Mocking Sealed Class with RhinoMocks - c#

I am fairly new to TDD and I am trying to mock HttpContextBase in an MVC app. I also need to mock the Response property and the HttpCookieCollection of that.
The HttpCookieCollection class is sealed though and RhinoMocks says it cannot mock sealed classes.
Any advice on how I should tackle this.
My test is below:
[TestMethod]
public void CreateSignInTicketCreateTempCookie()
{
const string email = "dave#somewhere.co.uk";
var mockHttpContextBase = MockRepository.GenerateMock<HttpContextBase>();
var response = MockRepository.GenerateMock<HttpResponseBase>();
var mockUserRepository = MockRepository.GenerateStub<IUserRepository>();
var cookieCollection = MockRepository.GenerateStub<HttpCookieCollection>();
mockHttpContextBase.Stub(x => x.Response).Return(response);
response.Stub(x => x.Cookies).Return(cookieCollection);
var webAuth = new WebAuthenticator(mockUserRepository);
webAuth.CreateSignInTicket(mockHttpContextBase, email);
Assert.IsTrue(mockHttpContextBase.Response.Cookies.Count == 1);
}

I would say mocking HttpCookieCollection is taking things a bit too far - it's just a way of storing cookies - you wouldn't mock an IList<Cookie>, would you?
Simply do
response.Stub(x => x.Cookies).Return(new HttpCookieCollection());
or similar (not used Rhino Mocks so not sure if this is exactly right).

Related

Ways to test SearchResults<T> Class in Azure.Search.Documents v11.2.0

I'm trying to find out a way to unit test the search results from the SearchResults<T> Class with different parameters.
Compared to DocumentSearchResult<T> Class which was in the previous package Microsoft.Azure.Search.Data v10.1.0, SearchResults<T> Class does not have any constructors, just properties and methods.
DocumentSearchResult<T> Class
https://learn.microsoft.com/en-us/dotnet/api/microsoft.azure.search.models.documentsearchresult-1?view=azure-dotnet
SearchResults<T> Class
https://learn.microsoft.com/en-us/dotnet/api/azure.search.documents.models.searchresults-1?view=azure-dotnet
I couldn't seem to find any documentation on that online as it is relatively new, but any ideas or suggestions are most welcome.
Thank you.
All our Azure SDKs for .NET matching package names Azure.* like Azure.Search.Documents are mockable using the same principles as shown here. For pure response objects like SearchResults<T>, we create model factories so that you can create them for testing. In general, there is no other intended purpose for creating them apart from testing.
Using Moq, for example:
// Arrange
var mockResponse = new Mock<Response>();
var mockResults = SearchModelFactory.SearchResults<Model>(new[]
{
SearchModelFactory.SearchResult<Model>(new Model { Name = "a" }, 1.0),
SearchModelFactory.SearchResult<Model>(new Model { Name = "b" }, 0.9),
}, 2, rawResponse: response.Object);
var mockClient = new Mock<SearchClient>();
mockClient.Setup(m => m.Search<Model>(It.IsAny<string>(), It.IsAny<SearchOptions>(), default))
.Returns(Response.FromValue(mockResults, mockResponse.Object));
// Act
var response = mockClient.Object.Search<Model>("anything");
// Assert
Assert.AreEqual(2, response.Value.TotalCount);
See more mocking samples for other ideas.
The SearchModelFactory is the class that will help you to create the models for SearchResults.
This reading can also be helpful for another kind of tests: https://devblogs.microsoft.com/azure-sdk/unit-testing-and-mocking/
Just in case someone else is looking for a version using NSubstitute, here is mine:
public async Task TheTest()
{
// Arrange
var searchResultValues = new List<SearchResult<MyModel>>
{
SearchModelFactory.SearchResult<MyModel>(new MyModel{Id = 1}, score:0.9, highlights:null),
SearchModelFactory.SearchResult<MyModel>(new MyModel{Id = 2}, score:0.8, highlights:null),
};
var searchResults = SearchModelFactory.SearchResults<MyModel>(searchResultValues, totalCount: 2, facets: null, coverage: 1.3, rawResponse: Substitute.For<Response>());
var response = Response.FromValue(searchResults, Substitute.For<Response>());
var searchClient = Substitute.For<SearchClient>();
searchClient.SearchAsync<MyModel>(Arg.Any<string>(), Arg.Any<SearchOptions>()).Returns(Task.FromResult(response));
var sut = new ClassThatUsesTheSearchClient(searchClient);
// Act
var result = await sut.MethodToSearch();
// or directly
var directResult = await searchClient.SearchAsync<MyModel>("text");
// Assert
Assert.AreEqual(2, directResult.Value.TotalCount);
...
}

