<PackageReference Include="NUnit" Version="3.10.0" />

FalseConstraint

public class FalseConstraint : Constraint
FalseConstraint tests that the actual value is false
using System; namespace NUnit.Framework.Constraints { public class FalseConstraint : Constraint { public FalseConstraint() : base(Array.Empty<object>()) { Description = "False"; } public override ConstraintResult ApplyTo<TActual>(TActual actual) { return new ConstraintResult(this, actual, false.Equals((object)actual)); } } }