Improve assert.async Function to Handle Type Checking

[zixinyin]

• QUnit version: 2.19.4
• Which environment are you using?: browser
• **How are you running QUnit? **: Karma

What are you trying to do?

Currently, using a string instead of a number as an argument for assert.async in QUnit causes the test page to hang indefinitely without providing diagnostic messages. To enhance this function and improve diagnostics, we propose adding type checking.

Code that reproduces the problem:

QUnit.test("Test type checking for async", function(assert) {
    assert.async("the test should fail");
});

What did you expect to happen?

While running the code above, the test should fail and deliver proper diagnostics message.

What actually happened?

The test hang indefinitely.