assert: fix CallTracker calls wraps the function causes the original …

lib/internal/assert/calltracker.js

@@ -4,6 +4,7 @@ const {
   ArrayPrototypePush,
   Error,
   FunctionPrototype,
+  ObjectDefineProperty,
   ReflectApply,
   SafeSet,
 } = primordials;
@@ -46,7 +47,7 @@ class CallTracker {
     const callChecks = this.#callChecks;
     callChecks.add(context);
 
-    return function() {
+    function callsFn() {
       context.actual++;
       if (context.actual === context.exact) {
         // Once function has reached its call count remove it from
@@ -59,7 +60,13 @@ class CallTracker {
         callChecks.add(context);
       }
       return ReflectApply(fn, this, arguments);
-    };
+    }
+
+    ObjectDefineProperty(callsFn, 'length', {
+      value: fn.length
+    });
+
+    return callsFn;
   }
 
   report() {

test/parallel/test-assert-calltracker-calls.js

@@ -78,3 +78,17 @@ assert.throws(
   callsNoop();
   tracker.verify();
 }
+
+{
+  function func() {}
+  const tracker = new assert.CallTracker();
+  const callsfunc = tracker.calls(func);
+  assert.strictEqual(func.length, callsfunc.length);
+}
+
+{
+  function func(a, b, c = 2) {}
+  const tracker = new assert.CallTracker();
+  const callsfunc = tracker.calls(func);
+  assert.strictEqual(func.length, callsfunc.length);
+}