How to mock IConfiguration.GetValue

I tried in vain to mock a top-level (not part of any section) configuration value (.NET Core's IConfiguration). For example, neither of these will work (using NSubstitute, but it would be the same with Moq or any mock package I believe):
var config = Substitute.For<IConfiguration>();
config.GetValue<string>(Arg.Any<string>()).Returns("TopLevelValue");
config.GetValue<string>("TopLevelKey").Should().Be("TopLevelValue"); // nope
// non generic overload
config.GetValue(typeof(string), Arg.Any<string>()).Returns("TopLevelValue");
config.GetValue(typeof(string), "TopLevelKey").Should().Be("TopLevelValue"); // nope
In my case, I also need to call GetSection from this same config instance.
You can use an actual Configuration instance with in-memory data.
//Arrange
var inMemorySettings = new Dictionary<string, string> {
{"TopLevelKey", "TopLevelValue"},
{"SectionName:SomeKey", "SectionValue"},
//...populate as needed for the test
};
IConfiguration configuration = new ConfigurationBuilder()
.AddInMemoryCollection(inMemorySettings)
.Build();
//...
Now it is a matter of using the configuration as desired to exercise the test
//...
string value = configuration.GetValue<string>("TopLevelKey");
string sectionValue = configuration.GetSection("SectionName").GetValue<string>("SomeKey");
//...
Reference: Memory Configuration Provider
I do not have idea about NSubstitute, but this is how we can do in Moq.
Aproach is same in either cases.
GetValue<T>() internally makes use of GetSection().
You can Mock GetSection and return your Own IConfigurationSection.
This includes two steps.
1). Create a mock for IConfigurationSection (mockSection) & Setup .Value Property to return your desired config value.
2). Mock .GetSection on Mock< IConfiguration >, and return the above mockSection.Object
Mock<IConfigurationSection> mockSection = new Mock<IConfigurationSection>();
mockSection.Setup(x=>x.Value).Returns("ConfigValue");
Mock<IConfiguration> mockConfig = new Mock<IConfiguration>();
mockConfig.Setup(x=>x.GetSection(It.Is<string>(k=>k=="ConfigKey"))).Returns(mockSection.Object);
Mock IConfiguration
Mock<IConfiguration> config = new Mock<IConfiguration>();
SetupGet
config.SetupGet(x => x[It.Is<string>(s => s == "DeviceTelemetryContainer")]).Returns("testConatiner");
config.SetupGet(x => x[It.Is<string>(s => s == "ValidPowerStatus")]).Returns("On");
IConfiguration.GetSection<T> must be mocked indirectly. I don't fully understand why because NSubstitute, if I understand correctly, creates its own implementation of an interface you're mocking on the fly (in memory assembly). But this seems to be the only way it can be done. Including a top-level section along with a regular section.
var config = Substitute.For<IConfiguration>();
var configSection = Substitute.For<IConfigurationSection>();
var configSubSection = Substitute.For<IConfigurationSection>();
configSubSection.Key.Returns("SubsectionKey");
configSubSection.Value.Returns("SubsectionValue");
configSection.GetSection(Arg.Is("SubsectionKey")).Returns(configSubSection);
config.GetSection(Arg.Is("TopLevelSectionName")).Returns(configSection);
var topLevelSection = Substitute.For<IConfigurationSection>();
topLevelSection.Value.Returns("TopLevelValue");
topLevelSection.Key.Returns("TopLevelKey");
config.GetSection(Arg.Is<string>(key => key != "TopLevelSectionName")).Returns(topLevelSection);
// GetValue mocked indirectly.
config.GetValue<string>("TopLevelKey").Should().Be("TopLevelValue");
config.GetSection("TopLevelSectionName").GetSection("SubsectionKey").Value.Should().Be("SubsectionValue");
I could imagine in some rare scenarios it is needed but, in my humble opinion, most of the time, mocking IConfiguration highlight a code design flaw.
You should rely as much as possible to the option pattern to provide a strongly typed access to a part of your configuration. Also it will ease testing and make your code fail during startup if your application is misconfigured (instead than at runtime when the code reading IConfiguration is executed).
If you really(really) need to mock it then I would advice to not mock it but fake it with an in-memory configuration as explained in #Nkosi's answer
While Nkosi's answer works great for simple structures, sometimes you want to be able to have more complex objects (like arrays) without repeating the whole section path and to be able to use the expected types themselves. If you don't really care too much about performance (and should you in your unit tests?) then this extension method might be helpful.
public static void AddObject(this IConfigurationBuilder cb, object model) {
cb.AddJsonStream(new MemoryStream(Encoding.UTF8.GetString(JsonConvert.SerializeObject(model))));
}
And then use it like this
IConfiguration configuration = new ConfigurationBuilder()
.AddObject(new {
SectionName = myObject
})
.Build();
Use SetupGet method to mock the Configuration value and return any string.
var configuration = new Mock<IConfiguration>();
configuration.SetupGet(x => x[It.IsAny<string>()]).Returns("the string you want to return");
We need to mock IConfiguration.GetSection wichs is executed within GetValue extension method.
You inject the IConfiguration:
private readonly Mock<IConfiguration> _configuration;
and the in the //Arrange Section:
_configuration.Setup(c => c.GetSection(It.IsAny())).Returns(new Mock().Object);
It worked like a charm for me.
I've found this solution to work reliably for me for my XUnit C# tests & corresponding C# code:
In Controller
string authConnection = this._config["Keys:AuthApi"] + "/somePathHere/Tokens/jwt";
In XUnit Test
Mock<IConfiguration> mockConfig = new Mock<IConfiguration>();
mockConfig.SetupGet(x => x[It.Is<string>(s => s == "Keys:AuthApi")]).Returns("some path here");

