xUnit2012 Warning

Do not use Enumerable.Any() to check if a value exists in a collection

Cause

A violation of this rule occurs when Enumerable.Any is used to check if a value matching a predicate exists in a collection.

Reason for rule

There are specialized assertions for checking for elements in collections.

How to fix violations

Replace Assert.True with Assert.Contains and/or Assert.False with Assert.DoesNotContain.

Examples

Violates

using System.Linq;
using Xunit;

public class xUnit2012
{
    [Fact]
    public void TestMethod()
    {
        var result = new[] { "Hello" };

        Assert.True(result.Any(value => value.Length == 5));
    }
}

Does not violate

using Xunit;

public class xUnit2012
{
    [Fact]
    public void TestMethod()
    {
        var result = new[] { "Hello" };

        Assert.Contains(result, value => value.Length == 5);
    }
}