xUnit Assert.All() async

Question

I have this example test using xUnit:

    [Fact]
    public void SomeTest()
    {
        Assert.All(itemList, async item=>
                {
                    var i = await Something(item);
                    Assert.Equal(item,i);
                });
    }

Is there a good solution to make the whole test async/awaitable?

Solution

There's no built-in async All. You can use Task.WhenAll:

[Fact]
public async Task SomeTest()
{
    var itemList = ...;
    var results = await Task.WhenAll(itemList.Select(async item =>
    {
        var i = await Something(item);
        return i;
    }));
    Assert.All(results, result => Assert.Equal(1, result));
}

Comments

[B Bulfin]

@Igor: That change only makes SomeTest() superficially awaitable. Assert.All() still behaves the same way.

[Stephen Cleary]

Good approach, but var results = await Task.WhenAll(tasks) gives you a nice result array to work with.

[Eli Arbel]

Thanks @StephenCleary. Edited.