<PackageReference Include="NUnit" Version="4.2.1" />

Does

public abstract class Does
Helper class with properties and methods that supply a number of constraints used in Asserts.
using NUnit.Framework.Constraints; using System.Diagnostics.CodeAnalysis; using System.Runtime.CompilerServices; using System.Text.RegularExpressions; namespace NUnit.Framework { [System.Runtime.CompilerServices.NullableContext(1)] [System.Runtime.CompilerServices.Nullable(0)] public abstract class Does { public static ConstraintExpression Not => new ConstraintExpression().Not; public static FileOrDirectoryExistsConstraint Exist => new FileOrDirectoryExistsConstraint(); public static SomeItemsConstraint Contain([System.Runtime.CompilerServices.Nullable(2)] object expected) { return new SomeItemsConstraint(new EqualConstraint(expected)); } public static ContainsConstraint Contain([System.Runtime.CompilerServices.Nullable(2)] string expected) { return new ContainsConstraint(expected); } public static DictionaryContainsKeyConstraint ContainKey(object expected) { return Contains.Key(expected); } public static DictionaryContainsValueConstraint ContainValue([System.Runtime.CompilerServices.Nullable(2)] object expected) { return Contains.Value(expected); } public static StartsWithConstraint StartWith(string expected) { return new StartsWithConstraint(expected); } public static EndsWithConstraint EndWith(string expected) { return new EndsWithConstraint(expected); } public static RegexConstraint Match([StringSyntax("Regex")] string pattern) { return new RegexConstraint(pattern); } public static RegexConstraint Match(Regex regex) { return new RegexConstraint(regex); } } }