public void GetDetailsWhenNotNullDrugId() { config.Setup(p => p.searchDrugsByID(1)).Returns(new List <LocationWiseDrug> { new LocationWiseDrug() { } }); var result = TokenObj.searchDrugsByID(1); var rs = result as OkObjectResult; var rs1 = rs.Value as List <LocationWiseDrug>; Assert.That(rs1, Is.Not.Empty); // Assert.That(result,Is.InstanceOf<OkObjectResult>()); }