How can I test that a particular method was called with the right parameters as a result of a test? I am using NUnit.
The method doesn't return anything. it just writes on a file. I am using a mock object for System.IO.File. So I want to test that the function was called or not.
More context is needed. So I'll put one here adding Moq to the mix:
pubilc class Calc {
public int DoubleIt(string a) {
return ToInt(a)*2;
}
public virtual int ToInt(string s) {
return int.Parse(s);
}
}
// The test:
var mock = new Mock<Calc>();
string parameterPassed = null;
mock.Setup(c => x.ToInt(It.Is.Any<int>())).Returns(3).Callback(s => parameterPassed = s);
mock.Object.DoubleIt("3");
Assert.AreEqual("3", parameterPassed);
You have to use some mocking framework, such as Typemock or Rhino Mocks, or NMocks2.
NUnit also has a Nunit.Mock, but it is not well-known.
The syntax for moq can be found here:
var mock = new Mock<ILoveThisFramework>();
// WOW! No record/reply weirdness?! :)
mock.Setup(framework => framework.DownloadExists("2.0.0.0"))
.Returns(true)
.AtMostOnce();
// Hand mock.Object as a collaborator and exercise it,
// like calling methods on it...
ILoveThisFramework lovable = mock.Object;
bool download = lovable.DownloadExists("2.0.0.0");
// Verify that the given method was indeed called with the expected value
mock.Verify(framework => framework.DownloadExists("2.0.0.0"));
Also, note that you can only mock interface, so if your object from System.IO.File doesn't have an interface, then probably you can't do. You have to wrap your call to System.IO.File inside your own custom class for the job.
By using a mock for an interface.
Say you have your class ImplClass which uses the interface Finder and you want to make sure the Search function gets called with the argument "hello";
so we have:
public interface Finder
{
public string Search(string arg);
}
and
public class ImplClass
{
public ImplClass(Finder finder)
{
...
}
public void doStuff();
}
Then you can write a mock for your test code
private class FinderMock : Finder
{
public int numTimesCalled = 0;
string expected;
public FinderMock(string expected)
{
this.expected = expected;
}
public string Search(string arg)
{
numTimesCalled++;
Assert.AreEqual(expected, arg);
}
}
then the test code:
FinderMock mock = new FinderMock("hello");
ImplClass impl = new ImplClass(mock);
impl.doStuff();
Assert.AreEqual(1, mock.numTimesCalled);
In Rhino Mocks where is a method called AssertWasCalled
Here is a way to use it
var mailDeliveryManager = MockRepository.GenerateMock<IMailDeliveryManager>();
var mailHandler = new PlannedSending.Business.Handlers.MailHandler(mailDeliveryManager);
mailHandler.NotifyPrinting(User, Info);
mailDeliveryManager.AssertWasCalled(x => x.SendMailMessage(null, null, null), o => o.IgnoreArguments());
Related
I was trying to Mock some some functionality of my Services. The code goes like this.
public interface IObj {
public bool anotherMethod(string input, out string responseString);
}
public class SomeClass {
public bool SomeMethod(string input, out IObj outputObj) {
// some logic
if (logic is correct) {
outputObj = // object of IObj
return true;
}
outputObj = null;
return false;
}
}
public class Service {
public void executingMethod(){
if (this.someClassObj.SomeMethod(this.inputString, out outputObj) {
if (outputObj.anotherMethod(this.anotherInputString, out responseString)
{
// some business logic
}
}
}
}
Now i want to Mock the method executingMethod behaviour vai UnitTest using Moq and xUnit.
But while mocking I am getting issue with out parameter. In this way I am trying to mock the behaviour.
[Fact]
public void MockingMethod(){
// Arrange
Mock<SomeClass> mockSomeClass = new Mock<SomeClass>();
Mock<IObj> mockIObj = new Mock<IObj>();
string mockedResponse = "someResponse";
// here i am getting the issue, as out is expecting actual object not mocked object.
mockSomeClass.Setup(s => s.SomeMethod(It.IsAny<string>(), out mockIObj).Returns(true);
mockIObj.Setup(s => s.anotherMethod(It.IsAny<string(), out mockedResponse).Returns(true);
}
Any help will be much appreciated. TIA.
I tried to use as suggested by #Roman as well.
mockSomeClass.Setup(s => s.SomeMethod(It.IsAny<string>(), out mockIObj.Object).Returns(true);
but it is throwing this error -> "A property or indexer may not be passed as out or ref parameter"
Try “mockIObj.Object” . This should pass in the mocked object rather than the mocked instance
I Found other way to resolve this issue.
