test_expect_success 'usage shown without sub-command' '
test_expect_code 129 git commit-graph 2>err &&
- ! grep error: err
+ grep usage: err
'
test_expect_success 'usage shown with an error on unknown sub-command' '
cat >expect <<-\EOF &&
- error: unrecognized subcommand: unknown
+ error: unknown subcommand: `unknown'\''
EOF
test_expect_code 129 git commit-graph unknown 2>stderr &&
grep error stderr >actual &&