How to understand example about exceptions

[lszczygielek]

I'm looking at https://fluentassertions.com/exceptions/ and I understand example like:

Action act = () => subject.Foo2("Hello");

act.Should().Throw<InvalidOperationException>()
    .WithInnerException<ArgumentException>()
    .WithMessage("whatever");

Then I look at paragraph about async and I see:

Func<Task> act = () => asyncObject.ThrowAsync<ArgumentException>();
await act.Should().ThrowAsync<InvalidOperationException>();
await act.Should().NotThrowAsync();

And I don't know what it is. What is asyncObject and why ThrowAsync is called on it - it doesn't look like method, or I'm missing something?

In my tests I use:

Func<Task<MyType>> func = () => myObject.MyMethodAsync(1).;
await func.Should().ThrowAsync<Exception>();

It works, but when I compare it with example from documentation, I have doubts if I'm doing OK.

[dennisdoomen]

In this example, the asyncObject is an instance of some type that has an async method names ThrowAsync.

[jnyrup]

I have written myself a note to see if this documentation can be even more clear.