chore: move notification test, other refactoring (#111)

src/__test__/notification-test.ts

@@ -0,0 +1,16 @@
+import {Link} from '../store/model';
+import {sendNotification} from '../notification';
+
+const link: Link = {
+	brand: 'brand',
+	cartUrl: 'http://example.com/',
+	captchaLabels: ['captcha'],
+	model: 'model',
+	oosLabels: ['out of stock'],
+	url: 'http://example.com/'
+};
+
+/**
+ * Send test email.
+ */
+sendNotification(link.cartUrl ?? link.url, link);