public void Service1_GetDataTest() { // Arrange this._service.Setup(s => s.GetData(It.IsAny<int>())).Returns("test"); Business.WCF.Service1 service = new Business.WCF.Service1(_service.Object); // Act var result = service.GetData(It.IsAny<int>()); // Assert Assert.IsInstanceOfType(result, typeof(string)); }