I am new to ReactiveUI and trying to test a view model that looks like this:
public interface IService
{
Task<SessionModel> GetData(string id);
}
/// Provides a group of schedulers available to be used
public interface ISchedulers
{
IScheduler Default { get; }
IScheduler Dispatcher { get; }
}
public class MyVm : ReactiveObject
{
IService service;
public MyVm(ISchedulers schedulers, IService service)
{
this.service = service;
this.session = this.WhenAnyValue(x => x.SessionId)
.SelectMany(SearchSession)
.ObserveOn(schedulers.Default)
.ToProperty(this, x => x.Session);
}
private async Task<SessionModel> SearchSession(string id)
{
return await this.service.GetData(id);
}
private string sessionId;
public string SessionId
{
get => sessionId;
set => this.RaiseAndSetIfChanged(ref sessionId, value);
}
readonly ObservableAsPropertyHelper<SessionModel> session;
public SessionModel Session
{
get { return session.Value; }
}
}
public class SessionModel { }
I'm mocking the service call to return dummy data, but not sure what I need to do with a TestScheduler in order to get the SelectMany to work.
Here's a test class that shows how i would create a test for the view model. The goal is to eventually be able to check that the model got set:
[TestClass]
public class MyVmTests
{
[TestMethod]
public void CreateClass
{
var subject = new MyVm(/*pass in mocks*/);
subject.SessionId="test";
Assert.IsNotNull(subject.Session);
}
}
I don't think using TestScheduler is necessary. The following passes for me (using Moq):
var mockSchedulers = new Mock<ISchedulers>();
mockSchedulers.Setup(s => s.Default).Returns(Scheduler.Immediate);
var id = "123";
var mockService = new Mock<IService>();
var returnSession = new SessionModel();
mockService.Setup(s => s.GetData(It.Is<string>(i => i == id)))
.ReturnsAsync(returnSession);
var target = new MyVm(mockSchedulers.Object, mockService.Object);
target.SessionId = id;
Assert.IsNotNull(target.Session);
Assert.AreEqual(returnSession, target.Session);
TestScheduler is best when you're trying to test something with time (like a Delay, proving that the Delay actually happened). You're not really doing that here.
I have the following interfaces
public interface IRibbonCommandsProvider
{
IEnumerable<IRibbonCommand> GetRibbonCommands();
}
public interface IRibbonCommand
{
string Group { get; }
string Tab { get; }
string Name { get; }
string Image { get; }
void Execute();
}
And the follwing substitution code:
public class TabsViewModelTests
{
[Fact]
public void Initialize_BuildsCorrectRibbonTree()
{
var commands = Substitute.For<IRibbonCommandsProvider>();
commands.GetRibbonCommands().Returns(
new[]
{
new RibbonCommand { Tab = "Tab1", Group = "Group1", Name = "Name1" },
new RibbonCommand { Tab = "Tab1", Group = "Group1", Name = "Name2" },
new RibbonCommand { Tab = "Tab2", Group = "Group1", Name = "Name3" },
new RibbonCommand { Tab = "Tab2", Group = "Group2", Name = "Name3" }
});
...
}
private class RibbonCommand : IRibbonCommand
{
public string Group { get; set; }
public string Tab { get; set; }
public string Name { get; set; }
public string Image { get; set; }
public void Execute() {}
}
}
Using NSubstitute, is there a clever way to get rid of the stub RibbonCommand class (that is nothing but a fake IRibbonCommand implementation - and that's NSubstitute's job) and still have list of fake ribbon commands that is as easily readable as the above?.
I can't come up with a readable way using NSubsitute's .Returns() fluent method without ending with a lot more (and unreadable) code.
Update:
A cool NSubstitute extension method could look like this. I just don't know if and how this can be built:
public static ConfiguredCall ReturnsMany<T>(
this IEnumerable<T> value,
Action<T> configureThis,
params Action<T>[] configureThese)
{
...
