NUnit2017

Consider using Assert.That(expr, Is.Null) instead of ClassicAssert.IsNull(expr)

Topic	Value
Id	NUnit2017
Severity	Info
Enabled	True
Category	Assertion
Code	ClassicModelAssertUsageAnalyzer

Description

Consider using the constraint model, Assert.That(expr, Is.Null), instead of the classic model, ClassicAssert.IsNull(expr).

Motivation

The classic Assert model contains less flexibility than the constraint model, so this analyzer marks usages of ClassicAssert.IsNull from the classic Assert model.

[Test]
public void Test()
{
    object obj = null;
    ClassicAssert.IsNull(obj);
}

How to fix violations

The analyzer comes with a code fix that will replace ClassicAssert.IsNull(expression) with Assert.That(expression, Is.Null). So the code block above will be changed into.

[Test]
public void Test()
{
    object obj = null;
    Assert.That(obj, Is.Null);
}

Configure severity

Via ruleset file

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

Via .editorconfig file

# NUnit2017: Consider using Assert.That(expr, Is.Null) instead of ClassicAssert.IsNull(expr)
dotnet_diagnostic.NUnit2017.severity = chosenSeverity

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

Via #pragma directive

#pragma warning disable NUnit2017 // Consider using Assert.That(expr, Is.Null) instead of ClassicAssert.IsNull(expr)
Code violating the rule here
#pragma warning restore NUnit2017 // Consider using Assert.That(expr, Is.Null) instead of ClassicAssert.IsNull(expr)

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

#pragma warning disable NUnit2017 // Consider using Assert.That(expr, Is.Null) instead of ClassicAssert.IsNull(expr)

Via attribute [SuppressMessage]

[System.Diagnostics.CodeAnalysis.SuppressMessage("Assertion",
    "NUnit2017:Consider using Assert.That(expr, Is.Null) instead of ClassicAssert.IsNull(expr)",
    Justification = "Reason...")]