cli/command: use more descriptive const in test
cli/command: use more descriptive const in test

On failures, the output wasn't clear which side was "expected" and
which side was "actual".

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

thaJeztah/cli,thaJeztah/cli,docker/cli,docker/cli