v2 v3   Warning

xUnit2003

"Do not use equality check to test for null value"

Cause

A violation of this rule occurs when Assert.Equal, AssertNotEqual, Assert.StrictEqual, or Assert.NotStrictEqual are used with null.

Reason for rule

Assert.Null and Assert.NotNull should be used when checking against null.

How to fix violations

To fix a violation of this rule, replace the offending asserts with Assert.Null or Assert.NotNull.

Examples

Violates

using Xunit;

public class xUnit2003
{
    [Fact]
    public void TestMethod()
    {
        var result = "Hello world!";

        Assert.Equal(null, result);
    }
}

Does not violate

using Xunit;

public class xUnit2003
{
    [Fact]
    public void TestMethod()
    {
        var result = "Hello world!";

        Assert.Null(result);
    }
}