Variable name is not displayed after await assertion

Description

It is found that the variable names will not be included in the assertion message when the assertion comes after the await assertion such as NotThrowAsync() and CompleteWithinAsync().

Complete minimal example reproducing the issue

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Threading.Tasks;
using FluentAssertions;
using FluentAssertions.Extensions;

namespace MyUnitTests
{
    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public async Task RunAsyncAssertion()
        {
            // Arrange and Act
            string someText = "Hello";
            Func<Task> myTask = () => Task.Delay(1.Seconds());

            // Assert
            await myTask.Should().CompleteWithinAsync(2.Seconds());
            someText.Should().Be("Hi");
        }
    }
}

Expected behavior:

Assertion failure should be something like Expected someText to be "Hi" with a length of 2, but "Hello" has a length of 5, differs near "ell" (index 1).

Actual behavior:

Expected string to be "Hi" with a length of 2, but "Hello" has a length of 5, differs near "ell" (index 1). Note that string is displayed instead of the variable name someText.

This is not caused by the await keyword used. If the Fluent async assertion is not used, the variable name can be displayed correctly. Example:

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Threading.Tasks;
using FluentAssertions;
using FluentAssertions.Extensions;

namespace MyUnitTests
{
    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public async Task RunAsyncAssertion()
        {
            // Arrange and Act
            string someText = "Hello";
            Func<Task> myTask = () => Task.Delay(1.Seconds());

            // Assert
            await myTask.Invoke();
            someText.Should().Be("Hi");
        }
    }
}

Result: Expected someText to be "Hi" with a length of 2, but "Hello" has a length of 5, differs near "ell" (index 1).

Versions

• Fluent Assertions 6.2.0
• .NET framework 4.7.2

Additional Information

This is my first time submitting an issue on GitHub. Hope it’s alright. 😅

[MullerWasHere]

@jnyrup I’d love to create a PR for it! Also, thanks for the suggestions.

[dennisdoomen]

No, it should be compiled in debug mode. So that confirms it’s an actual bug in FA.