Assert a system message (joomla-alert) is (or is not) showing, optionally of one type (success, info, notice, warning or error) and containing some text. The messages are the same on the site and in the administrator.
Examples
Then I should see a success message "Article saved."
Then I should see an error message "Save failed"
Then we should see a warning message "Username and password do not match"
And I should not see an info message
Then I should see the system message "saved"
Pattern
Then(/^(I |we )*should( not)* see (?:a|an|the) (?:(success|info|notice|warning|error) )?(?:system )?message(?: "([^"]*)")?$/, …)
Part of @webship-js/joomla-steps (github.com/webship/joomla-steps), a step pack for Webship-js 2.0.x.