I am trying to write some unit tests for a piece of logic which uses DbContext.
In my unit tests, I mock the dbContext and set the expectations.
At one place my code looks like this:
var myVar= await dbContext.Set<MyModel>().Where(.. some conditions..).FirstOrDefaultAsync();
I am mocking this dbContext and setting up as follows:
var myModelVar = new MyModel();
myModelVar.Id = Guid.NewGuid();
var myModelDbSet = new TestDbSet<MyModel>();
myModelDbSet .Add(myModelVar );
mockDbContext.Setup(dbContext => dbContext.Set<MyModel>()).Returns(myModelDbSet);
However, in the above location in the code, the unit test returns null.
Earlier in the code, I set another dbContext expectation which returns correct value in the unit test:
var anotherModelVar = new AnotherModel();
mockDbContext.Setup(dbContext => dbContext.Set<AnotherModel>()
.FindAsync(It.IsAny<object>()))
.Returns(Task.FromResult(anotherModelVar ));
I receive null value for the TestDbSet expectation and cannot understand the reason why could this be happening?
Related
I read a few tutorial on Moq C# package but I still can't really understand what is Setup and Returns in Moq.
Example,
mock.Setup(p => p.GetEmployeebyId(1)).ReturnsAsync("JK");
Example 2,
mock.Setup(x => x.Save(It.IsAny<DeskBooking>())).Callback<DeskBooking>(
deskBooking =>
{
savedDeskBooking = deskBooking;
});
)
TL;DR: Setup = When, Returns = What
Whenever you write unit tests then you want make sure that a given piece of functionality is working as expected. But most of the time the functionality depends on some other components / environment / external source / whatsoever.
To make your test focused and replayable we need to use test doubles. These will replace your dependencies during the test. We can categorize the test doubles like this:
Dummy: simple code that returns bogus data
Fake: a working alternative which can take shortcuts
Stub: custom logic with predefined data
Mock: custom logic with expectations (interactive stub)
Shim: custom logic at run-time (replace static with a delegate)
Spy: interceptors to record calls
So, whenever you want to create a mock then you have to tell that under what circumstances how should the component behave. In other words when the function is called with a particular input then what should be the expected output.
In case of Moq you can use the Setup to define the when. And the Returns to specify the what.
Here is a simple example. Let's suppose you have the following function:
private IService service;
string MyMethod()
{
int number = service.GetNextNumber();
if(number % 2 == 0)
{
return "even";
}
else
{
return "odd";
}
}
Then you can write the following to test cases:
public void GivenAnEvenNumber_WhenICallMyMethod_ThenItShouldReturnEven
{
//Arrange
var serviceMock = new Mock<IService>();
serviceMock
.Setup(svc => svc.GetNextNumber())
.Returns(2);
...
//Act
var result = SUT.MyMethod();
//Assert
Assert.Equal("even", result);
}
public void GivenAnOddNumber_WhenICallMyMethod_ThenItShouldReturnOdd
{
//Arrange
var serviceMock = new Mock<IService>();
serviceMock
.Setup(svc => svc.GetNextNumber())
.Returns(1);
...
//Act
var result = SUT.MyMethod();
//Assert
Assert.Equal("odd", result);
}
So, as you can see we have used Setup and Returns to direct the control flow in each test case.
Your second example can be considered a Spy, because there you are recording the input for latter assessment.
In example 1
mock.Setup(p => p.GetEmployeebyId(1)).ReturnsAsync("JK");
sets up your mock so when GetEmployeebyId is called with a 1 as the parameter, the mock will return "JK".
In example 2
mock.Setup(x => x.Save(It.IsAny<DeskBooking>())).Callback<DeskBooking>(
deskBooking =>
{
savedDeskBooking = deskBooking;
});
when the Save method is called with any parameter of type DeskBooking, the lambda function will save the parameter in the savedDeskBooking variable. You can then test that you've saved the DeskBooking you expected.
trying to mock one method in repository which having return IQueryable.
Please see the unit test method
[Fact]
public void TestMethod()
{
var mockZonal = new Mock<IBaseRepository<ZonalDefinition>>().SetupAllProperties();
var list = new List<ZonalDefinition>() { new ZonalDefinition() { DestinationZone = "401" } }.AsQueryable();
mockZonal.Setup(r => r.GetQueryableFromSql<ZonalDefinition>(new SqlQuerySpec(), new FeedOptions())).Returns(()=>list);
_repoFactory.Setup(r => r.GetGenericRepository<ZonalDefinition>(It.IsAny<string>(), It.IsAny<string>())).Returns(mockZonal.Object);
var afShipmentDetail = new AirFreightShipmentDetail();
var response = _quoteRespository.SetCXShipmentTargetValue(afShipmentDetail);
Assert.NotNull(response);
}
while executing the test am getting the result for mocked method 'GetQueryableFromSql' as 'Enumeration yielded no results'
enter image description here
As far as I understand Moq, you have to setup your method differently:
mockZonal.Setup(r => r.GetQueryableFromSql<ZonalDefinition>(It.IsAny<SqlQuerySpec>(),
It.IsAny<FeedOptions>()))
.Returns(()=>list);
The way you set it up, it would only match if those exact objects were passed to the method (which they won't).
If you need to be more specific with regards to the parameters to match, have a look at the documentation.
I'm writing a data access layer for my application and trying to mock out the CosmosDB SDK dependency for unit testing. I am using NUnit with NSubstitute and have come across the issue where I am trying to mock the return values for Container.GetItemQueryIterator.
