I'm trying to test a private method on a mocked object. Please, calm down, I know you're getting your pitchforks out.
I'm well aware everything about to say can be answered by yelling REFACTOR at me. I just need a straight answer. Someone look me in the eyes and tell me this can't be done. It's an ungoogleable problem, so I just need to hear it.
Here's what I'm dealing with.
public class SecretManager
{
protected virtual string AwfulString { get { return "AWFUL, AWFUL THING"; }
public SecretManager()
{
//do something awful that should be done using injection
}
private string RevealSecretMessage()
{
return "don't forget to drink your ovaltine";
}
}
Here's me trying to test it.
var mgr = new Mock<SecretManager>();
mgr.Protected().SetupGet<string>("AwfulThing").Returns("");
var privateObj = new PrivateObject(mgr.Object);
string secretmsg = privateObj.Invoke("RevealSecretMessage");
Assert.IsTrue(secretmsg.Contains("ovaltine"));
and the exception:
System.MissingMethodException: Method 'Castle.Proxies.SecretManagerProxy.RevealSecretMessage' not found
Is what I'm trying to do, mad as it is, possible? Or is this simply too much hubris for a unit test to bear?
You're trying to call a method on the proxy that Castle created. The proxy won't have access to the private method on the class that it inherits from because, well, the method is private. Remember that Castle.Proxies.SecretManagerProxy is actually a subclass of SecretManager.
Do you really need a mock of SecretManager? I realize your code is a slimmed down abstract of the real code, but it seems the only thing you're doing with the mock is setting up a return for a property that isn't used by the method you're trying to test anyway.
var privateObj = new PrivateObject(mgr.Object, new PrivateType(typeof(SecretManager)));
string secretmsg = privateObj.Invoke("RevealSecretMessage");
It will work by specifying PrivateType for the PrivateObject.
Your code should be following for what you are trying to test. You don't need to mock the SecretManager and SetGet "AwfulThing" as you are not using it.
var privateObj = new PrivateObject(new SecretManager());
string secretmsg = (string)privateObj.Invoke("RevealSecretMessage", new object[] { });
Assert.IsTrue(secretmsg.Contains("ovaltine"));
But ideally you shouldn't be testing Private methods. See below article for the explanation:
http://lassekoskela.com/thoughts/24/test-everything-but-not-private-methods/
Related
I'm trying to setup unit testing for my API controllers. I'm using the mediatr pattern and FakeIteasy.
I have the following code.
public class ChannelGroupChannelsControllerTests
{
private readonly ChannelGroupChannelsController _controller;
private readonly IMediator _mediator;
public ChannelGroupChannelsControllerTests()
{
var service = A.Fake<IReadChannelGroupChannel>();
var mapper = A.Fake<IMapper>();
var channelGroupChannel = new ChannelGroupChannel
{
Id = 1,
ChannelGroupId = 1,
ChannelId = 1,
Channel = new Channel { Name = "Channel Name" }
};
_mediator = A.Fake<IMediator>();
_controller = new ChannelGroupChannelsController(_mediator, mapper);
A.CallTo(() => _mediator.Send(A<GetChannelGroupChannelById>._, A<CancellationToken>._)).Returns(channelGroupChannel);
}
[Fact]
public async Task ChannelGroupChannelsController_ById()
{
var result = await _controller.ById(1);
(result.Result as StatusCodeResult)?.StatusCode.Should().Be((int)HttpStatusCode.OK);
result.Value.Should().BeOfType<ChannelGroupChannelVM>();
}
}
Now the problem is that I keep getting NULL as a value.
I think the issue might be that GetChannelGroupChannelById has a constructor that expects the ID. But I'm not sure...
Does anybody know what could be wrong? I'm pretty new with the mocking stuff.
Kind regards
I'm not familiar with mediatr, so may be off base here, and it would be much easier to answer this question if we saw what your controller was doing. If you're able, please supply the code, as without that insight, I'm left to guess a little, but I'll try.
