create and update actions behave correctly when saving a limerick fails.test/controllers/limericks_controller_test.rb - controller test file."should not create invalid limerick" - name of new create test."should not update invalid limerick" - name of new update test.params to have invalid empty-string values for title and limerick_text:
limerick: { title: '', limerick_text: '' }assert_no_difference - check that the number of Limerick objects in the database has not changed.assert_response - check that the HTTP response has a 422 status code.assert_select - check that the rendered page contains an h1 element with the appropriate text:
create test.update test.assert_not_nil - check that a flash['error'] message was set.rails test -v - command to run tests and generate coverage report.coverage/index.html - coverage report to view in web browser.