RSpec.describe ApplicationMailer, type: :mailer do describe 'dealing with invalid emails' do let(:dossier) { create(:dossier, procedure: build(:simple_procedure)) } subject { DossierMailer.notify_new_draft(dossier) } describe 'invalid emails are not sent' do before do allow_any_instance_of(DossierMailer) .to receive(:notify_new_draft) .and_raise(Net::SMTPSyntaxError) end it { expect(subject.message).to be_an_instance_of(ActionMailer::Base::NullMail) } end describe 'valid emails are sent' do it { expect(subject.message).not_to be_an_instance_of(ActionMailer::Base::NullMail) } end end end