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Unit test - check on Empty

I developed Unit test for my service. Now my test check on inserting Name and 2nd check on a null.
[TestMethod]
public async Task InsertTownName_ReturnTownName()
{
var builder = new RepositoryBuilder<TownRepository>().SetupManager();
using (builder.CreateIsolationScope())
{
var repository = builder.Build();
var townName = "Town" + DateTime.UtcNow.ToString();
await repository.InsertTown(townName);
var connection = builder.TransactionManager.Connection;
var transaction = builder.TransactionManager.Transaction;
var result = await connection.ReadSingleOrDefaultAsync<Town>(x => x.Name == townName, transaction: transaction);
Assert.IsNotNull(result);
Assert.AreEqual(townName, result.Name);
}
}
[TestMethod]
public async Task InsertNullName()
{
var builder = new RepositoryBuilder<TownRepository>().SetupManager();
using (builder.CreateIsolationScope())
{
var repository = builder.Build();
await repository.InsertTown(null);
var connection = builder.TransactionManager.Connection;
var transaction = builder.TransactionManager.Transaction;
var result = await connection.ReadSingleOrDefaultAsync<Town>(x => x.Name == null, transaction: transaction);
Assert.IsNull(result.Name);
Assert.AreEqual(null, result.Name);
}
}
Both of this method works good. Next step I need check on Empty (If in line where user need insert town name - empty name). I have no idea how implement it. Could You recommend to me and could you check 2nd method for working with null. Is it correct unit test? Here my method that I tested
public async Task<int> InsertTown(string townName)
if (String.IsNullOrEmpty(townName))
{
throw new Exception();
}
else
{
var parameters = new { townName };
return await Connection.QueryFirstOrDefaultAsync<int>(Adhoc["AddTown"], parameters, Transaction);
}

Here is an example of what a method with input parameters checking might look like.
public async Task<int> InsertTown(string townName)
{
if (townName == null)
{
throw new ArgumentNullException(nameof(townName));
}
if (string.IsNullOrWhiteSpace(townName))
{
throw new ArgumentException("Parameter cannot be empty", nameof(townName));
}
var parameters = new { townName };
//return await Connection.QueryFirstOrDefaultAsync<int>(Adhoc["AddTown"], parameters, Transaction);
return await Task.Run(() => 42); // for testing puprposes
}
You can test it like this
[TestMethod]
public async Task InsertTown_NullString_ThrowsArgumentNullExceptionAsync()
{
string townName = null;
// var repository = ...;
await Assert.ThrowsExceptionAsync<ArgumentNullException>(() =>
repository.InsertTown(townName));
}
[DataTestMethod]
[DataRow("")]
[DataRow(" ")]
public async Task InsertTown_EmptyString_ThrowsArgumentExceptionAsync(string value)
{
string townName = value;
// var repository = ...;
await Assert.ThrowsExceptionAsync<ArgumentException>(() =>
repository.InsertTown(townName));
}
As mentioned in the comments, it looks like your unit tests are more like integration tests.
In unit tests, you should not access neither real database, work with a network, nor work with a file system.
You have to mock any dependencies. For example with NSubstitute, FakeItEasy or Moq.
Your Connection.QueryFirstOrDefaultAsync method is static, right?
It is highly recommendable to rewrite the code, getting rid of static methods. With the extraction of abstractions to interfaces. Because static methods, like in your case, are untested or difficult to test.

Assert an Exception using XUnit

I am a newbie to XUnit and Moq. I have a method which takes string as an argument.How to handle an exception using XUnit.
[Fact]
public void ProfileRepository_GetSettingsForUserIDWithInvalidArguments_ThrowsArgumentException() {
//arrange
ProfileRepository profiles = new ProfileRepository();
//act
var result = profiles.GetSettingsForUserID("");
//assert
//The below statement is not working as expected.
Assert.Throws<ArgumentException>(() => profiles.GetSettingsForUserID(""));
}
Method under test
public IEnumerable<Setting> GetSettingsForUserID(string userid)
{
if (string.IsNullOrWhiteSpace(userid)) throw new ArgumentException("User Id Cannot be null");
var s = profiles.Where(e => e.UserID == userid).SelectMany(e => e.Settings);
return s;
}

