begin converting WakatimeCore

setupTests.ts

@@ -0,0 +1,19 @@
+class BrowserMock {
+  runtime = {
+    getBackgroundPage() {
+      return 'https://background-page.html';
+    },
+    getManifest() {
+      return {
+        version: 'test-version',
+      };
+    },
+    openOptionsPage() {
+      return 'https://options-page.html';
+    },
+  };
+}
+//TODO: Improve mocking
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-expect-error
+window.browser = new BrowserMock();