diff --git a/test/TestExpectations.json b/test/TestExpectations.json
index 6d127145b2d..d77f1a49a3f 100644
--- a/test/TestExpectations.json
+++ b/test/TestExpectations.json
@@ -47,12 +47,6 @@
     "parameters": ["webDriverBiDi"],
     "expectations": ["SKIP"]
   },
-  {
-    "testIdPattern": "[headful.spec] *",
-    "platforms": ["darwin", "linux", "win32"],
-    "parameters": ["firefox"],
-    "expectations": ["SKIP"]
-  },
   {
     "testIdPattern": "[idle_override.spec] *",
     "platforms": ["darwin", "linux", "win32"],
diff --git a/test/src/headful.spec.ts b/test/src/headful.spec.ts
index af7364d4149..67ae9f335ee 100644
--- a/test/src/headful.spec.ts
+++ b/test/src/headful.spec.ts
@@ -22,8 +22,8 @@ describe('headful tests', function () {
    */
   this.timeout(20_000);
 
-  let headfulOptions: PuppeteerLaunchOptions | undefined;
-  let headlessOptions: PuppeteerLaunchOptions & {headless: boolean};
+  let headfulOptions: PuppeteerLaunchOptions & {headless: false};
+  let headlessOptions: PuppeteerLaunchOptions & {headless: true};
 
   const browsers: Array<() => Promise<void>> = [];
 
@@ -32,10 +32,10 @@ describe('headful tests', function () {
       skipLaunch: true,
     });
     headfulOptions = Object.assign({}, defaultBrowserOptions, {
-      headless: false,
+      headless: false as const,
     });
     headlessOptions = Object.assign({}, defaultBrowserOptions, {
-      headless: true,
+      headless: true as const,
     });
   });