.Path    if ($this.Ensure -eq 'Present') {        if ($key.GetValueNames() -notcontains $this.valueName) {            return $false        } return $key.GetValue($this.valueName) -eq $this.Description ...