User mailer spec coverage improvements (#23905)

spec/mailers/user_mailer_spec.rb

@@ -94,4 +94,52 @@ describe UserMailer, type: :mailer do
       expect(mail.body.encoded).to include strike.text
     end
   end
+
+  describe 'webauthn_credential_deleted' do
+    let(:credential) { Fabricate(:webauthn_credential, user_id: receiver.id) }
+    let(:mail) { UserMailer.webauthn_credential_deleted(receiver, credential) }
+
+    it 'renders webauthn credential deleted notification' do
+      receiver.update!(locale: nil)
+      expect(mail.body.encoded).to include I18n.t('devise.mailer.webauthn_credential.deleted.title')
+    end
+
+    include_examples 'localized subject',
+                     'devise.mailer.webauthn_credential.deleted.subject'
+  end
+
+  describe 'suspicious_sign_in' do
+    let(:ip) { '192.168.0.1' }
+    let(:agent) { 'NCSA_Mosaic/2.0 (Windows 3.1)' }
+    let(:timestamp) { Time.now.utc }
+    let(:mail) { UserMailer.suspicious_sign_in(receiver, ip, agent, timestamp) }
+
+    it 'renders suspicious sign in notification' do
+      receiver.update!(locale: nil)
+      expect(mail.body.encoded).to include I18n.t('user_mailer.suspicious_sign_in.explanation')
+    end
+
+    include_examples 'localized subject',
+                     'user_mailer.suspicious_sign_in.subject'
+  end
+
+  describe 'appeal_approved' do
+    let(:appeal) { Fabricate(:appeal, account: receiver.account, approved_at: Time.now.utc) }
+    let(:mail) { UserMailer.appeal_approved(receiver, appeal) }
+
+    it 'renders appeal_approved notification' do
+      expect(mail.subject).to eq I18n.t('user_mailer.appeal_approved.subject', date: I18n.l(appeal.created_at))
+      expect(mail.body.encoded).to include I18n.t('user_mailer.appeal_approved.title')
+    end
+  end
+
+  describe 'appeal_rejected' do
+    let(:appeal) { Fabricate(:appeal, account: receiver.account, rejected_at: Time.now.utc) }
+    let(:mail) { UserMailer.appeal_rejected(receiver, appeal) }
+
+    it 'renders appeal_rejected notification' do
+      expect(mail.subject).to eq I18n.t('user_mailer.appeal_rejected.subject', date: I18n.l(appeal.created_at))
+      expect(mail.body.encoded).to include I18n.t('user_mailer.appeal_rejected.title')
+    end
+  end
 end