Rename richtext controller and write specs

spec/javascripts/stimulus/add_blank_to_link_controller_test.js

@@ -0,0 +1,24 @@
+/**
+ * @jest-environment jsdom
+ */
+
+import { Application } from "stimulus";
+import add_blank_to_link_controller from "../../../app/webpacker/controllers/add_blank_to_link_controller";
+
+describe("AddBlankToLink", () => {
+  beforeAll(() => {
+    const application = Application.start();
+    application.register("add-blank-to-link", add_blank_to_link_controller);
+  });
+
+  describe("#add-blank-to-link", () => {
+    beforeEach(() => {
+      document.body.innerHTML = `<div data-controller="add-blank-to-link"><a href="www.ofn.com">www.ofn.com</a></div>`;
+    });
+
+    it("adds target='_blank' to anchor tags", () => {
+      const anchorTag = document.querySelector('a')
+      expect(anchorTag.getAttribute('target')).toBe("_blank");
+    });
+  });
+});