I have successfully provided a mock feedIterator as a response for that call and a mock feedResponse as a return value for feedIterator.ReadNextAsync, but I cannot figure out how to inject any sort of values into the FeedResponse to test against
The code I'm trying to test looks like this:
var feedIterator = container.GetItemQueryIterator<T>(queryDefinition);
while (feedIterator.HasMoreResults){
result.success = true;
foreach (var item in await feedIterator.ReadNextAsync()){
list.Add(item);
}
}
My attempt at mocking out the dependencies like this (Simplified):
this.mockFeedResponse = Substitute.For<FeedResponse<T>>(this.mockApplicationList);
this.mockFeedIterator = Substitute.For<FeedIterator<T>>();
this.mockFeedIterator.ReadNextAsync().ReturnsForAnyArgs(Task.FromResult(this.mockFeedResponse));
this.mockFeedIterator.HasMoreResults.Returns(true);
Looking at the AzureCosmosDB SDK documentation, there seems to be a FeedResponse constructor for mocking that takes an IEnumerable as a parameter, but NSubstitute complains telling me it can't find this constructor when I attempt to pass in a list to use. Is there an alternative that I can feed some IEnumerable as a FeedResponse? Where am I going wrong?
I also managed the issue by mocking the GetEnumerator call on the FeedResponse mock. However, something to keep in mind is that if you just set mockFeedIterator.HasMoreResults(true), you'll end up in an infinite loop.
I solved that problem by using Moq's Callback method feature. I configured the HasMoreResults method to return true, and then setup a callback on the ReadNextAsync method to reconfigure HasMoreResults to return false. That way, it will drop into the while loop the first time, populate the return collection based on the mocked GetEnumerator method, and then exit the loop and return that collection to the test method.
var myItems = new List<MyItem>
{
new MyItem(),
new MyItem()
};
var feedResponseMock = new Mock<FeedResponse<MyItem>>();
feedResponseMock.Setup(x => x.GetEnumerator()).Returns(myItems.GetEnumerator());
var feedIteratorMock = new Mock<FeedIterator<MyItem>>();
feedIteratorMock.Setup(f => f.HasMoreResults).Returns(true);
feedIteratorMock
.Setup(f => f.ReadNextAsync(It.IsAny<CancellationToken>()))
.ReturnsAsync(feedResponseMock.Object)
.Callback(() => feedIteratorMock
.Setup(f => f.HasMoreResults)
.Returns(false));
var containerMock = new Mock<Container>();
containerMock
.Setup(c => c.GetItemQueryIterator<MyItem>(
It.IsAny<QueryDefinition>(),
It.IsAny<string>(),
It.IsAny<QueryRequestOptions>()))
.Returns(feedIteratorMock.Object);
You can mock ReadNextAsync to return a mock of FeedResponse that only has GetEnumerator() defined. The GetEnumerator of the List you create will then be passed through to the underlying implementation of the foreach.
The following example uses Moq, but you should be able to do something similar in your implementation.
var mockFeedResponse = new Mock<FeedResponse<Thing>>();
mockFeedResponse
.Setup(x => x.GetEnumerator())
.Returns(
new List<Thing>
{
new Thing(),
new Thing()
}.GetEnumerator()
);
For what it's worth - I worked around this by changing my code to access the Resource field on the FeedResponse received from CosmosDB. In my tests, I was able to then mock the return value for Resource and get the desired result.
I'm going to simplify a bit the problem:
In my tests, I use a mocked object (I mocked it because it calls a bdd) which I give in parameters to a method of another object (not mocked) whose purpose is to modify a property of this mocked object.
ModifyingClass myModifyingClass = new ModifyingClass();
Mock<ToModifyClass> mockedClass = new Mock<ToModifyClass>();
mockedClass.Setup(mc => mc.name).Returns("Test1");
myModifyingClass.modify(mockedClass.Object);
The method modify then try to set the property name of the mocked object, but it won't work, so maybe it's the normal behavior but I really need to test if all of this work and if the method modify set the property as I want.
As mentioned in the comments you need to setup the mocked class differently in order to retain the values passed to properties.
Reference Moq - Quickstart
Stub all properties on a mock (not available on Silverlight):
mock.SetupAllProperties();
The example test provided would then look like...
//Arrange
var myModifyingClass = new ModifyingClass();
var mockedClass = new Mock<ToModifyClass>();
mockedClass.SetupAllProperties(); //<-- this will allow property changes to be retained.
var model = mockedClass.Object;
//set the property now that it can be set
model.name = "Test1";
var expected = "expected value here";
//Act
myModifyingClass.modify(model);
//Assert
var actual = model.name;
Assert.AreEqual(expected, actual);
//... other assertions
In Moq one would need to setup the getter.
mockedClass.SetupGet(mc => mc.name).Returns("Test1");
I am writing unit tests using Moq. I have created a mock object. Now when i try to mock its property i am getting error "An expression tree may not contain an indexed property"
here is my code.
public Node GetNode(IMyInterface interface, string itemName)
{
return interface.Items[itemName];
}
Here is the unit test
var expected = new Node();
var itemName = "TestName";
var mock = new Mock<IMyInterface>();
mock.Setup(f => f.Items[itemName]).Returns(expected);
var target = new MyClass();
var actual = target.GetNode(mock.Object, itemName);
Assert.AreEqual(expected, actual);
This line is giving me error.
mock.Setup(f => f.Items[itemName]).Returns(expected);
How can i moq this function.
Interface was a COM object and there were get function, so instead of directly accessing property using indexer use get function,
mock.Setup(f => f.get_Items(itemName)).Returns(expected);
Using Moq in ASP.NET Core 2.2, the get_Items setup does not work. But this does:
Mock<IConfiguration> configuration = new Mock<IConfiguration>();
configuration.Setup(x => x[key]).Returns(value);