NUnit2009

The same value has been provided as both the actual and the expected argument

Description

The same value has been provided as both the actual and the expected argument. This indicates a coding error.

Motivation

To bring developers' attention to a situation in which their code may not be operating as expected and their test may not be testing what they expect.

How to fix violations

Sample Violation

[Test]
public void NUnit2009SampleTest()
{
    var x = 1;
    Assert.That(x, Is.EqualTo(x));
}

Explanation

In the above example, the test will always be correct, because we're comparing the same value. That is to say, we're not actually testing anything.

Fix

Ensure the expected and actual values come from different places.

[Test]
public void NUnit2009SampleTest()
{
    var x = 1;
    Assert.That(x, Is.EqualTo(1));
}

Configure severity

Via ruleset file

Configure the severity per project, for more info see MSDN.

Via .editorconfig file

# NUnit2009: The same value has been provided as both the actual and the expected argument
dotnet_diagnostic.NUnit2009.severity = chosenSeverity

where chosenSeverity can be one of none, silent, suggestion, warning, or error.

Via #pragma directive

#pragma warning disable NUnit2009 // The same value has been provided as both the actual and the expected argument
Code violating the rule here
#pragma warning restore NUnit2009 // The same value has been provided as both the actual and the expected argument

Or put this at the top of the file to disable all instances.

#pragma warning disable NUnit2009 // The same value has been provided as both the actual and the expected argument

Via attribute [SuppressMessage]

[System.Diagnostics.CodeAnalysis.SuppressMessage("Assertion",
    "NUnit2009:The same value has been provided as both the actual and the expected argument",
    Justification = "Reason...")]