Test Exception thrown in async Task [duplicate]

Question

I try to test this async method:

public static async Task SimpleAsync() { await Task.Delay(10); throw new Exception("Should fail."); }

with:

Assert.Throws<Exception>(async () => await AsyncUnderTest.SimpleAsync());

but NUnit doesn't run:

Async void methods are not supported

How should I test the exception in NUnit?
I wonder how to include the Task return value in the lambda expression?

This question is much clearer and educational then the chaotic so-called "duplicate" question.

Gerard · Accepted Answer · 2024-06-11 13:29:35Z

Indeed:

Assert.ThrowsAsync<Exception>(async Task () => await AsyncUnderTest.SimpleAsync());

or also:

Assert.ThrowsAsync<Exception>(async () => await AsyncUnderTest.SimpleAsync());

So async void is allowed in the lambda expression when using ThrowsAsync it is not allowed when using Throws.

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