test_runner: do not throw on mocked clearTimeout()

PR-URL: #54005
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>

lib/internal/test_runner/mock/mock_timers.js

@@ -304,7 +304,7 @@ class MockTimers {
   }
 
   #clearTimer(timer) {
-    if (timer.priorityQueuePosition !== undefined) {
+    if (timer?.priorityQueuePosition !== undefined) {
       this.#executionQueue.removeAt(timer.priorityQueuePosition);
       timer.priorityQueuePosition = undefined;
     }

test/parallel/test-runner-mock-timers.js

@@ -257,6 +257,13 @@ describe('Mock Timers Test Suite', () => {
 
         assert.strictEqual(fn.mock.callCount(), 0);
       });
+
+      it('clearTimeout does not throw on null and undefined', (t) => {
+        t.mock.timers.enable({ apis: ['setTimeout'] });
+
+        nodeTimers.clearTimeout();
+        nodeTimers.clearTimeout(null);
+      });
     });
 
     describe('setInterval Suite', () => {
@@ -305,6 +312,13 @@ describe('Mock Timers Test Suite', () => {
 
         assert.strictEqual(fn.mock.callCount(), 0);
       });
+
+      it('clearInterval does not throw on null and undefined', (t) => {
+        t.mock.timers.enable({ apis: ['setInterval'] });
+
+        nodeTimers.clearInterval();
+        nodeTimers.clearInterval(null);
+      });
     });
 
     describe('setImmediate Suite', () => {
@@ -372,6 +386,15 @@ describe('Mock Timers Test Suite', () => {
       });
     });
 
+    describe('clearImmediate Suite', () => {
+      it('clearImmediate does not throw on null and undefined', (t) => {
+        t.mock.timers.enable({ apis: ['setImmediate'] });
+
+        nodeTimers.clearImmediate();
+        nodeTimers.clearImmediate(null);
+      });
+    });
+
     describe('timers/promises', () => {
       describe('setTimeout Suite', () => {
         it('should advance in time and trigger timers when calling the .tick function multiple times', async (t) => {