NUnit1002

NUnit1002

TestCaseSource should use nameof operator to specify target.

Topic	Value
Id	NUnit1002
Severity	Warning
Enabled	True
Category	Structure
Code	TestCaseSourceUsesStringAnalyzer

Description

TestCaseSource should use nameof operator to specify target.

Motivation

Prevent test rot by ensuring that future renames don't accidentally break tests in an unexpected way. nameof adds some compile-time support in these situations.

How to fix violations

Example Violation

[TestCaseSource("MyTestSource")]
public void SampleTest(string stringValue)
{
    Assert.That(stringValue.Length, Is.EqualTo(3));
}

public static object[] MyTestSource()
{
    return new object[] {"One", "Two"};
}

Problem

In this case, we're referring to "MyTestSource" as a string directly. This is brittle; should the name of the property change, the test case source would become invalid, and we would not know this until executing tests.

Fix

The fix is to use the C# nameof operator, which produces a string but references the field name. This way, when refactoring and changing the name of your test source, it would also update the name within the nameof() operator.

The fix in action:

[TestCaseSource(nameof(MyTestSource))] // using nameof
public void SampleTest(string stringValue)
{
    Assert.That(stringValue.Length, Is.EqualTo(3));
}

public static object[] MyTestSource()
{
    return new object[] {"One", "Two"};
}

Configure severity

Via ruleset file.

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

Via #pragma directive.

#pragma warning disable NUnit1002 // TestCaseSource should use nameof operator to specify target.
Code violating the rule here
#pragma warning restore NUnit1002 // TestCaseSource should use nameof operator to specify target.

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

#pragma warning disable NUnit1002 // TestCaseSource should use nameof operator to specify target.

Via attribute [SuppressMessage].

[System.Diagnostics.CodeAnalysis.SuppressMessage("Structure", 
    "NUnit1002:TestCaseSource should use nameof operator to specify target.",
    Justification = "Reason...")]