Fake HttpContext.Current.Server.MapPath for unit test

I have a test which fails on this line. I've figured out that it is because of the HttpContext inside of my GetProofOfPurchase method. Here is the line I'm failing on:
var image = Image.GetInstance(HttpContext.Current.Server.MapPath(GlobalConfig.HeaderLogo));
This is my test:
[Test]
public void GetProofOfPurchase_Should_Call_Get_On_ProofOfPurchaseRepository()
{
string customerNumber = "12345";
string orderNumber = "12345";
string publicItemNumber = "12345";
var result = new ProofOfPurchase();
this.proofOfPurchaseRepository.Expect(p => p.Get(new KeyValuePair<string,string>[0])).IgnoreArguments().Return(result);
this.promotionTrackerService.GetProofOfPurchase(customerNumber, orderNumber, publicItemNumber);
this.promotionTrackerRepository.VerifyAllExpectations();
}
The test fails on promotionTrackerService.GetProofOfPurchase line. How do I fake the HttpContext in this situation? I have searched Stack Overflow for similar issues to mine but I'm unable to get anything to work.
I've tried doing this:
var image = Image.GetInstance(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, GlobalConfig.HeaderLogo));
But it fails saying:
System.Net.WebException : Could not find a part of the path 'C:\Images\HeaderLogo.png'.
From what I've read on Stack Overflow I shouldn't be using HttpContext.Current if I plan to unit test it, which is why I have tried using Path.Combine, but I'm unable to get that to work properly.
Can someone offer some guidance to what I need to do to get this unit test to work?
Thank you!
What I prefer to do when writing tests for code involving non-pure functions is to hide them behind, in simplest cases, plain old Func<string, string>:
class PromotionTrackerService
{
private readonly Func<string, string> imageMapper;
public PromotionTrackerService(Func<string, string> imageMapper)
{
this.imageMapper = imageMapper ?? HttpContext.Current.Server.MapPath;
}
public void GetProofOfPurchase()
{
var image = Image.GetInstance(imageMapper(GlobalConfig.HeaderLogo));
}
}
Now, your test does not look like a unit test -- it's more of an integration test, with all that file access and all.