}
It would be used like this:
commands.GetRibbonCommands().ReturnsMany(
subst =>
{
subst.Tab.Returns("Tab1");
subst.Group.Returns("Group1");
subst.Name.Returns("Name1");
},
subst =>
{
subst.Tab.Returns("Tab1");
subst.Group.Returns("Group1");
subst.Name.Returns("Name2");
},
subst =>
{
subst.Tab.Returns("Tab2");
subst.Group.Returns("Group1");
subst.Name.Returns("Name3");
},
subst =>
{
subst.Tab.Returns("Tab2");
subst.Group.Returns("Group1");
subst.Name.Returns("Name3");
});
I think what you've got is very good — quite succinct and clear.
If you really want to get rid of the class you can use a substitute creation method for IRibbonCommand:
private IRibbonCommand Create(string tab, string group, string name)
{
var cmd = Substitute.For<IRibbonCommand>();
cmd.Tab.Returns(tab);
cmd.Group.Returns(group);
cmd.Name.Returns(name);
return cmd;
}
[Fact]
public void Initialize_BuildsCorrectRibbonTree()
{
var ribbonCommands = new[] {
Create("tab1", "group1", "name1"),
Create("tab1", "group1", "name2"),
Create("tab2", "group1", "name3"),
Create("tab2", "group1", "name4")
};
var commands = Substitute.For<IRibbonCommandsProvider>();
commands.GetRibbonCommands().Returns(ribbonCommands);
// ...
}
This doesn't buy you much, although it does mean your test code will be more protected from changes to the IRibbonCommand interface (e.g. an additional property will not require changing your test code), and means you can check received calls and stub other calls on individual items.
Aside: Can use argument names if you want to more closely match the original code:
Create(tab: "tab1", group: "group1", name: "name1"),
As alternative you may setup Command inside test. Then move config func out of the test and optionally generalize for other types as you go. Yagni it.
UPDATED to working test
[Test]
public void Test()
{
Func<Action<IRibbonCommand>, IRibbonCommand> cmd = config =>
{
var c = Substitute.For<IRibbonCommand>();
config(c);
return c;
};
var ribbonCommands = new[]
{
cmd(c => { c.Tab.Returns("Tab1"); c.Group.Returns("Group1"); c.Name.Returns("Name1"); }),
cmd(c => { c.Tab.Returns("Tab1"); c.Group.Returns("Group1"); c.Name.Returns("Name2"); }),
cmd(c => { c.Tab.Returns("Tab2"); c.Group.Returns("Group1"); c.Name.Returns("Name3"); }),
cmd(c => { c.Tab.Returns("Tab2"); c.Group.Returns("Group1"); c.Name.Returns("Name4"); })
};
var commandsProvider = Substitute.For<IRibbonCommandsProvider>();
commandsProvider.GetRibbonCommands().Returns(ribbonCommands);
}
I don't see anything out of the box that's going to do what you're after. One option might be for you to write your own extension method to make the construction easier. So, something like this:
public static class ReadOnlySubstitute {
static public T For<T>(object source) where T : class {
var sub = Substitute.For<T>();
foreach (var prop in source.GetType().GetProperties()) {
sub.GetType().GetProperty(prop.Name).GetValue(sub).Returns(prop.GetValue(source));
}
return sub;
}
}
The above code essentially creates a substitute for the given interface and then sets up a return on each of properties specified in the supplied object.
This could then be used in your test like this to supply anonymous objects with the parameters:
[Test]
public void Initialize_BuildsCorrectRibbonTree() {
var ribbonCommands = new[]
{
ReadOnlySubstitute.For<IRibbonCommand>(new {Tab="Tab1", Group="Grp1", Name="Nam1"}),
ReadOnlySubstitute.For<IRibbonCommand>(new {Tab="Tab1", Group="Grp1", Name="Nam2"}),
ReadOnlySubstitute.For<IRibbonCommand>(new {Tab="Tab2", Group="Grp1", Name="Nam3"}),
ReadOnlySubstitute.For<IRibbonCommand>(new {Tab="Tab2", Group="Grp2", Name="Nam3"})
};
var commands = Substitute.For<IRibbonCommandsProvider>();
commands.GetRibbonCommands().Returns(ribbonCommands);
....
}
It's not quite as concise as using the RibbonCommand class, since you have to construct the array before passing it into the Returns method because NSubstitute gets confused if you try to setup the Returns on the elements at the same time as on the GetRibbonCommands, but I think it's fairly close.
