NUnit2023

Invalid NullConstraint usage

Description

NullConstraint is allowed only for reference types or nullable value types.

Motivation

Non-nullable value types cannot have null value, therefore Is.Null assertions will always fail (or will always pass for Is.Not.Null).

How to fix violations

Use suitable constraint.

Configure severity

Via ruleset file

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

Via .editorconfig file

# NUnit2023: Invalid NullConstraint usage
dotnet_diagnostic.NUnit2023.severity = chosenSeverity

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

Via #pragma directive

#pragma warning disable NUnit2023 // Invalid NullConstraint usage
Code violating the rule here
#pragma warning restore NUnit2023 // Invalid NullConstraint usage

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

#pragma warning disable NUnit2023 // Invalid NullConstraint usage

Via attribute [SuppressMessage]

[System.Diagnostics.CodeAnalysis.SuppressMessage("Assertion",
    "NUnit2023:Invalid NullConstraint usage",
    Justification = "Reason...")]