This method public bool SomeMethod(string input, out IObj outputObj)
was calling one another method like this public bool oneAnotherMethod(string input, out string outputResponse) mocking this method resolve the issue.
I was not knowing that mocking internal calls can propagate above the calling chain.
Thanks for all the help.
I used to write my tests with RhinoMocks and have switched to NSubstitute.
Now I have a problem concerning ordered test.
Lets say I have three small classes like
public interface IProvider
{
int GetData();
}
public class Provider : IProvider
{
public int GetData()
{
return 3;
}
}
public interface ICalculator
{
int Calculate(int data);
}
public class Calculator : ICalculator
{
public int Calculate(int data)
{
if (data < 3)
{
return data;
}
return data * 2;
}
}
public class Operator
{
public void Operate(IProvider provider, ICalculator calculator)
{
int version = provider.GetData();
this.Result = calculator.Calculate(version);
}
public int Result
{
get;
private set;
}
}
When I write an ordered test using RhinoMocks, I can define the behaviour for the mocked classes like this:
[Test]
public void RhinoMockOrderedTest()
{
var mockRepository = new MockRepository();
var provider = mockRepository.DynamicMock<IProvider>();
var calculator = mockRepository.DynamicMock<ICalculator>();
using (mockRepository.Ordered())
{
provider.Expect(p => p.GetData()).Return(4);
calculator.Expect(c => c.Calculate(4)).Return(9);
}
mockRepository.ReplayAll();
var op = new Operator();
op.Operate(provider, calculator);
mockRepository.VerifyAll();
Assert.That(op.Result, Is.EqualTo(9));
}
Now I was trying to write an ordered test like the one above using NSubstitute, where I was also trying to check the call order and using defined return values:
[Test]
public void NSubstituteOrderedTest()
{
var provider = Substitute.For<IProvider>();
var calculator = Substitute.For<ICalculator>();
var op = new Operator();
op.Operate(provider, calculator);
Received.InOrder(() =>
{
provider.GetData().Returns(4);
calculator.Calculate(4).Returns(9);
});
Assert.That(op.Result, Is.EqualTo(9));
}
Unfortunalely this does not work. It seems to me, when I try to use .Returns for a methon inside of the Received.InOrder - Action, it will alwys fail like this:
NSubstitute.Exceptions.CouldNotSetReturnDueToMissingInfoAboutLastCallException
: Could not find information about the last call to return from.
Make sure you called Returns() after calling your substitute (for
example: mySub.SomeMethod().Returns(value)), and that you are not
configuring other substitutes within Returns() (for example, avoid
this: mySub.SomeMethod().Returns(ConfigOtherSub())).
If you substituted for a class rather than an interface, check that
the call to your substitute was on a virtual/abstract member. Return
values cannot be configured for non-virtual/non-abstract members.
Correct use: mySub.SomeMethod().Returns(returnValue);
Potentially problematic use:
mySub.SomeMethod().Returns(ConfigOtherSub()); Instead try: var
returnValue = ConfigOtherSub();
mySub.SomeMethod().Returns(returnValue);
How can I write this test using NSubstitute ?
Thanks,
Nico
NSubstitute works differently to Rhino Mocks here -- it only supports Arrange-Act-Assert (AAA) style tests. This means we need to stub out calls we're interested in (arrange), run the code we want to test (act), then assert the results are as expected (assert).
Received.InOrder is only for assertions, and works like NSubstitute's Received() method for each call. Returns arranges for a call to return a particular result. NSubstitute does not allow us to mix the two. We can't do sub.Received().Calculate().Returns(42), and it does not make sense to in AAA as there is little point in stubbing a return value after asserting we have already acted on the subject being tested and received all required calls.
Here is a passing version of the test from the question that separates the stubbing/arranging from the assertions:
[Test]
public void NSubstituteOrderedTest() {
// Arrange
var provider = Substitute.For<IProvider>();
var calculator = Substitute.For<ICalculator>();
provider.GetData().Returns(4);
calculator.Calculate(4).Returns(9);
// Act
var op = new Operator();
op.Operate(provider, calculator);
// Assert
Received.InOrder(() =>
{
provider.GetData();
calculator.Calculate(4);
});
Assert.That(op.Result, Is.EqualTo(9));
}
Aside: I know this is a simplified example, but I think it's worth noting that in many cases we can get away without testing the call ordering. For this simple case, we know GetData() is called first, as its value is passed to Calculate(), so the order is enforced via the data dependency. If the end result is correct, we know the call chain was correct. For more complicated cases we can use types for this (Connect() returns ConnectedDb, then Query(ConnectedDb db) ensures Connect() was called first.
