Develop Reference

Moq an object in a static class

I can't get Moq to mock an object that gets created in a static method.
Here is my moq and code
code:
public interface IConfigHelper
{
string GetConfiguration(string sectionName, string elementName);
}
public class ConfigHelper : IConfigHelper
{
public ConfigHelper() { }
public virtual string GetConfiguration(string sectionName, string elementName)
{
string retValue = String.Empty;
//Does things to get configuration and return a value
return retValue;
}
}
public class myRealClass
{
public myRealClass(){}
public string myworkingMethod()
{
var retValue = String.Empty;
retValue = utilSvc.GetConfigurationValue();
return retValue;
}
}
public static class utilSvc
{
public static string GetConfigurationValue()
{
ConfigHelper configUtil = new ConfigHelper(); //NOT BEING MOCKED
return configUtil.GetConfiguration("sectionName/sectionElement", "ClinicalSystem");
}
}
the Test using Moq
[TestFixture(TestName = "Tests")]
public class Tests
{
private Mock<IConfigHelper> configHelperMOCK;
[SetUp]
public void Setup()
{
configHelperMOCK = new Mock<IConfigHelper>();
}
[Test]
public void serviceIsBPManagementForValidSource()
{
//Arrange
string sectionName = "sectionName/sectionElement";
string clinicalElementName = "ClinicalSystem";
string clinicalElementValue = "Zedmed";
configHelperMOCK.Setup(s => s.GetConfiguration(sectionName, clinicalElementName)).Returns(clinicalElementValue);
//act
// the call to myRealClass
//assert
// test assertions
}
}
The issue that I am having is with this line:
ConfigHelper configUtil = new ConfigHelper(); //NOT BEING MOCKED
I cannot get the moq to Mock the object.
I do not want the code to read the config file. I wish to moq away this instance of ConfigHelper

You can't wrap the static class/method but you can redirect it
public static class UtilSvc
{
static UtilSvc()
{
CreatorFunc = () => new ConfigHelper();
}
public static Func<IConfigHelper> CreatorFunc { get; set; }
public static string GetConfigurationValue()
{
var configUtil = CreatorFunc();
return configUtil.GetConfiguration("sectionName/sectionElement",
"ClinicalSystem");
}
}
and then in the test
//...
private Mock<IConfigHelper> configHelperMOCK;
[SetUp]
public void Setup()
{
configHelperMOCK = new Mock<IConfigHelper>();
UtilService.CreatorFunc = () => configHelperMOCK.Object;
}
//...

You cannot mock static class. I would rather propose to inject that IConfigHelper into the myRealClass. That is the usual way how to decouple dependencies and use DI.
public class myRealClass
{
private IConfigHelper _configHelper;
public myRealClass(IConfigHelper configHelper)
{
_configHelper = configHelper;
}
public string myworkingMethod()
{
var retValue = String.Empty;
retValue = _configHelper.GetConfigurationValue();
return retValue;
}
}

Avoid coupling your code to static classes, which in most cases cause you code be to difficult to maintain and test.
Follow the Explicit Dependencies Principle
Methods and classes should explicitly require (typically through
method parameters or constructor parameters) any collaborating objects
they need in order to function correctly.
Give the article a read. It is short and very informative.
If you want to keep the static class then you wrap the static class behind an abstraction.
public interface IUtilSvc {
string GetConfigurationValue();
}
public class utilSvcWrapper : IUtilSvc {
public string GetConfigurationValue() {
return utilSvc.GetConfigurationValue(); //Calling static service
}
}
Or another option is that utlSvc does not have to be static if can be injected into dependent classes
public class utilSvc : IUtilScv {
private readonly IConfigHelper configUtil;
public utilSvc(IConfigHelper configHelper) {
configUtil = configHelper;
}
public string GetConfigurationValue() {
return configUtil.GetConfiguration("sectionName/sectionElement", "ClinicalSystem");
}
}
Inject the IUtilScv into the dependent class so that it is no longer dependent on static class.
public class myRealClass {
private readonly IUtilScv utilSvc;
//Explicit dependency inject via constructor
public myRealClass(IUtilScv utilSvc) {
this.utilSvc = utilSvc;
}
public string myworkingMethod() {
var retValue = utilSvc.GetConfiguration();
return retValue;
}
}
In that case you don't even need IConfigHelper when testing as it has also been abstracted away. And you only need to mock the dependencies needed for the test.
[TestFixture(TestName = "Tests")]
public class Tests {
private Mock<IUtilScv> utilScvMOCK;
[SetUp]
public void Setup() {
utilScvMOCK = new Mock<IUtilScv>();
}
[Test]
public void serviceIsBPManagementForValidSource() {
//Arrange
var expectedClinicalElementValue = "Zedmed";
utilScvMOCK
.Setup(s => s.GetConfiguration())
.Returns(expectedClinicalElementValue)
.Verifiable();
var sut = new myRealClass(utilScvMOCK.Object);
//Act
var actualClinicalElementValue = sut.myworkingMethod();
//Assert
configHelperMOCK.Verify();
Assert.AreEqual(expectedClinicalElementValue, actualClinicalElementValue);
}
}