The Assert.Throws expression will catch the exception and assert the type. You are however calling the method under test outside of the assert expression and thus failing the test case.
[Fact]
public void ProfileRepository_GetSettingsForUserIDWithInvalidArguments_ThrowsArgumentException()
{
//arrange
ProfileRepository profiles = new ProfileRepository();
// act & assert
Assert.Throws<ArgumentException>(() => profiles.GetSettingsForUserID(""));
}
If bent on following AAA you can extract the action into its own variable.
[Fact]
public void ProfileRepository_GetSettingsForUserIDWithInvalidArguments_ThrowsArgumentException()
{
//arrange
ProfileRepository profiles = new ProfileRepository();
//act
Action act = () => profiles.GetSettingsForUserID("");
//assert
ArgumentException exception = Assert.Throws<ArgumentException>(act);
//The thrown exception can be used for even more detailed assertions.
Assert.Equal("expected error message here", exception.Message);
}
Note how the exception can also be used for more detailed assertions
If testing asynchronously, Assert.ThrowsAsync follows similarly to the previously given example, except that the assertion should be awaited,
public async Task Some_Async_Test() {
//...
//Act
Func<Task> act = () => subject.SomeMethodAsync();
//Assert
var exception = await Assert.ThrowsAsync<InvalidOperationException>(act);
//...
}

If you do want to be rigid about AAA then you can use Record.Exception from xUnit to capture the Exception in your Act stage.
You can then make assertions based on the captured exception in the Assert stage.
An example of this can be seen in xUnits tests.
[Fact]
public void Exception()
{
Action testCode = () => { throw new InvalidOperationException(); };
var ex = Record.Exception(testCode);
Assert.NotNull(ex);
Assert.IsType<InvalidOperationException>(ex);
}
It's up to you what path you want to follow, and both paths are fully supported by what xUnit provides.

You could consider something like this if you want to stick to AAA:
// Act
Task act() => handler.Handle(request);
// Assert
await Assert.ThrowsAsync<MyExpectedException>(act);

I think there are two way to handle this scenario which I personally like. Suppose I have below method which I want to test
public class SampleCode
{
public void GetSettingsForUserID(string userid)
{
if (string.IsNullOrWhiteSpace(userid)) throw new ArgumentException("User Id
Cannot be null");
// Some code
}
}
I can test this with below testcase,Make sure you add FluentAssertions nuget in your test project.
public class SampleTest
{
private SampleCode _sut;
public SampleTest()
{
_sut = new SampleCode();
}
[Theory]
[InlineData(null)]
[InlineData(" ")]
public void TestIfValueIsNullorwhiteSpace(string userId)
{
//Act
Action act= ()=> _sut.GetSettingsForUserID(userId);
// Assert
act.Should().ThrowExactly<ArgumentException>().WithMessage("User Id Cannot be null");
}
}
but I found one problem here, whitespace and Null are two different things.
c# provides ArgumentException for whitespace and ArgumentNullException for null reference.
So You can refactor your code something like this
public void GetSettingsForUserID(string userid)
{
Guard.Against.NullOrWhiteSpace(userid, nameof(userid));
}
Here you need Ardalis.GuardClauses nuget in your code project And testcase will be something like this
[Fact]
public void TestIfValueIsNull()
{
//Act
Action act = () => _sut.GetSettingsForUserID(null);
//Assert
act.Should().ThrowExactly<ArgumentNullException>().WithMessage("*userId*");
}
[Fact]
public void TestIfValueIsWhiteSpace()
{
//Act
Action act= ()=> _sut.GetSettingsForUserID(" ");
//Assert
act.Should().ThrowExactly<ArgumentException>().WithMessage("*userId*");
}

Instead of following complicated protocols I found it most convenient to use a try catch block :
try
{
var output = Settings.GetResultFromIActionResult<int>(controller.CreateAllFromExternalAPI());
Assert.True(output > 0);
}
catch(InvalidOperationException e)
{
Assert.True("Country table can only be filled from ExternalAPI if table is blank"==e.Message);
}

C# How to Moq entityframework DbSet Add method

I am trying to create a test to test entity framework Add method. Can anyone help how to mock the DbSet.Add method. I have tried as below but not working. What am I doing wrong?
The result I am getting is null after repository.Insert...
Test.cs:
var productToCreate = new Product { Name = "Added", Description = "Added" };
var result = repository.InsertAsync(objToCreate, userContext).Result;
Assert.AreEqual(result.Name, "Added");
Mock.cs
internal static DbSet<T> GetMockedDataSet<T>(IEnumerable<T> data) where T : class
{
// Create a mocked data set that contains the data
var set = new Mock<DbSet<T>>();
set.As<IDbAsyncEnumerable<T>>()
.Setup(m => m.GetAsyncEnumerator())
.Returns(new TestDbAsyncEnumerator<T>(data.GetEnumerator()));
set.As<IQueryable<T>>()
.Setup(m => m.Provider)
.Returns(new TestDbAsyncQueryProvider<T>(data.AsQueryable().Provider));
set.As<IQueryable<T>>().Setup(m => m.Expression).Returns(data.AsQueryable().Expression);
set.As<IQueryable<T>>().Setup(m => m.ElementType).Returns(data.AsQueryable().ElementType);
set.As<IQueryable<T>>().Setup(m => m.GetEnumerator()).Returns(data.GetEnumerator());
set.Setup(x => x.AsNoTracking()).Returns(set.Object);
set.Setup(x => x.Add(It.IsAny<T>())).Callback<T>((s) => data.Concat(new[] { s }));
// Return the mock
return set.Object;
}
Repository:
public async Task<Product> InsertAsync(Product input)
{
using (var ctx = .....))
{
var added = ctx.Set<Product>().Add(input);
await ctx.ValidateAndSaveAsync();
return added;
}
}

