dsc/examples/assertion.dsc.yaml

# Example configuration that uses assertions to validate the environment before running the configuration.
$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
resources:
- name: current user registry
  type: Microsoft.Windows/Registry
  properties:
    keyPath: HKCU\example
    _exist: true
  dependsOn:
  - "[resourceId('Microsoft.DSC/Assertion','my assertions')]"
- name: my assertions
  type: Microsoft.DSC/Assertion
  properties:
    $schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
    resources:
    - name: os
      type: Microsoft/OSInfo
      properties:
        family: Windows
    - name: system root
      type: Microsoft.Windows/Registry
      properties:
        keyPath: HKLM\Software\Microsoft\Windows NT\CurrentVersion
        valueName: SystemRoot
        valueData:
          # this is deliberately set to L: drive so that the assertion fails
          String: L:\Windows