This is really an enhancement (subjective) of #dadhi's answer, combined with an answer from #David Tchepak to a different question.
So, rather than having to create a new Func for each interface your want to use, as described by #dadhi, you can instead create a generic method that takes an Action. You could be this in a shared class, something like this:
static class ConfiguredSub {
public static T For<T>(Action<T> config) where T : class {
var c = Substitute.For<T>();
config(c);
return c;
}
}
The problem that I encountered with my other answer was that if you have nested Returns, NSubstitute gets confused and starts throwing exceptions. It turns out that as described by #David here, you can pass a Func to defer the execution and get round this issue. If you combine these two things, then you get something pretty close to what you're after.
[Test]
public void Initialize_BuildsCorrectRibbonTree() {
var commands = Substitute.For<IRibbonCommandsProvider>();
commands.GetRibbonCommands().Returns(x => new[] {
ConfiguredSub.For<IRibbonCommand>(subst =>
{
subst.Tab.Returns("Tab1");
subst.Group.Returns("Group1");
subst.Name.Returns("Name1");
}),
ConfiguredSub.For<IRibbonCommand>(subst =>
{
subst.Tab.Returns("Tab1");
subst.Group.Returns("Group1");
subst.Name.Returns("Name2");
}),
ConfiguredSub.For<IRibbonCommand>(subst =>
{
subst.Tab.Returns("Tab2");
subst.Group.Returns("Group1");
subst.Name.Returns("Name3");
}),
ConfiguredSub.For<IRibbonCommand>(subst =>
{
subst.Tab.Returns("Tab2");
subst.Group.Returns("Group1");
subst.Name.Returns("Name4");
})
});
// ...
}
I wanna test my method with mock but it throw this exception. My class is this (this class do some simple actions on a file as though unzipping the file) :
public class FileActions
{
public virtual void Decompress(FileInfo fileInfo, DirectoryInfo directoryInfo)
{
ZipFile.ExtractToDirectory(fileInfo.FullName, directoryInfo.FullName);
}
public virtual FileInfo GetConvertedFileToZip(FileInfo fileInfo)
{
try
{
var changeExtension = Path.ChangeExtension(fileInfo.FullName, "zip");
File.Move(fileInfo.FullName, changeExtension);
return new FileInfo(changeExtension);
}
catch (Exception)
{
throw new FileNotFoundException();
}
}
}
and this is my test :
public void TestMockedMethodForNotNull()
{
var mock = new Mock<FileActions>();
var fInfo = new FileInfo(#"D:\ZipFiles\elmah.nupkg");
mock.Setup(s => s.GetConvertedFileToZip(fInfo)).Verifiable();
mock.VerifyAll();
}
So, why does it get this Error :
Moq.MockVerificationException: The following setups were not matched:
FileActions2 s => s.GetConvertedFileToZip(D:\ZipFiles\elmah.nupkg)
There are several issues with your Unit Test. I will only highlight the mocking side of things, as it relevant to the question you ask. Also your question has refer to "FileActions2", and I think this
a mistake when you originally add the question.
You Test:
[TestMethod]
public void TestMockedMethodForNotNull()
{
var mock = new Mock<FileActions>();
var fileInfo = new FileInfo(#"D:\ZipFiles\elmah.nupkg");
mock.Setup(s => s.GetConvertedFileToZip(fileInfo)).Verifiable();
mock.VerifyAll();
}
The way you have written this test, Moq won't verify on GetConvertedFileToZip
This test fail fundamentally because Moq cannot provide an override for a virtual method GetConvertedFileToZip. You must create a proxy i,e mock.Object.
If you modify your test in such a way so your SUT (Sysytem Under Test), consumes an instance of the mocked object/proxied object
your verify would work partially (partially means you are heading right direction). Still something else to fix which I have described below.