If GetChannelGroupChannelById's constructor expects an ID (an int?), FakeItEasy will provide an ID when it makes the Fake version. If it's an int, FakeItEasy will provide a 0, unless you've done some very fancy configuration you've not shown us. If that's supposed to line up with some other value in your code and doesn't, it may cause your problem.
Otherwise, I see you have a Fake IMapper, that is never configured, but is passed into the controller. I'm guessing this is supposed to translate some values. An unconfigured Fake will return a dummy value (or default if no dummy value can be made). It's possible that this unconfigured mapper is interrupting your flow.
(I also see that service in the test class constructor is unused. I would remove it or use it. It may not be part of your problem, but it's at least distracting.)
Coming from using Moq, I'm used to being able to Setup mocks as Verifiable. As you know, this is handy when you want to ensure your code under test actually called a method on a dependency.
e.g. in Moq:
// Set up the Moq mock to be verified
mockDependency.Setup(x => x.SomethingImportantToKnow()).Verifiable("Darn, this did not get called.");
target = new ClassUnderTest(mockDependency);
// Act on the object under test, using the mock dependency
target.DoThingsThatShouldUseTheDependency();
// Verify the mock was called.
mockDependency.Verify();
I've been using VS2012's "Fakes Framework" (for lack of knowing a better name for it), which is quite slick and I'm starting to prefer it to Moq, as it seems a bit more expressive and makes Shims easy. However, I can't figure out how to reproduce behavior similar to Moq's Verifiable/Verify implementation. I found the InstanceObserver property on the Stubs, which sounds like it might be what I want, but there's no documentation as of 9/4/12, and I'm not clear how to use it, if it's even the right thing.
Can anyone point me in the right direction on doing something like Moq Verifiable/Verify with VS2012's Fakes?
-- 9/5/12 Edit --
I realized a solution to the problem, but I'd still like to know if there's a built-in way to do it with VS2012 Fakes. I'll leave this open a little while for someone to claim if they can. Here's the basic idea I have (apologies if it doesn't compile).
[TestClass]
public class ClassUnderTestTests
{
private class Arrangements
{
public ClassUnderTest Target;
public bool SomethingImportantToKnowWasCalled = false; // Create a flag!
public Arrangements()
{
var mockDependency = new Fakes.StubIDependency // Fakes sweetness.
{
SomethingImportantToKnow = () => { SomethingImportantToKnowWasCalled = true; } // Set the flag!
}
Target = new ClassUnderTest(mockDependency);
}
}
[TestMethod]
public void DoThingThatShouldUseTheDependency_Condition_Result()
{
// arrange
var arrangements = new Arrangements();
// act
arrangements.Target.DoThingThatShouldUseTheDependency();
// assert
Assert.IsTrue(arrangements.SomethingImportantToKnowWasCalled); // Voila!
}
}
-- 9/5/12 End edit --
Since I've heard no better solutions, I'm calling the edits from 9/5/12 the best approach for now.
EDIT
Found the magic article that describes best practices. http://www.peterprovost.org/blog/2012/11/29/visual-studio-2012-fakes-part-3/
Although it might make sense in complex scenarios, you don't have to use a separate (Arrangements) class to store information about methods being called. Here is a simpler way of verifying that a method was called with Fakes, which stores the information in a local variable instead of a field of a separate class. Like your example it implies that ClassUnderTest calls a method of the IDependency interface.
