New Task .Should() extensions

[michal-ciechan]

Wondering if it is worth adding the following 2 extension methods for Task/Task<T> to not need Func<Task> act = .... each time I want to assert the method call with throw an exception.

public static class FluentAssertionExtensions
{
    public static NonGenericAsyncFunctionAssertions Should(this Task task)
    {
        Func<Task> act = () => task;

        return act.Should();
    }

    public static GenericAsyncFunctionAssertions<T> Should<T>(this Task<T> task)
    {
        Func<Task<T>> act = () => task;

        return act.Should();
    }
}

I have been copying this code from project to project and sounds generic enough to be moved.

Probably would be best to create a TaskAssertions / GenericTaskAssertions which either inherit from or delegate to the corresponding [Non]GenericAsyncFunctionsAssertions on the ThrowsAsync etc.

If it is something you guys may be interested in adding let me know, I can create a PR.

This allows me to

[Fact]
public async Task Test()
{
    await _sut.AsyncMethod().Should().ThrowAsync<InvalidOperationException>();
}

Rather than

[Fact]
public async Task Test()
{
    Func<Task> act = () => _sut.AsyncMethod();

    await act.Should().ThrowAsync<InvalidOperationException>();
}

[michal-ciechan]

Also worth considering ValueTask /ValueTask<T> pair. Delegate to ValueTask.AsTask(), and then continue as normal Task

[jnyrup]

The current stand is not to include those assertions.
See e.g. #1001, #1011, #1013 and https://fluentassertions.slack.com/archives/C039Y2H7U/p1581329945017800

But you can write it almost as concise as your desired example by using FluentActions.

using static FluentAssertions.FluentActions;

await Awaiting(() => _sut.AsyncMethod()).Should().ThrowAsync<InvalidOperationException>();