Assuming your SUT is like below
public class Sut
{
public void Do(FileActions fileActions)
{
var fileInfo = new FileInfo(#"D:\ZipFiles\elmah.nupkg");
var s = fileActions.GetConvertedFileToZip(fileInfo);
}
}
Your Test
[TestMethod]
public void TestMockedMethodForNotNull()
{
var mock = new Mock<FileActions>();
var fileInfo = new FileInfo(#"D:\ZipFiles\elmah.nupkg");
mock.Setup(s => s.GetConvertedFileToZip(fileInfo)).Verifiable();
var sut = new Sut();
sut.Do(mock.Object);
mock.VerifyAll();
}
This would produce an exception. This is because fileInfo you have setup on does not match the verification, when invoke via the Sut.
If you were to modify this test as below, this would succeed
[TestMethod]
public void TestMockedMethodForNotNull()
{
var mock = new Mock<FileActions>();
//var fileInfo = new FileInfo(#"D:\ZipFiles\elmah.nupkg");
mock.Setup(s => s.GetConvertedFileToZip(It.IsAny<FileInfo>())).Verifiable();
var sut = new Sut();
sut.Do(mock.Object);
mock.VerifyAll();
}
I am getting started with Automoq. I was trying to do something like this:
mocker.GetMock<IMyObjectToTweak>();
var line = mocker.Resolve<IMyObjectToTweak>();
line.PropertyOne = .75;
line.PropertyTwo = 100;
MyCalc calc = new MyCalc();
calc.Multiply(line);
Assert.AreEqual(75, line.result);
This runs bu fails. My properties do not get set. Am I missing the idea of Automoq? What is a good resource/tutorial?
To set property with Moq (this is what Automoq uses to create mock objects) you have to use different calls, - Setup, SetupGet or SetupProperty:
var line = mocker.Resolve<IMyObjectToTweak>();
// each does the same thing - "tells" PropertyOne to return .75 upon get
line.Setup(l => l.PropertyOne).Returns(.75);
line.SetupGet(l => l.PropertyOne).Returns(.75);
line.SetupProperty(l => l.PropertyOne, .75);
I suggest expose a Result property in your Sut (System Under test)
[TestClass]
public class SomeTest : ControllerTestBase
{
[TestMethod]
public void MethodNameOrSubject_ScenarioOrCondition_ExpectedBehaviourOrReturnValue()
{
var mock = _autoMoqContainer.GetMock<IMyObjectToTweak>();
var line = _autoMoqContainer.Resolve<IMyObjectToTweak>();
mock.Setup(x => x.PropertyOne).Returns(.75);
mock.Setup(x => x.PropertyTwo).Returns(100);
MyCalc calc = new MyCalc();
calc.Multiply(line);
Assert.AreEqual(75, calc.Result);
}
}
public interface IMyObjectToTweak
{
double PropertyOne { get; set; }
int PropertyTwo { get; set; }
}
public class MyCalc
{
public double Result { get; set; }
public void Multiply(IMyObjectToTweak line)
{
Result = line.PropertyOne*line.PropertyTwo;
}
}
Not related - But read my post more on AutoMocking
http://www.dotnetcurry.com/ShowArticle.aspx?ID=767
Below is a class (Class1) that I want to test, but I'm not fully satisfied with my Unit Test. Please see below code samples.
System Under Test
public interface IRepository {
string GetParameter(int id);
}
public class Repository {
public string GetParameter(int id) {
return "foo";
}
}
public class ErrorInfo {
public string ErrorCodes { get; set; }
}
public interface IErrorProvider {
ErrorInfo BuildErrorMessage(string errorCodes);
}
public class ErrorProvider {
public ErrorInfo BuildErrorMessage(string errorCodes) {
return new ErrorInfo(){ErrorCodes = errorCodes};
}
}
public class Class1 {
private readonly IRepository _repository;
private readonly IErrorProvider _errorProvider;
public Class1(IRepository repository, IErrorProvider errorProvider) {
_repository = repository;
_errorProvider = errorProvider;
}
public List<ErrorInfo> GetErrorList(int id) {
var errorList = new List<ErrorInfo>();
string paramName = _repository.GetParameter(id);
if (string.IsNullOrEmpty(paramName)) {
string errorCodes = string.Format("{0}, {1}", 200, 201);
var error = _errorProvider.BuildErrorMessage(errorCodes);
errorList.Add(error);
}
return errorList;
}
}
Unit Tests
Below test passes and we check whether the correct error codes being used within the system under test.