[TestMethod]
public void DoThingThatShouldUseTheDependency_Condition_Result()
{
// arrange
bool dependencyCalled = false;
var dependency = new Fakes.StubIDependency()
{
DoStuff = () => dependencyCalled = true;
}
var target = new ClassUnderTest(dependency);
// act
target.DoStuff();
// assert
Assert.IsTrue(dependencyCalled);
}
I'm trying to work out why some of my test cases (using RhinoMocks 3.6 Build 20) aren't working, and I've narrowed the issue down to the following minimal unit test:
public interface ITest
{
string Something { get; }
}
[Test]
public void TestStub()
{
var mockery = new MockRepository();
var testItem = mockery.Stub<ITest>();
testItem.Stub(x => x.Something).Return("Hello");
Assert.AreEqual("Hello", testItem.Something);
}
This fails with the message:
Expected: "Hello" But was: null
Any ideas what I'm doing wrong here? I've found a few examples on SO and the Rhino Wiki on how to stub read-only properties, and as far as I can tell, this should work fine.
Cheers in advance.
EDIT: Based on sll's advice below, I tried replacing
testItem.Stub(x => x.Something).Return("Hello");
with
testItem.Expect(x => x.Something).Return("Hello");
and the test still fails in the same manner.
Edit 2: I've got this working by adding the line
mockery.ReplayAll();
before the Assert - but I thought this was no longer required (from the wiki: "Mocks/stubs returned from MockRepository.GenerateMock() and MockRepository.GenerateStub() are returned in replay mode, and do not require explicit move to replay mode.")
Try out generating Mock instead:
var testItem = MockRepository.GenerateMock<ITest>();
testItem.Expect(x => x.Something).Return("Hello");
Assert.AreEqual("Hello", testItem.Something);
Als make sure you shared entire test method, perhaps you ignored some lines of code?
Try out usign Repeat.Any() perhaps proeprty accessed before you are doing expectation.
testItem.Expect(x => x.Something).Return("Hello").Repeat.Any();
On example page Stub() used for methods, and suggested using Mock's Expect() for properties:
Using Expect() to set up properties
The Expect() extention method can be used to set up expectations and
return values for properties.
Got it:
From the RhinoMocks 3.6 Blog Post comments:
09/03/2009 05:34 PM by
Kurt Harriger
FYI,
I had a few dozen tests fail after upgrading to v 3.6 from code like this:
var mocks = new MockRepository();
var something = mocks.Stub
something.Stub(x=>x.DoSomething() ).Return(true);
something.DoSomething();
The root cause of the problem appears that mock.Stub/Mock/etc no longer returns the mock in replay mode. To fix replaced mock.Stub with MockRepository.GenerateStub.
Ayende Rahien
09/03/2009 06:50 PM by
Ayende Rahien
Kurt,
That is actually expected, that should have never worked
So, by changing the test to:
[Test]
public void TestStub()
{
var testItem = MockRepository.GenerateStub<ITest>();
testItem.Stub(x => x.Something).Return("Hello");
Assert.AreEqual("Hello", testItem.Something);
}
this now works.
Cheers
You are just setting the value so you would expect to do this like this:
public interface ITest
{
string Something { get; }
}
[Test]
public void TestStub()
{
var mockery = new MockRepository();
var testItem = mockery.Stub<ITest>();
testItem.Something = "Hello";
Assert.AreEqual("Hello", testItem.Something);
}
No need to Stub with Func.
I'm trying to become more familiar with the Rhinomocks framework, and I'm trying to understand the Expect methods of rhinomocks.
Here's a unit test I have written:
[TestMethod]
public void Create_ValidModelData_CreatesNewEventObjectWithGivenSlugId()
{
//Arrange
var eventList = new List<Event>() { new Event() { Slug = "test-user" } };
_stubbedEventRepository.Stub(x => x.GetEvents())
.Return(eventList);
_stubbedEventRepository
.Expect(x => x.SaveEvent(eventList.SingleOrDefault()))
.Repeat
.Once();
var controller = new EventController(_stubbedEventRepository);
EventViewModel model = new EventViewModel();
//Act
//controller.Create(model); COMMENTED OUT
//Assert
_stubbedEventRepository.VerifyAllExpectations();
}
I thought I understood this code to only pass if the SaveEvent(...) method get's called exactly once. However, with controller.Create(model) commented out, the test still passes. Inside controller.Create(model) is where the SaveEvent() method gets called.
