exec karma --check-config
! stdout .
cmp stderr stderr.txt

-- stderr.txt --
level=INFO msg="Reading configuration file" path=karma.yaml
level=INFO msg="Version: dev"
level=INFO msg="Configured Alertmanager source" name=default cluster=default uri=https://127.0.0.1:9093 proxy=false readonly=false
level=INFO msg="Configuration is valid"
-- karma.yaml --
alertmanager:
  servers:
    - name: default
      uri: https://127.0.0.1:9093
silences:
  expired: -1s