Relying on knowledge of the implementation details of the code being tested (such as call ordering) can lead to brittle tests (i.e. they fail with small changes that should not affect the overall result), so it is best to avoid this where possible.
However, even with this disclaimer, it is sometimes useful to assert call order instead, so I hope this answer clears up this NSubstitute feature for you. :)
I am writing tests for our C# 7 application and struggle with mocking an Extension method. I am using TypeMock 8.6.10.3.
Here is a simplified example:
internal class InnerClass
{
private readonly string _description;
public InnerClass(string description)
{
_description = description;
}
public string GetDescription()
{
return _description;
}
}
internal class OuterClass
{
public void DoSthWithExtension(int someNumber)
{
var innerClass = new InnerClass("InnerClassDescription");
innerClass.Extension(someNumber);
}
}
internal static class Extensions
{
public static void Extension(this InnerClass innerClass, int someNumber)
{
var d = innerClass.GetDescription();
}
}
public void TestExtension()
{
// I want to fake the method "InnerClass.Extension()"
// which is called by "OuterClass.DoSthWithExtension()".
// I don't have access to the InnerClass instance though.
// So unfortunately I have to fake them all.
var fakedInnerClasses = Isolate.Fake.AllInstances<InnerClass>();
Isolate.WhenCalled(() => Extensions.Extension(fakedInnerClasses, 11)).WithExactArguments().DoInstead(
c =>
{
// The test doesn't go in here. The second parameter is correct,
// the first one obviously not. But what is expected as a first parameter then?
var oc2 = new OuterClass();
// Here I call InnerClass.Extension() again.
// The test should now go into the faked method underneath.
oc2.DoSthWithExtension(22);
});
Isolate.WhenCalled(() => Extensions.Extension(fakedInnerClasses, 22)).WithExactArguments().DoInstead(
c =>
{
// As above, the test code doesn't go in here.
});
// In here an instance of InnerClass is created and
// InnerClass.Extension(11) is called.
var oc1 = new OuterClass();
oc1.DoSthWithExtension(11);
}
As the this parameter of the Extension method I choose the faked instances of InnerClass. Thats what I assume is needed. But TypeMock does not bring me into the faked method. Obviously its the wrong parameter. But which one should I choose then?
Based on comments and updated question, the part that is confusing is why the other outer class is needed. The shown inner class has no dependency on the outer. Why would the mock then need to create a new outer class?
That aside, based on the docs its appears that you need to setup the extension class so that you can fake the static extension calls.
Isolate.Fake.StaticMethods(typeof(Extensions));
//...
Original answer
Do not fake the extension method in this case. You know what the extension method calls. so fake that.
public void TestExtension() {
//Arrange
string expected = "Fake result";
var fakedInnerClasses = Isolate.Fake.AllInstances<InnerClass>();
Isolate.WhenCalled(() => fakedInnerClasses.GetDescription())
.WillReturn(expected);
var subject = new OuterClass();
//Act
subject.DoSthWithExtension();
//Assert
//...
}
So now when the outer is called and the extension method invoked, it will be acting on the mock controlled by you.
I want to test a void method with Mock.
public class ConsoleTargetBuilder : ITargetBuilder
{
private const string CONSOLE_WITH_STACK_TRACE = "consoleWithStackTrace";
private const string CONSOLE_WITHOUT_STACK_TRACE = "consoleWithoutStackTrace";
private LoggerModel _loggerModel;
private LoggingConfiguration _nLogLoggingConfiguration;
public ConsoleTargetBuilder(LoggerModel loggerModel, LoggingConfiguration nLogLoggingConfiguration)
{
_loggerModel = loggerModel;
_nLogLoggingConfiguration = nLogLoggingConfiguration;
}
public void AddNLogConfigurationTypeTagret()
{
var consoleTargetWithStackTrace = new ConsoleTarget();
consoleTargetWithStackTrace.Name = CONSOLE_WITH_STACK_TRACE;
consoleTargetWithStackTrace.Layout = _loggerModel.layout + "|${stacktrace}";
_nLogLoggingConfiguration.AddTarget(CONSOLE_WITH_STACK_TRACE, consoleTargetWithStackTrace);
var consoleTargetWithoutStackTrace = new ConsoleTarget();
consoleTargetWithoutStackTrace.Name = CONSOLE_WITHOUT_STACK_TRACE;
consoleTargetWithoutStackTrace.Layout = _loggerModel.layout;
_nLogLoggingConfiguration.AddTarget(CONSOLE_WITHOUT_STACK_TRACE, consoleTargetWithoutStackTrace);
}
The thing is I am not sure how to test it. I have my primary code.
