NUnit2049

Consider using Assert.That(...) instead of CollectionAssert(...)

Topic	Value
Id	NUnit2049
Severity	Warning
Enabled	True
Category	Assertion
Code	CollectionAssertUsageAnalyzer

Description

Consider using the constraint model, Assert.That(actual, {0}(expected)), instead of the classic model, CollectionAssert.{1}(expected, actual).

Motivation

The classic Assert model contains less flexibility than the constraint model and makes it easy to mix the order of the parameters, so this analyzer marks usages of all CollectionAssert methods from the classic Assert model.

[Test]
public void Test()
{
    CollectionAssert.AllItemsAreInstancesOfType(collection, expected);
    CollectionAssert.AllItemsAreNotNull(collection);
    CollectionAssert.AllItemsAreUnique(collection);
    CollectionAssert.AreEqual(expected, actual);
    CollectionAssert.AreEquivalent(expected, actual);
    CollectionAssert.AreNotEqual(expected, actual);
    CollectionAssert.AreNotEquivalent(expected, actual);
    CollectionAssert.Contains(collection, expected);
    CollectionAssert.DoesNotContain(collection, expected);
    CollectionAssert.IsNotSubsetOf(subset, superset);
    CollectionAssert.IsSubsetOf(subset, superset);
    CollectionAssert.IsNotSupersetOf(superset, subset);
    CollectionAssert.IsSupersetOf(superset, subset);
    CollectionAssert.IsEmpty(collection);
    CollectionAssert.IsNotEmpty(collection);
    CollectionAssert.IsOrdered(collection);
}

How to fix violations

The analyzer comes with a code fix that will replace StringAssert.<method>(expected, actual) with Assert.That(actual, <constraint>(expected)). So the code block above will be changed into.

[Test]
public void Test()
{
    Assert.That(collection, Is.All.InstanceOf(expected));
    Assert.That(collection, Is.All.Not.Null);
    Assert.That(collection, Is.Unique);
    Assert.That(actual, Is.EqualTo(expected).AsCollection);
    Assert.That(actual, Is.EquivalentTo(expected));
    Assert.That(actual, Is.Not.EqualTo(expected).AsCollection);
    Assert.That(actual, Is.Not.EquivalentTo(expected));
    Assert.That(collection, Has.Member(expected));
    Assert.That(collection, Has.No.Member(expected));
    Assert.That(subset, Is.Not.SubsetOf(superset));
    Assert.That(subset, Is.SubsetOf(superset));
    Assert.That(superset, Is.Not.SupersetOf(subset));
    Assert.That(superset, Is.SupersetOf(subset));
    Assert.That(collection, Is.Empty);
    Assert.That(collection, Is.Not.Empty);
    Assert.That(collection, Is.Ordered);
}

Configure severity

Via ruleset file

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

Via .editorconfig file

# NUnit2049: Consider using Assert.That(...) instead of CollectionAssert(...)
dotnet_diagnostic.NUnit2049.severity = chosenSeverity

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

Via #pragma directive

#pragma warning disable NUnit2049 // Consider using Assert.That(...) instead of CollectionAssert(...)
Code violating the rule here
#pragma warning restore NUnit2049 // Consider using Assert.That(...) instead of CollectionAssert(...)

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

#pragma warning disable NUnit2049 // Consider using Assert.That(...) instead of CollectionAssert(...)

Via attribute [SuppressMessage]

[System.Diagnostics.CodeAnalysis.SuppressMessage("Assertion",
    "NUnit2049:Consider using Assert.That(...) instead of CollectionAssert(...)",
    Justification = "Reason...")]