NUnit.Framework.Contains public abstract class Contains Helper class with properties and methods that supply a number of constraints used in Asserts. Documentation Code namespace NUnit.Framework { public abstract class Contains { public static SomeItemsConstraint Item(object expected); public static DictionaryContainsKeyConstraint Key(object expected); public static DictionaryContainsValueConstraint Value(object expected); public static SubstringConstraint Substring(string expected); protected Contains(); } }