public class ConsoleTargetBuilderUnitTests
{
public static IEnumerable<object[]> ConsoleTargetBuilderTestData
{
get
{
return new[]
{
new object[]
{
new LoggerModel(),
new LoggingConfiguration(),
2
}
};
}
}
[Theory]
[MemberData("ConsoleTargetBuilderTestData")]
public void ConsoleTargetBuilder_Should_Add_A_Console_Target(LoggerModel loggerModel, LoggingConfiguration nLogLoggingConfiguration, int expectedConsoleTargetCount)
{
// ARRANGE
var targetBuilderMock = new Mock<ITargetBuilder>();
targetBuilderMock.Setup(x => x.AddNLogConfigurationTypeTagret()).Verifiable();
// ACT
var consoleTargetBuilder = new ConsoleTargetBuilder(loggerModel, nLogLoggingConfiguration);
// ASSERT
Assert.Equal(expectedConsoleTargetCount, nLogLoggingConfiguration.AllTargets.Count);
}
Please guide me to the right direction.
It looks to me like you don't need a mock at all. You are testing AddNLogConfigurationTypeTagret. Not the constructor.
[Theory]
[MemberData("ConsoleTargetBuilderTestData")]
public void ConsoleTargetBuilder_Should_Add_A_Console_Target(LoggerModel loggerModel, LoggingConfiguration nLogLoggingConfiguration, int expectedConsoleTargetCount)
{
// ARRANGE
var consoleTargetBuilder = new ConsoleTargetBuilder(loggerModel, nLogLoggingConfiguration);
// ACT
consoleTargetBuilder.AddNLogConfigurationTypeTagret();
// ASSERT
Assert.Equal(expectedConsoleTargetCount, nLogLoggingConfiguration.AllTargets.Count);
}
If you don't want to call AddNLogConfigurationTypeTagret yourself, it should be called in the constructor. This changes the test to this :
[Theory]
[MemberData("ConsoleTargetBuilderTestData")]
public void ConsoleTargetBuilder_Should_Add_A_Console_Target(LoggerModel loggerModel, LoggingConfiguration nLogLoggingConfiguration, int expectedConsoleTargetCount)
{
// ARRANGE
// ACT
var consoleTargetBuilder = new ConsoleTargetBuilder(loggerModel, nLogLoggingConfiguration);
// ASSERT
Assert.Equal(expectedConsoleTargetCount, nLogLoggingConfiguration.AllTargets.Count);
}
and the class constructor should then be :
public ConsoleTargetBuilder(LoggerModel loggerModel, LoggingConfiguration nLogLoggingConfiguration)
{
_loggerModel = loggerModel;
_nLogLoggingConfiguration = nLogLoggingConfiguration;
AddNLogConfigurationTypeTagret();
}
Please guide me to the right direction, I want two things. A) the method was called. B) two targets were added. So the expected count is 2.
A) If you wish to verify that method AddNLogConfigurationTypeTagret was called, then you need to test it on the code which is calling this method. E.g. something like the class ConsoleTargetBuilderClient which is an hypothetical example of a class which is using the ITargetBuilder (in your own code you should have some place where the class ConsoleTargetBuilder is used).