Test Environment.Exit() in C#

Is there in C# some kind of equivalent of ExpectedSystemExit in Java? I have an exit in my code and would really like to be able to test it. The only thing I found in C# is a not really nice workaround.
Example Code
public void CheckRights()
{
if(!service.UserHasRights())
{
Environment.Exit(1);
}
}
Test Code
[TestMethod]
public void TestCheckRightsWithoutRights()
{
MyService service = ...
service.UserHasRights().Returns(false);
???
}
I am using the VS framework for testing (+ NSubstitute for mocking) but it is not a problem to switch to nunit or whatever for this test.

You should use dependency injection to supply to the class being tested an interface that provides an environmental exit.
For example:
public interface IEnvironment
{
void Exit(int code);
}
Let's also assume that you have an interface for calling UserHasRights():
public interface IRightsService
{
bool UserHasRights();
}
Now suppose your class to be tested looks like this:
public sealed class RightsChecker
{
readonly IRightsService service;
readonly IEnvironment environment;
public RightsChecker(IRightsService service, IEnvironment environment)
{
this.service = service;
this.environment = environment;
}
public void CheckRights()
{
if (!service.UserHasRights())
{
environment.Exit(1);
}
}
}
Now you can use a mocking framework to check that IEnvironment .Exit() is called under the right conditions. For example, using Moq it might look a bit like this:
[TestMethod]
public static void CheckRights_exits_program_when_user_has_no_rights()
{
var rightsService = new Mock<IRightsService>();
rightsService.Setup(foo => foo.UserHasRights()).Returns(false);
var enviromnent = new Mock<IEnvironment>();
var rightsChecker = new RightsChecker(rightsService.Object, enviromnent.Object);
rightsChecker.CheckRights();
enviromnent.Verify(foo => foo.Exit(1));
}
Ambient contexts and cross-cutting concerns
A method such as Environment.Exit() could be considered to be a cross-cutting concern, and you might well want to avoid passing around an interface for it because you can end up with an explosion of additional constructor parameters. (Note: The canonical example of a cross cutting concern is DateTime.Now.)
To address this issue, you can introduce an "Ambient context" - a pattern which allows you to use a static method while still retaining the ability to unit test calls to it. Of course, such things should be used sparingly and only for true cross-cutting concerns.
For example, you could introduce an ambient context for Environment like so:
public abstract class EnvironmentControl
{
public static EnvironmentControl Current
{
get
{
return _current;
}
set
{
if (value == null)
throw new ArgumentNullException(nameof(value));
_current = value;
}
}
public abstract void Exit(int value);
public static void ResetToDefault()
{
_current = DefaultEnvironmentControl.Instance;
}
static EnvironmentControl _current = DefaultEnvironmentControl.Instance;
}
public class DefaultEnvironmentControl : EnvironmentControl
{
public override void Exit(int value)
{
Environment.Exit(value);
}
public static DefaultEnvironmentControl Instance => _instance.Value;
static readonly Lazy<DefaultEnvironmentControl> _instance = new Lazy<DefaultEnvironmentControl>(() => new DefaultEnvironmentControl());
}
Normal code just calls EnvironmentControl.Current.Exit(). With this change, the IEnvironment parameter disappears from the RightsChecker class:
public sealed class RightsChecker
{
readonly IRightsService service;
public RightsChecker(IRightsService service)
{
this.service = service;
}
public void CheckRights()
{
if (!service.UserHasRights())
{
EnvironmentControl.Current.Exit(1);
}
}
}
But we still retain the ability to unit-test that it has been called:
public static void CheckRights_exits_program_when_user_has_no_rights()
{
var rightsService = new Mock<IRightsService>();
rightsService.Setup(foo => foo.UserHasRights()).Returns(false);
var enviromnent = new Mock<EnvironmentControl>();
EnvironmentControl.Current = enviromnent.Object;
try
{
var rightsChecker = new RightsChecker(rightsService.Object);
rightsChecker.CheckRights();
enviromnent.Verify(foo => foo.Exit(1));
}
finally
{
EnvironmentControl.ResetToDefault();
}
}
For more information about ambient contexts, see here.

