public void ExecuteOperations(string name) { var operationFactory = Substitute.For <IOperationFactory>(); var operation = new OperationExample1(); operationFactory.CreateOperation(name).Returns(operation); var test = new TestExample1(operationFactory); var operationActual = test.AddOperation(name); operationFactory.Received(1).CreateOperation(name); operationActual.Should().Be(operation); }