public class ConsoleTargetBuilderClient
{
private ITargetBuilder _builder;
public ConsoleTargetBuilderClient(ITargetBuilder builder)
{
_builder = builder;
}
public void DoSomething()
{
_builder.AddNLogConfigurationTypeTagret();
}
}
Then you can have a test which verifies that the method DoSomething called the method AddNLogConfigurationTypeTagret. For that purpose you can use a mock of ConsoleTargetBuilder because you test interaction with it. Test might look like this:
public void DoSomething_WhenCalled_AddNLogConfigurationTypeTagretGetsCalled()
{
// Arrange
bool addNLogConfigurationTypeTagretWasCalled = false;
Mock<ITargetBuilder> targetBuilderMock = new Mock<ITargetBuilder>();
targetBuilderMock.Setup(b => b.AddNLogConfigurationTypeTagret())
.Callback(() => addNLogConfigurationTypeTagretWasCalled = true);
ConsoleTargetBuilderClient client = new ConsoleTargetBuilderClient(targetBuilderMock.Object);
// Act
client.DoSomething();
// Assert
Assert.IsTrue(addNLogConfigurationTypeTagretWasCalled);
}
B) If you wish to verify that the targets were added you need to test the code itself (not mock of it). Test might look like this:
public void AddNLogConfigurationTypeTagret_WhenCalled_ConsoleTargetsAdded()
{
// Arrange
const int expectedConsoleTargetCount = 2;
var loggerModel = new LoggerModel();
var nLogLoggingConfiguration = new LoggingConfiguration();
var consoleTargetBuilder = new ConsoleTargetBuilder(loggerModel, nLogLoggingConfiguration);
// Act
consoleTargetBuilder.AddNLogConfigurationTypeTagret();
// Assert
Assert.AreEqual<int>(expectedConsoleTargetCount, nLogLoggingConfiguration.AllTargets.Count);
}
Note: google value-based vs. state-based vs. interaction testing.
Generally speaking, you shouldn't be mocking the class you want to test, you should be mocking it's dependencies. When you start mocking the class you're trying to test things often get entwined leading to brittle tests and it's difficult to determine if you're testing your code, or you mocking setup, or both.
The method AddNLogConfigurationTypeTagret is a public method on the class you're testing, so as #Philip has said, you should probably just be calling it from your test, or it should be called from your constructor. If you goal is for it to be called from your constructor, then I'd suggest that it should probably be a private method unless there's a reason for it to be called from outside the class.
As far as testing the effects of a void method call, you're interested in the state change caused by the method. In this instance, whether or not the _nLoggingConfiguration has two targets added with the correct attributes. You don't show us the nLoggingConfiguration.AllTargets property, but I would assume from the fact that you're using the Count property in your test, that you could simply inspect the items in the list to confirm that the correct name and layout have been added to the correct target type.
// Assert
targetBuilderMock.Verify(x => x.AddNLogConfigurationTypeTagret(), Times.Once());
Mock Framework: Moq
Test Framework: NUnit
I feel like there's a simple answer to this and I'm just overlooking it, but I can't for the life of me figure out why this is giving me grief.
I have two mocks here, and I'm trying to verify that the unit under test is setting one mock's property to the other mock's property, as such:
[TestFixture]
public class Testmock
{
protected Mock<IOne> mockOne;
protected Mock<ITwo> mockTwo;
protected Controller UnitUnderTest;
[SetUp]
public void Setup()
{
mockOne = new Mock<IOne>();
mockTwo = new Mock<ITwo>();
UnitUnderTest = new Controller(mockOne.Object, mockTwo.Object);
}
[Test]
public void Test1()
{
string testString = "test";
mockOne.SetupGet(o => o.Val).Returns(testString);
UnitUnderTest.CopyVal();
mockTwo.VerifySet(t => t.Val = mockOne.Object.Val);
}
}
public interface IOne
{
string Val { get; set; }
}
public interface ITwo
{
string Val { get; set; }
}
public class Controller
{
IOne one;
ITwo two;
public Controller(IOne one, ITwo two)
{
this.one = one;
this.two = two;
}
public void CopyVal()
{
two.Val = one.Val;
}
}
When I run this test, it returns an error at VerifySet that says:
Expected invocation on the mock at least once, but was never performed: t => t.Val = (String)null
But underneath that, says:
Performed invocations: ITwo.Val = "test"
So I know for certain that ITwo.Val is getting set with IOne.Val in my Controller, but I must be setting up the mock wrong here for the VerifySet. I can replace the VerifySet with the string directly, e.g.:
mockTwo.VerifySet(t => t.Val = testString);
and the test will pass. Since mockOne.Object.Val is SetupGet to return testString, I don't quite understand why I can't use mockOne.Object.Val in place of testString in the VerifySet.
I am not sure why mockOne.Object.Val returns null in the context of VerifySet. I believe it has something to do with Moq internal implementation (digging Moq sources can reveal the reason for such behavior).
However I can tell you how to change your test to make it work without using testString variable in VerifySet(). You should use It.Is(x => x == mockOne.Object.Val) instead of referring the mock property directly. Please see below:
[Test]
public void Test1()
{
string testString = "test";
mockOne.SetupGet(o => o.Val).Returns(testString);
UnitUnderTest.CopyVal();
mockTwo.VerifySet(t => t.Val = It.Is<string>(x => x == mockOne.Object.Val));
}
Hope this helps.