I tried the following:
_stubbedEventRepository
.Expect(x => x.SaveEvent(eventList.SingleOrDefault()));
But it still passes every time, so what am I doing incorrectly stack overflow? The sources I have looked at online haven't been able to help me. Why is VerifyAllExpectations() yielding a successful unit test?
Thank you!
Here's the body of the controller constructor:
public EventController(IEventRepository eventRepository)
{
_eventRepository = eventRepository;
}
edit:
// member variables
private IEventRepository _stubbedEventRepository;
[TestInitialize]
public void SetupTests()
{
_stubbedEventRepository = MockRepository.GenerateStub<IEventRepository>();
}
If you want to verify the behavior of the code under test, you will use a mock with the appropriate expectation, and verify that. If you want just to pass a value that may need to act in a certain way, but isn't the focus of this test, you will use a stub.
Long story short
Say I have the following code:
// a class like this
class FirstObject {
public Object OneProperty {
get;
set;
}
// (other properties)
public Object OneMethod() {
// logic
}
}
// and another class with properties and methods names
// which are similar or exact the same if needed
class SecondObject {
public Object OneProperty {
get;
set;
}
// (other properties)
public Object OneMethod(String canHaveParameters) {
// logic
}
}
// the consuming code would be something like this
public static void main(String[] args) {
FirstObject myObject=new FirstObject();
// Use its properties and methods
Console.WriteLine("FirstObject.OneProperty value: "+myObject.OneProperty);
Console.WriteLine("FirstObject.OneMethod returned value: "+myObject.OneMethod());
// Now, for some reason, continue to use the
// same object but with another type
// -----> CHANGE FirstObject to SecondObject HERE <-----
// Continue to use properties and methods but
// this time calls were being made to SecondObject properties and Methods
Console.WriteLine("SecondObject.OneProperty value: "+myObject.OneProperty);
Console.WriteLine("SecondObject.OneMethod returned value: "+myObject.OneMethod(oneParameter));
}
Is it possible to change FirstObject type to SecondObject and continue to use it's properties and methods?
I've total control over FirstObject, but SecondObject is sealed and totally out of my scope!
May I achieve this through reflection? How? What do you think of the work that it might take to do it? Obviously both class can be a LOT more complex than the example above.
Both class can have templates like FirstObject<T> and SecondObject<T> which is intimidating me to use reflection for such a task!
Problem in reality
I've tried to state my problem the easier way for the sake of simplicity and to try to extract some knowledge to solve it but, by looking to the answers, it seems obvious to me that, to help me, you need to understand my real problem because changing object type is only the tip of the iceberg.
I'm developing a Workflow Definition API. The main objective is to have a API able to be reusable on top of any engine I might want to use(CLR through WF4, NetBPM, etc.).
By now I'm writing the middle layer to translate that API to WF4 to run workflows through the CLR.
What I've already accomplished
The API concept, at this stage, is somehow similar to WF4 with ActivityStates with In/Out Arguments and Data(Variables) running through the ActivityStates using their arguments.
Very simplified API in pseudo-code:
class Argument {
object Value;
}
class Data {
String Name;
Type ValueType;
object Value;
}
class ActivityState {
String DescriptiveName;
}
class MyIf: ActivityState {
InArgument Condition;
ActivityState Then;
ActivityState Else;
}
class MySequence: ActivityState {
Collection<Data> Data;
Collection<ActivityState> Activities;
}
My initial approach to translate this to WF4 was too run through the ActivitiesStates graph and do a somehow direct assignment of properties, using reflection where needed.
