Added tests for the link replacement logic

tests/lib/popup-links.spec.ts

@@ -0,0 +1,75 @@
+import { randomString } from "$tests/utils";
+import { initializeLinksReplacement } from "$lib/popup-links";
+
+describe('popup-links', () => {
+  let expectedPath = '';
+  let testLink: HTMLAnchorElement = document.createElement('a');
+  let disconnectCallback: (() => void) | null = null;
+
+  function fireEventAt(target: EventTarget, eventName: string) {
+    target.dispatchEvent(new Event(eventName, {bubbles: true}));
+  }
+
+  beforeEach(() => {
+    expectedPath = `/test/${randomString()}`;
+    testLink.href = expectedPath;
+    document.body.append(testLink);
+  });
+
+  afterEach(() => {
+    if (disconnectCallback) {
+      disconnectCallback();
+      disconnectCallback = null;
+    }
+  });
+
+  it('should replace link on any mouse button down', () => {
+    disconnectCallback = initializeLinksReplacement();
+    fireEventAt(testLink, "mousedown");
+
+    const resultUrl = new URL(testLink.href);
+
+    expect(resultUrl.searchParams.get('path')).toBe(expectedPath);
+  });
+
+  it('should replace link when link is pressed by keyboard or clicked', () => {
+    disconnectCallback = initializeLinksReplacement();
+    fireEventAt(testLink, "click");
+
+    const resultUrl = new URL(testLink.href);
+
+    expect(resultUrl.searchParams.get('path')).toBe(expectedPath);
+  });
+
+  it('should not replace already replaced links', () => {
+    disconnectCallback = initializeLinksReplacement();
+    fireEventAt(testLink, "click");
+    const hrefAfterFirstClick = testLink.href;
+
+    fireEventAt(testLink, "click");
+    const hrefAfterSecondClick = testLink.href;
+
+    expect(hrefAfterFirstClick).toBe(hrefAfterSecondClick);
+  });
+
+  it('should stop replacing links once disconnect is called', () => {
+    const hrefBefore = testLink.href;
+
+    disconnectCallback = initializeLinksReplacement();
+    disconnectCallback();
+    fireEventAt(testLink, "mousedown");
+    fireEventAt(testLink, "click");
+
+    expect(hrefBefore).toBe(testLink.href);
+  });
+
+  it('should not touch links with different origin', () => {
+    testLink.href = "https://external.example.com/" + randomString() + "/";
+
+    const hrefBefore = testLink.href;
+    disconnectCallback = initializeLinksReplacement();
+    fireEventAt(testLink, "click");
+
+    expect(testLink.href).toBe(hrefBefore);
+  });
+});