xUnit2017 Warning

Do not use Contains() to check if a value exists in a collection

Cause

A violation of this rule occurs when Enumerable.Contains() is used to check if a value exists in a collection.

Reason for rule

There are specialized assertions for checking for elements in collections.

How to fix violations

Use Assert.Contains or Assert.DoesNotContain instead.

Examples

Violates

using System.Linq;
using Xunit;

public class xUnit2017
{
    [Fact]
    public void TestMethod()
    {
        var result = new[] { "foo", "bar" };

        Assert.True(result.Contains("foo"));
    }
}

Does not violate

using Xunit;

public class xUnit2017
{
    [Fact]
    public void TestMethod()
    {
        var result = new[] { "foo", "bar" };

        Assert.Contains("foo", result);
    }
}