According to how the Add method is being used in the method under test...
var added = ctx.Set<Product>().Add(input);
...there should also be a Returns in the setup that returns the argument that was entered, if that is the desired functionality.
set.Setup(x => x.Add(It.IsAny<T>()))
.Returns<T>(arg => arg)
.Callback<T>((s) => data.Concat(new[] { s }));
But given that the information about context dependency is unknown...
using (var ctx = .....))
It is uncertain if the provided solution will have the desired effect.
Additionally if testing an async method, don't mix async and sync calls. The following line...
var result = repository.InsertAsync(objToCreate, userContext).Result;
...can cause deadlocks.
Make the test method async all the way.
[TestMethod]
public async Task InsertAsync_Should_Return_Product() {
//...other code
var expected = new Product { Name = "Added", Description = "Added" };
var actual = await repository.InsertAsync(expected, userContext);
Assert.AreEqual(expected.Name, actual.Name);
}

How to moq Entity Framework SaveChangesAsync?

Mock<IDbContext> dbContext;
[TestFixtureSetUp]
public void SetupDbContext()
{
dbContext = new Mock<IDbContext>();
dbContext.Setup(c => c.SaveChanges()).Verifiable();
dbContext.Setup(c => c.SaveChangesAsync()).Verifiable();
dbContext.Setup(c => c.Customers.Add(It.IsAny<Customer>()))
.Returns(It.IsAny<Customer>()).Verifiable();
}
[Test]
public async Task AddCustomerAsync()
{
//Arrange
var repository = new EntityFrameworkRepository(dbContext.Object);
var customer = new Customer() { FirstName = "Larry", LastName = "Hughes" };
//Act
await repository.AddCustomerAsync(customer);
//Assert
dbContext.Verify(c => c.Customers.Add(It.IsAny<Customer>()));
dbContext.Verify(c => c.SaveChangesAsync());
}
[Test]
public void AddCustomer()
{
//Arrange
var repository = new EntityFrameworkRepository(dbContext.Object);
var customer = new Customer() { FirstName = "Larry", LastName = "Hughes" };
//Act
repository.AddCustomer(customer);
//Assert
dbContext.Verify(c => c.Customers.Add(It.IsAny<Customer>()));
dbContext.Verify(c => c.SaveChanges());
}
And here's what I want to test:
public class EntityFrameworkRepository
{
private readonly IDbContext DBContext;
public EntityFrameworkRepository(IDbContext context)
{
DBContext = context;
}
public async Task AddCustomerAsync(Customer customer)
{
DBContext.Customers.Add(customer);
await DBContext.SaveChangesAsync();
}
public void AddCustomer(Customer customer)
{
DBContext.Customers.Add(customer);
DBContext.SaveChanges();
}
}
AddCustomers test passes.
AddCustomersAsync test fails, I keep getting a NullReferenceException after calling await DbContext.SaveChangesAsync().
at
MasonOgCRM.DataAccess.EF.EntityFrameworkRepository.d__2.MoveNext()
in
C:\Users\Mason\Desktop\Repositories\masonogcrm\src\DataAccess.EFRepository\EntityFrameworkRepository.cs:line
43
I can't see anything that's null in my code. DbContext is not null. The equivalent test of AddCustomers which is identical with the exception of not being async runs as expected. I suspect I haven't performed a correct setup of SaveChangesAsync in SetupDBContext() but I don't know what to do to fix it.

You are right the problem occurs because one of your setups incorrect :: dbContext.Setup(c => c.SaveChangesAsync()).Verifiable();.
The method return a Task and you forgot to return a Task therefore null returns.
You can remove dbContext.Setup(c => c.SaveChangesAsync()).Verifiable(); or
change the setup to something like:
dbContext.Setup(c => c.SaveChangesAsync()).Returns(() => Task.Run(() =>{})).Verifiable();

You could use
dataContext.Setup(x => x.SaveChangesAsync()).ReturnsAsync(1);
and
dataContext.Verify(x=>x.SaveChangesAsync());

This worked for me:
dbContext.Verify(m => m.SaveChangesAsync(It.IsAny<CancellationToken>()), Times.Once());

It may also require a cancellation token, so something like this should work:
dataContext.Setup(x => x.SaveChangesAsync(It.IsAny<CancellationToken>())).ReturnsAsync(1);

