- project:
    name: test_variable_default_values
    jobs:
        - 'variable_default_values':
            defined_var: '7'

- job-template:
    name: 'variable_default_values'
    properties:
      - build-discarder:
          days-to-keep: '{undefined_var|+1}'
          num-to-keep: '{defined_var|+1}'
          artifact-days-to-keep: '{undefined_var|-1}'
          artifact-num-to-keep: '{defined_var|-1}'
    builders:
      - shell: |
          echo "{{defined_var|+1}}"
          echo "{{defined_var|-1}}"
          echo "{{undefined_var|+1}}"
          echo "{{undefined_var|-1}}"