# Raises an error if label custom color config is missing a value
! exec karma --config.file=karma.yaml
! stdout .
cmp stderr stderr.txt

-- stderr.txt --
level=ERROR msg="Execution failed" error="custom label color for 'region' is missing 'value' or 'value_re'"
-- karma.yaml --
alertmanager:
  servers:
    - name: default
      uri: https://127.0.0.1:9093
labels:
  color:
    custom:
      region:
        - color: "#736598"
