Test the bind form of Sync.sync.

test/unit/test_Sync.js

@@ -13,6 +13,12 @@ function slowAdd(onComplete, wait, num1, num2) {
   setTimeout(function() onComplete(num1 + num2), wait);
 }
 
+function slowThisGet(onComplete, wait, prop) {
+  // NB: this[prop] could be different if accessed after waiting
+  let ret = this[prop];
+  setTimeout(function() onComplete(ret), wait);
+}
+
 // Test the built-in Sync.sleep method.
 function test_Sync_sleep() {
   let duration = time(function() {
@@ -39,6 +45,15 @@ function test_Sync_sync() {
   do_check_true(duration >= 100);
 }
 
+// Check that the non-Function.prototype version of syncBind works
+function test_Sync_sync_bind() {
+  let duration = time(function() {
+    let val = Sync.sync(slowThisGet, { foo: "bar" })(100, "foo");
+    do_check_eq(val, "bar");
+  });
+  do_check_true(duration >= 100);
+}
+
 // Make sure the exported Sync object/function has Function properties
 function test_function_Sync() {
   // We can't check the functions directly because the Function object for Sync