[TestMethod]
public void GetErrorList_WhenParameterIsEmpty_ReturnsExpectedErrorCodes2() {
//Arrange
var stubRepo = new Mock<IRepository>();
stubRepo.Setup(x => x.GetParameter(It.IsAny<int>())).Returns(string.Empty);
var stubErrorMock = new Mock<IErrorProvider>();
const int id = 5;
var sut = new Class1(stubRepo.Object, stubErrorMock.Object);
//Act
var result = sut.GetErrorList(id);
//Verify
string verifiableErrorCodes = "200, 201";
stubErrorMock.Verify(x => x.BuildErrorMessage(verifiableErrorCodes));
}
However I would prefer testing the end result. For example, I want to Assert against the error codes that have been used in the production code. Below test fails but I like to know your thoughts on how to Assert against the errorCodes that has been used in the system under test.
[TestMethod]
public void GetErrorList_WhenParameterIsEmpty_ReturnsExpectedErrorCodes1() {
//Arrange
var stubRepo = new Mock<IRepository>();
stubRepo.Setup(x => x.GetParameter(It.IsAny<int>())).Returns(string.Empty);
string expectedErrorCodes = "200, 201";
var stubErrorRepo = new Mock<IErrorProvider>();
stubErrorRepo.Setup(e => e.BuildErrorMessage(It.IsAny<string>()));
const int id = 5;
var sut = new Class1(stubRepo.Object, stubErrorRepo.Object);
//Act
var result = sut.GetErrorList(id);
//Assert
Assert.AreEqual(expectedErrorCodes, result.Single().ErrorCodes);
}
What would be the correct way to test this error codes that has been used in the system?
I suggest to mock only the IRepository and use a real IErrorProvider. Then you can call GetErrorList(id) and check the result.
There is not really right or wrong answer and we have decided to use the Assert test as it test the end result.
I took the TDD approach and re-implemented/analysed as below.
Start with a failing test (to simplify the code I removed the Repository from both test and the sut)
//AssertTest
[TestMethod]
public void GetErrorList_WhenParameterIsEmpty_ReturnsExpectedErrorCodes1()
{
//Arrange
const string expectedErrorCodes = "200, 201";
var stubErrorRepo = new Mock<IErrorProvider>();
stubErrorRepo.Setup(e => e.BuildErrorMessage(expectedErrorCodes)).Returns(new ErrorInfo() { ErrorCodes = expectedErrorCodes });
var sut = new Class1(stubErrorRepo.Object);
//Act
var result = sut.GetErrorList();
//Assert
Assert.AreEqual(expectedErrorCodes, result.Single().ErrorCodes);
}
//SUT
public IEnumerable<ErrorInfo> GetErrorList(int id)
{
yield return new ErrorInfo();
}
As you would expect the test fail.
Now if write enough production code to make this test pass.
public IEnumerable<ErrorInfo> GetErrorList()
{
yield return _errorProvider.BuildErrorMessage("200, 201");
}
The VerifyTest would still fail for the above SUT.
//VerifyTest
[TestMethod]
public void GetErrorList_WhenParameterIsEmpty_ReturnsExpectedErrorCodes2()
{
//Arrange
var stubErrorMock = new Mock<IErrorProvider>();
var sut = new Class1(stubErrorMock.Object);
//Act
sut.GetErrorList();
//Verify
string verifiableErrorCodes = "200, 201";
stubErrorMock.Verify(x => x.BuildErrorMessage(verifiableErrorCodes));
}
However if I want this test to pass, I can write the below production code as below
public IEnumerable<ErrorInfo> GetErrorList()
{
_errorProvider.BuildErrorMessage("200, 201");
return null;
}
Now the VerifyTest passes, but the AssertTest fails.
Both tests are valid in their own ways. However they test different semantics.
AssertTest test whether the end result contains the correct error codes. Verify test ensures
the method is called with the correct error codes. It is important to note that
the end value of the Assert test is based on the setup method "match" provided by the Moq
framework. In other words the setup dictates what the end result would be.
AssertTest would fail if the setup is configured incorrectly or the production code uses error codes that does not match the setup configuration.
It is preferred to use the AssertTest as it test the end result.