I ended up creating a new method which I can then mock in my tests.
Code
public void CheckRights()
{
if(!service.UserHasRights())
{
Environment.Exit(1);
}
}
internal virtual void Exit()
{
Environment.Exit(1);
}
Unit test
[TestMethod]
public void TestCheckRightsWithoutRights()
{
MyService service = ...
service.When(svc => svc.Exit()).DoNotCallBase();
...
service.CheckRights();
service.Received(1).Exit();
}

If your goal is to avoid extra classes/interfaces just to support tests, how do you feel about Environment.Exit action via Property Injection?
class RightsChecker
{
public Action AccessDeniedAction { get; set; }
public RightsChecker(...)
{
...
AccessDeniedAction = () => Environment.Exit();
}
}
[Test]
public TestCheckRightsWithoutRights()
{
...
bool wasAccessDeniedActionExecuted = false;
rightsChecker.AccessDeniedAction = () => { wasAccessDeniedActionExecuted = true; }
...
Assert.That(wasAccessDeniedActionExecuted , Is.True);
}

verifying setup on a passed in mocked object

I am testing my class
public class myclass
{
private IAwesome awesomeObject;
public myclass(IAwesome awesomeObject)
{
this.awesomeObject = awesomeObject;
}
public void MethodUnderTest()
{
this.awesomeObject.RunSomething(); //I want to verify that RunSomething was called
}
}
The way I am doing this is:
//Arrange
var mockAwesome = new Mock<IAwesome>();
mockAwesome.Setup(x=>x.RunSomething()).Returns ... Verify()...;
//Act
var sut = new myclass(mockAwesome.object);
sut.MethodUnderTest();
//Assert
mockAwesome.Verify();
The exception I am getting is:
System.NotSupportedException : Expression references a method that
does not belong to the mocked object: x => x.RunSomething
Is it not possible to test that a specific method was executed on a mocked object that I passed into a class, that is now part of a private member of that class?

Modify set up line to mockAwesome.Setup(x=>x.RunSomething()).Verifiable() and it should work for the example you provided.
[TestClass]
public class MoqVerificationTest {
[TestMethod]
public void Moq_Should_Verify_Setup() {
//Arrange
var mockAwesome = new Mock<IAwesome>();
mockAwesome.Setup(x => x.RunSomething()).Verifiable();
//Act
var sut = new myclass(mockAwesome.Object);
sut.MethodUnderTest();
//Assert
mockAwesome.Verify();
}
public interface IAwesome {
void RunSomething();
}
public class myclass {
private IAwesome awesomeObject;
public myclass(IAwesome awesomeObject) {
this.awesomeObject = awesomeObject;
}
public void MethodUnderTest() {
this.awesomeObject.RunSomething(); //I want to verify that RunSomething was called
}
}
}
To confirm, comment out this.awesomeObject.RunSomething() in your sample class and run the test again. It will fail because you setup the RunSomething as Verifiable() and it was not used.

When testing, works perfectly fine for me...
Try this approach see if anything different results...
void Main()
{
IAwesome awesome = Mock.Of<IAwesome>();
Mock<IAwesome> mock = Mock.Get(awesome);
mock.Setup(m => m.RunSomething());
MyClass myClass = new MyClass(awesome);
myClass.MethodUnderTest();
mock.Verify(m => m.RunSomething(), Times.Once);
}
public interface IAwesome
{
void RunSomething();
}
public class MyClass
{
private IAwesome awesomeObject;
public myclass(IAwesome awesomeObject)
{
this.awesomeObject = awesomeObject;
}
public void MethodUnderTest()
{
this.awesomeObject.RunSomething();
}
}

How to make InteractionRequest in ViewModel testable?

