how to test asynchronous methods using nunit

Question

How to test asynchronous methods using nunit?

What problem are you having? You just test them; and check for the thing they are doing. I mean, no matter what you're going to need to wait. It's just a matter of seeing if you can get it to notify you, so you don't need to poll. May or may not be possible. — Noon Silk, Mar 12 '10 at 09:26
Near duplicate of ["How do I test an async method with NUnit, eventually with another framework?"](http://stackoverflow.com/questions/12191831/how-do-i-test-an-async-method-with-nunit-eventually-with-another-framework) — chwarr, May 17 '14 at 05:01
5 upvotes for a 7 word question showing no research effort? _[How do I ask a good question?](http://stackoverflow.com/help/how-to-ask)_. I'm jealous ;) — , Sep 11 '15 at 09:12
Does this answer your question? [How do I test an async method with NUnit (or possibly with another framework)?](https://stackoverflow.com/questions/12191831/how-do-i-test-an-async-method-with-nunit-or-possibly-with-another-framework) — ggorlen, Oct 05 '22 at 05:51

Namo · Accepted Answer · 2013-11-29T13:26:36.950

If you have .NET’s version 5 of the C# compiler then you can use new async and await keywords. attach the link : http://simoneb.github.io/blog/2013/01/19/async-support-in-nunit/

If you can using closure with anonymous lambda function, using thread synchronization.

eg)

[TestFixture]
class SomeTests
{
    [Test]
    public void AsyncTest()
    {
        var autoEvent = new AutoResetEvent(false); // initialize to false

        var Some = new Some();
        Some.AsyncFunction(e =>
        {
            Assert.True(e.Result);
            autoEvent.Set(); // event set
        });
        autoEvent.WaitOne(); // wait until event set
    }

}

score 2 · Answer 2 · answered May 11 '17 at 17:08

You could use NUnits Delayed Constraint

[TestFixture]
class SomeTests
{
    [Test]
    public void AsyncTest()
    {
        var result = false;
        var Some = new Some();
        Some.AsyncFunction(e =>
        {
            result = e.Result;
        });

        Assert.That(() => result, Is.True.After(1).Minutes.PollEvery(500).MilliSeconds);
    }

}

This example is for NUnit 3.6 but earlier versions also support Delayed Constraint, but lookup it up as the syntax is different.

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how to test asynchronous methods using nunit

2 Answers2