ASP.NET MVC WebAPI create ViewModel from async tasks

I write web application using ASP.NET MVC WebAPI and I want to transform current synchronous code to asynchronous for optimization. Problem is that I fill ViewModel with multiple objects taken from repository. These calls from repository should be async.
Let's asume I have signature for repository calls respecting this interface
public interface ICompanyRepository
{
IEnumerable<Company> GetCompanies();
IEnumerable<Address> GetAddresses();
}
ViewModels definition
public class CompaniesFullViewModel
{
public IEnumerable<Company> Companies { get; set; }
public IEnumerable<Address> Addresses { get; set; }
}
And controller:
public class CompanyController
{
public readonly ICompanyRepository Repository { get; private set; }
public CompanyController(IRepository repository)
{
Repository = repository;
}
[ResponseType(typeof(CompaniesFullViewModel))]
public HttpResponseMessage Get()
{
var companies = Repository.GetCompanies();
var addresses = Repository.GetAddresses();
HttpStatusCode statusCode = companies.Any()
? HttpStatusCode.OK
: HttpStatusCode.PartialContent;
return
Request.CreateResponse(
statusCode,
new CompaniesFullViewModel
{
Companies = companies,
Addresses = addresses
});
}
}
Furthermore I have tests implemented to the controller:
[TestClass]
public sealed class CompanyTestController : BaseTestController
{
#region Fields
private static Mock<ICompanyRepository> _repositoryMock;
private static CompanyController _controller;
#endregion
[ClassInitialize]
public static void Initialize(TestContext testContext)
{
// Mock repository
_repositoryMock = new Mock<ICompanyRepository>();
DependencyResolver.Default.Container.RegisterInstance(_repositoryMock.Object);
// Create controller
_controller =
DependencyResolver.Default.Container.Resolve<CompanyController>();
// Init request
_controller.Request = new HttpRequestMessage();
_controller.Request.SetConfiguration(new HttpConfiguration());
}
[ClassCleanup]
public static void Cleanup()
{
_controller.Dispose();
}
[TestMethod]
public void Get_ActionExecutes_ReturnsEmptyCompaniesViewModel()
{
var companies = new List<Company>();
var addresses = new List<Address>();
// Setup fake method
_repositoryMock
.Setup(c => c.GetCompanies())
.Returns(companies);
_repositoryMock
.Setup(c => c.GetAddresses())
.Returns(addresses);
// Execute action
var response = _controller.Get();
// Check the response
Assert.AreEqual(HttpStatusCode.PartialContent, response.StatusCode);
}
}
How can I convert the controller to async, if the repository is async and the signature looks like this:
public interface ICompanyRepository
{
Task<IEnumerable<Company>> GetCompaniesAsync();
Task<IEnumerable<Address>> GetAddressesAsync();
}

What you need to do is change the Controller action to be async as well, and change the return type to Task<>. You can then await your asynchronous repository calls:
[ResponseType(typeof(CompaniesFullViewModel))]
public async Task<HttpResponseMessage> Get() // async keyword.
{
var companies = await Repository.GetCompaniesAsync(); // await
var addresses = await Repository.GetAddressesAsync(); // await
HttpStatusCode statusCode = companies.Any()
? HttpStatusCode.OK
: HttpStatusCode.PartialContent;
return
Request.CreateResponse(
statusCode,
new CompaniesFullViewModel
{
Companies = companies,
Addresses = addresses
});
}
By convention, you can also change the name of the controller action to end in Async as well, although if you are using RESTful conventions and / or Routing attributes, the actual name of the controller action isn't really important.
Testing
I use XUnit and NUnit, but it seems MSTest also supports testing of asynchronous methods, and Moq also provides Async versions of the setups:
[Test]
public async Task Get_ActionExecutes_ReturnsEmptyCompaniesViewModel() // async Task
{
var companies = new List<Company>();
var addresses = new List<Address>();
// Setup fake method
_repositoryMock
.Setup(c => c.GetCompaniesAsync())
.ReturnsAsync(companies); // Async
_repositoryMock
.Setup(c => c.GetAddressesAsync())
.ReturnsAsync(addresses); // Async
// Execute action
var response = await _controller.Get(); // Await
// Check the response
Assert.AreEqual(HttpStatusCode.PartialContent, response.StatusCode);
_repositoryMock.Verify(m => m.GetAddressesAsync(), Times.Once);
_repositoryMock.Verify(m => m.GetCompaniesAsync(), Times.Once);
}
As an aside, it seems you are using Setter Dependency injection. An alternative is to use Constructor injection, which has the benefit of ensuring that the class is always in a valid state (i.e. there is no transient state while it is waiting for the dependencies to be set). This also allows the dependencies (your repository in this case) to be made readonly.