Again simplified pseudo-code, something like:
new Activities.If() {
DisplayName=myIf.DescriptiveName,
Condition=TranslateArgumentTo_WF4_Argument(myIf.Condition),
Then=TranslateActivityStateTo_WF4_Activity(myIf.Then),
Else=TranslateActivityStateTo_WF4_Activity(myIf.Else)
}
new Activities.Sequence() {
DisplayName=mySequence.DescriptiveName,
Variables=TranslateDataTo_WF4_Variables(mySequence.Variables),
Activities=TranslateActivitiesStatesTo_WF4_Activities(mySequence.Activities)
}
At the end of the translation I would have an executable System.Activities.Activity object. I've already accomplished this easily.
The big issue
A big issue with this approach appeared when I began the Data object to System.Activities.Variable translation. The problem is WF4 separates the workflow execution from the context. Because of that both Arguments and Variables are LocationReferences that must be accessed through var.Get(context) function for the engine to know where they are at runtime.
Something like this is easily accomplished using WF4:
Variable<string> var1=new Variable<string>("varname1", "string value");
Variable<int> var2=new Variable<int>("varname2", 123);
return new Sequence {
Name="Sequence Activity",
Variables=new Collection<Variable> { var1, var2 },
Activities=new Collection<Activity>(){
new Write() {
Name="WriteActivity1",
Text=new InArgument<string>(
context =>
String.Format("String value: {0}", var1.Get(context)))
},
new Write() {
//Name = "WriteActivity2",
Text=new InArgument<string>(
context =>
String.Format("Int value: {0}", var2.Get(context)))
}
}
};
but if I want to represent the same workflow through my API:
Data<string> var1=new Data<string>("varname1", "string value");
Data<int> var2=new Data<int>("varname2", 123);
return new Sequence() {
DescriptiveName="Sequence Activity",
Data=new Collection<Data> { var1, var2 },
Activities=new Collection<ActivityState>(){
new Write() {
DescriptiveName="WriteActivity1",
Text="String value: "+var1 // <-- BIG PROBLEM !!
},
new Write() {
DescriptiveName="WriteActivity2",
Text="Int value: "+Convert.ToInt32(var2) // ANOTHER BIG PROBLEM !!
}
}
};
I end up with a BIG PROBLEM when using Data objects as Variables. I really don't know how to allow the developer, using my API, to use Data objects wherever who wants(just like in WF4) and later translate that Data to System.Activities.Variable.
Solutions come to mind
If you now understand my problem, the FirstObject and SecondObject are the Data and System.Activities.Variable respectively. Like I said translate Data to Variable is just the tip of the iceberg because I might use Data.Get() in my code and don't know how to translate it to Variable.Get(context) while doing the translation.
Solutions that I've tried or thought of:
Solution 1
Instead of a direct translation of properties I would develop NativeActivites for each flow-control activity(If, Sequence, Switch, ...) and make use of CacheMetadata() function to specify Arguments and Variables. The problem remains because they are both accessed through var.Get(context).
Solution 2
Give my Data class its own Get() function. It would be only an abstract method, without logic inside that it would, somehow, translate to Get() function of System.Activities.Variable. Is this even possible using C#? Guess not! Another problem is that a Variable.Get() has one parameter.
Solution 3
The worst solution that I thought of was CIL-manipulation. Try to replace the code where Data/Argument is used with Variable/Argument code. This smells like a nightmare to me. I know next to nothing about System.reflection.Emit and even if I learn it my guess is that it would take ages ... and might not even be possible to do it.
Sorry if I ended up introducing a bigger problem but I'm really stuck here and desperately needing a tip/path to go on.
This is called "duck typing" (if it looks like a duck and quacks like a duck you can call methods on it as though it really were a duck). Declare myObject as dynamic instead of as a specific type and you should then be good to go.
EDIT: to be clear, this requires .NET 4.0
dynamic myObject = new FirstObject();
// do stuff
myObject = new SecondObject();
// do stuff again
Reflection isn't necessarily the right task for this. If SecondObject is out of your control, your best option is likely to just make an extension method that instantiates a new copy of it and copies across the data, property by property.
You could use reflection for the copying process, and work that way, but that is really a separate issue.