How to structure my unit test?

I am new to unit test and wondering how to start testing. The application I am currently working on, does not have any unit test. It a winform application and I am only interested to test the data layer of this application.
Here is an example.
public interface ICalculateSomething
{
SomeOutout1 CalculateSomething1(SomeInput1 input1);
SomeOutout2 CalculateOSomething2(SomeInput2 input2);
}
public class CalculateSomething : ICalculateSomething
{
SomeOutout1 ICalculateSomething.CalculateSomething1(SomeInput1 input1)
{
SomeOutout1.Prop1 = calculateFromInput1(input1.Prop1, input1.Prop2);
SomeOutout1.Prop3 = calculateFromInput2(input1.Prop3, input1.Prop4);
return SomeOutout1;
}
SomeOutout2 ICalculateSomething.CalculateOSomething2(SomeInput2 input2)
{
SomeOutout2.Prop1 = calculateFromInput1(input2.Prop1, input2.Prop2);
SomeOutout2.Prop3 = calculateFromInput2(input2.Prop3, input2.Prop4);
return SomeOutout2;
}
}
I would like to test these two methods in the CalculateSomething. Those methods implementation are long and complicated. How should I structure my test?
I don't see a reason for not using a straight-forward unit test implementation. I'd start with a basic test method:
[TestMethod]
public void CalculateSomething1_FooInput
{
var input = new SomeInput1("Foo");
var expected = new SomeOutput1(...);
var calc = new CalculateSomething(...);
var actual = calc.CalculateSomething1(input);
Assert.AreEqual(expected.Prop1, actual.Prop1);
Assert.AreEqual(expected.Prop2, actual.Prop2);
Assert.AreEqual(expected.Prop3, actual.Prop3);
}
And then, as you add CalculateSomething1_BarInput and CalculateSomething2_FooInput, factor out some common code into helper methods:
[TestMethod]
public void CalculateSomething1_FooInput
{
var input = new SomeInput1("Foo");
var expected = new SomeOutput1(...);
var actual = CreateTestCalculateSomething().CalculateSomething1(input);
AssertSomeOutput1Equality(expected, actual);
}
As far as unit testing is concerned you would have to create the test methods for the functions that you want.
[TestMethod()]
public void CalculateSomething1()
{
// First we have to define the input for the fucntion
var input = new SomeInput1(); // Assumes your constructor creates the value for prop1 and prop2. Change as needed.
var classToBeTested = new CalculateSomething();
var output = classToBeTested(input);
// There are multiple ways to test if the outcome is correct choose the one that is correct for the method/output.
Assert.IsNotNull(output);
}
The method above would be in a unit test project and associated class file.
Some things to keep in mind when unit testing
Unit tests need to be independent
Long complicated code should be re-factored down into smaller units of code and tested.
Interfaces are an awesome way to remove dependencies. The use of interfaces allows concepts such as mocking. Mocking can be a little complicated at first so take your time when learning it. There are several mocking frameworks out there that can help a lot. i.e. RhinoMocks, Moq just to name a couple.
Those are explicitly implemented properties, so you have to use an interface reference to test them.
var input1 = new SomeInput1();
// setup required data in input1.
ICalculateSomething calculator = new CalculateSomething();
var output = calculator.CalculateSomething1(input1);
// Have assert statements on the properties of output to verify the calculation.
Don't use var for calculator, because that will give you a CalculateSomething reference and the interface methods are hidden.