I'm using PRISM and autofac for WPF on .Net 4.0 and I would like to develop an testable ViewModels. For testing we using nUnit and moq for mocking.
So I have a class:
public class BackupViewModel : InteractionRequestNotificationObject
{
private readonly DelegateCommand backupCommand;
private readonly IBackupCommandService commandService;
private readonly InteractionRequest<SaveBrowserDialogViewModel> saveDialogRequest = new InteractionRequest<SaveBrowserDialogViewModel>();
public BackupViewModel(IBackupCommandService commandService, ISaveBrowserDialogViewModel saveBrowserDialog)
{
if(commandService == null)
throw new ArgumentNullException("commandService");
if(saveBrowserDialog == null)
throw new ArgumentNullException("saveBrowserDialog");
this.commandService = commandService;
this.saveBrowserDialog = saveBrowserDialog;
this.backupCommand = new DelegateCommand(Backup);
}
private void Backup()
{
saveBrowserDialog.Filters = "Zip archive (*.zip)|*.zip";
saveDialogRequest.Raise((SaveBrowserDialogViewModel)saveBrowserDialog);
if (saveBrowserDialog.Confirmed)
{
commandService.BackupDatabase(saveBrowserDialog.Path);
}
}
}
And I have write unit test:
[TestFixture]
public class BackupViewModelTests
{
private BackupViewModel sut;
private Mock<IBackupCommandService> backupCommandServiceMock;
private Mock<ISaveBrowserDialogViewModel> saveDialogMock;
[SetUp]
public void Setup()
{
backupCommandServiceMock = new Mock<IBackupCommandService>();
saveDialogMock = new Mock<ISaveBrowserDialogViewModel>();
sut = new BackupViewModel(backupCommandServiceMock.Object, saveDialogMock.Object);
}
[Test]
public void BackupViewModelShouldCallBackupFromCommandService()
{
saveDialogMock.Setup(x => x.Confirmed).Returns(true);
sut.BackupCommand.Execute(null);
backupCommandServiceMock.Verify(x => x.BackupDatabase(It.IsAny<string>()),Times.Once());
}
}
Now I have yet no idea how to mock saveDialogRequest.Raise(..) so what it can work with an mocking object, not with a real SaveBrowserDialogViewModel.

The simplest answer would be to insert a 'seem' (see Working Effectively with Legacy Code by Michael Feathers) around the static class InteractionRequest<SaveBrowserDialogViewModel>.
This would mean pushing this behind an inteface (and implementation) and then registering this interface and implementation with AutoFac and then pass an instance to the ViewModel class as constructor argument. This would then allow you to mock out the interface in your test.
Something like this:
public interface IInteractionRequestWrapper<T>
{
void Request(T instance);
}
public class InteractionRequestWrapper<T> : IInteractionRequestWrapper<T>
{
private InteractionRequest<T> _saveDialogRequest;
public InteractionRequestWrapper()
{
_saveDialogRequest = new InteractionRequest<T>();
}
public void Request(T instance)
{
_saveDialogRequest.Request(instance);
}
}

Testing the scope of a type with structureMap

How do I test the scope of a registered type with structureMap?
For instance I have a registry:
public class DataRegistry : Registry
{
public DataRegistry()
{
ForRequestedType<ISessionManager>().TheDefaultIsConcreteType<SessionManager>().CacheBy(StructureMap.Attributes.InstanceScope.Singleton);
ForRequestedType<ISessionRequest>().TheDefaultIsConcreteType<SessionRequest>().CacheBy(StructureMap.Attributes.InstanceScope.HttpContext);
}
}
And I want to test that ISessionRequest instance scope is HttpContext. So I have a test:
[Test]
public void Container_AlwaysHas_OneSessionRequestPerHTTPContext()
{
//Setup
//Act
ObjectFactory.Configure(r => r.AddRegistry<DataRegistry>());
//Test
}
But I don't know to test the scope of the type once it's registered?

I believe you wish to write a test proving that the lifecycle of a registered plugin has the desired lifecycle.
You can inspect the model of the container. Here is one of the tests you wish to write.
[TestFixture]
public class container_registration
{
[Test]
public void session_request_should_be_scopped_per_httpcontext()
{
var container = new Container(new DataRegistry());
var plugin = container.Model.PluginTypes.First(p => p.PluginType.UnderlyingSystemType == typeof(ISessionRequest));
plugin.Lifecycle.ShouldBeOfType(typeof(HttpContextLifecycle));
}
}

[TestFixture]
public class WhenRegisteringItemsInTheIoc
{
[SetUp]
public void Setup()
{
Given_A_Ioc_Container();
When_Registering_Items_In_The_Ioc();
}
private Container _container;
private void Given_A_Ioc_Container()
{
_container = new Container();
}
public void When_Registering_Items_In_The_Ioc()
{
_container.Configure(registry => registry.For<IContext>().HybridHttpOrThreadLocalScoped().Use<Context>());
}
[Test]
public void Then_Should_Have_A_LifeTime_Of_Hybrid_Http_Or_Thread_Local_Scoped()
{
IPluginTypeConfiguration plugin =
_container.Model.PluginTypes.First(p => p.PluginType.UnderlyingSystemType == typeof (IContext));
Assert.That(plugin.Lifecycle, Is.EqualTo("Hybrid"));
}
}
In case anyone revisits this in the future, the above is a test we are using to cover this scenario. "plugin.Lifecycle" returns a string relating to the scope, which in this case is "Hybrid". If no scope is defined "Transient" is returned.