Add integration tests to check for preservation of this

Author: Luca Forstner

packages/integration-tests/suites/public-api/instrumentation/eventListener-this-preservation/subject.js

@@ -0,0 +1,24 @@
+const btn = document.createElement('button');
+btn.id = 'btn';
+document.body.appendChild(btn);
+
+const functionListener = function () {
+  functionCallback(this.constructor.name);
+};
+
+class EventHandlerClass {
+  handleEvent() {
+    classInstanceCallback(this.constructor.name);
+  }
+}
+const objectListener = new EventHandlerClass();
+
+// Attach event listeners a few times for good measure
+
+btn.addEventListener('click', functionListener);
+btn.addEventListener('click', functionListener);
+btn.addEventListener('click', functionListener);
+
+btn.addEventListener('click', objectListener);
+btn.addEventListener('click', objectListener);
+btn.addEventListener('click', objectListener);

packages/integration-tests/suites/public-api/instrumentation/eventListener-this-preservation/test.ts

@@ -0,0 +1,24 @@
+import { expect } from '@playwright/test';
+
+import { sentryTest } from '../../../../utils/fixtures';
+
+sentryTest('Event listener instrumentation preserves "this" context', async ({ getLocalTestPath, page }) => {
+  const url = await getLocalTestPath({ testDir: __dirname });
+  await page.goto(url);
+
+  let assertions = 0;
+
+  await page.exposeFunction('functionCallback', (thisInstanceName: unknown) => {
+    expect(thisInstanceName).toBe('HTMLButtonElement');
+    assertions = assertions + 1;
+  });
+
+  await page.exposeFunction('classInstanceCallback', (thisInstanceName: unknown) => {
+    expect(thisInstanceName).toBe('EventHandlerClass');
+    assertions = assertions + 1;
+  });
+
+  await page.evaluate('document.getElementById("btn").click()');
+
+  expect(assertions).toBe(2);
+});