MVC4 Unit test NSubstitute Could not find a call to return from

I have a MVC4 web application I'm unit testing right now. It uses entity framework for the database portion. I'm using NSubstitute to mock the database. This code is basically copied and pasted from another site which works fine, so I hope I'm just missing something super simple.
Thanks in advance!
Applications table in SQL:
AppID | ApplicationName
----------------------------
1 | MyCoolApplication
2 | MyOtherApplication
Entity created the Application class:
public class Application
{
public int AppID { get; set; }
public string ApplicationName { get; set; }
}
The mock section of the unit test looks like this:
var mockDb = Substitute.For<MyCoolApplicationsEntities>();
var applications = new List<Application>
{
new Application {AppID = 1, ApplicationName = "MyCoolApplication"},
new Application {AppID = 2, ApplicationName = "MyOtherApplication"},
};
var mockApplicationSet = Substitute.For<IDbSet<Application>, DbSet<Application>>();
mockApplicationSet.Provider.Returns(applications.AsQueryable().Provider);
mockApplicationSet.Expression.Returns(applications.AsQueryable().Expression);
mockApplicationSet.ElementType.Returns(applications.AsQueryable().ElementType);
mockApplicationSet.GetEnumerator().Returns(applications.AsQueryable().GetEnumerator());
mockApplicationSet.When(q => q.Add(Arg.Any<Application>()))
.Do(q => applications.Add(q.Arg<Application>()));
mockApplicationSet.When(q => q.Remove(Arg.Any<Application>()))
.Do(q => applications.Remove(q.Arg<Application>()));
mockDb.Applications.Returns(mockApplicationSet); //This is the line creating the error
The full error is:
Test method
MyProjectName.Controllers.MyControllerTest.TestOfSectionImTesting
threw exception:
NSubstitute.Exceptions.CouldNotSetReturnDueToNoLastCallException:
Could not find a 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);
But that doesn't work in my environment because Applications isn't a method. Like I said, this works fine in another site of mine, so it's got to be something basic I'm missing. Nothing I've found online has been helpful with my particular case. I updated to the newest version of NSubstitute and I uninstalled/reinstalled, but still have got nothing.
Again, thanks in advance!
NSubstitute can not mock non-virtual members. (There are quite a few caveats to substituting for classes.)
MyCoolApplicationsEntities.Applications will need to be virtual for .Returns() to work.
Here's what ended up working:
var context = Substitute.For<MyCoolApplicationsEntities>();
var applications = new List<Application>
{
new Application {AppID = 1, ApplicationName = "MyCoolApplication"}
};
var mockApplications = Substitute.For<DbSet<Application>, IQueryable<Application>>();
((IQueryable<Application>)mockApplications).Provider.Returns(applications.AsQueryable().Provider);
((IQueryable<Application>)mockApplications).Expression.Returns(applications.AsQueryable().Expression);
((IQueryable<Application>)mockApplications).ElementType.Returns(applications.AsQueryable().ElementType);
((IQueryable<Application>)mockApplications).GetEnumerator().Returns(applications.AsQueryable().GetEnumerator());
mockApplications.When(q => q.Add(Arg.Any<Application>()))
.Do(q => applications.Add(q.Arg<Application>()));
mockApplications.When(q => q.Remove(Arg.Any<Application>()))
.Do(q => applications.Remove(q.Arg<Application>()));
context.Applications = mockApplications;
I can't see you classes but you need to create interfaces with virtual members and have your code call the class by the interface, then you will be able to mock out the class.

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