Assert the login form shows (or does not show) its error, optionally with a given text. The error is #t3-login-error ("Your login attempt did not succeed").
Examples
Then I should see a login error
Then I should not see a login error
And I should see the login error "Your login attempt did not succeed"
Then we should see a login error
And I should not see the login error "Your login attempt did not succeed"
Pattern
Then(/^(I |we )*should( not)* see (?:a|the) login error(?: "([^"]*)")?$/, …)
Part of @webship-js/typo3-steps (github.com/webship/typo3-steps), a step pack for Webship-js 2.0.x.