public async Task CreateVirtualMachineAsync_ExpectedResult() { CreateVirtualMachineRequest req = new CreateVirtualMachineRequest() { Template = "testtemplate" }; IUKFastECloudClient client = Substitute.For <IUKFastECloudClient>(); client.PostAsync <VirtualMachine>("/ecloud/v1/vms", req).Returns(new VirtualMachine() { ID = 123 }); var ops = new VirtualMachineOperations <VirtualMachine>(client); var vmID = await ops.CreateVirtualMachineAsync(req); Assert.AreEqual(123, vmID); }