How to unit test IValidatableObject Validate when it uses services for validation?

user_5868830 0
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My Validate method is accessing various services for validation. These services are dependency injected and can be accessed using the validationContext.GetService method. During runtime, this works fine.

public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
    var logic = (ShipRegistrationLogic)validationContext.GetService(typeof(ShipRegistrationLogic));
    var userManager = (UserManager<IdentityUser>)validationContext.GetService(typeof(UserManager<IdentityUser>));
    var spaceTransitAuthority = (SpaceTransitAuthority)validationContext.GetService(typeof(ISpaceTransitAuthority));
    var hull = logic.GetHull(HullId);
    var user = userManager.FindByIdAsync(UserId).Result;

    if (spaceTransitAuthority.CheckActualHullCapacity(hull) > logic.GetMaxAuthorizedMass(user))
    {
        yield return new ValidationResult("You do not have the required pilot's license for this hull.", new[] { nameof(HullId) });
    }
}

I would like to unit test this complex validation. However, during the execution of the test, I am unable to figure out how to access the services needed for testing the evaluation. As GetService returns null during the test run.

I am using Moq and xUnit, and I have tried mocking the GetService method of the ValidationContext without success, as ValidationContext is a sealed class and cannot be mocked.

This is the test which shows what I have tried:

[Theory]
[InlineData(1)]
[InlineData(2)]
[InlineData(3)]
public void Validate_ShouldPassMassCheck(int hullId)
{
    // Arrange
    var userId = _users[0].Id;
    var viewModel = new ShipRegistrationViewModel()
    {
        UserId = userId,
        HullId = hullId
    };

    var hull = new Hull()
    {
        DefaultMaximumTakeOffMass = TakeOffMassEnum.Tank,
        Id = hullId,
        Name = "Test"
    };

    var shipRegistrationLogicMock = new Mock<ShipRegistrationLogic>();
    var spaceTransitAuthorityMock = new Mock<ISpaceTransitAuthority>();
    shipRegistrationLogicMock.Setup(x => x.GetHull(hullId)).Returns(hull);
    shipRegistrationLogicMock.Setup(x => x.GetMaxAuthorizedMass(_users[0])).Returns((int)TakeOffMassEnum.Tank);
    _userManager.Setup(x => x.FindByNameAsync(userId))
        .ReturnsAsync(new IdentityUser()
        {
            UserName = "user",
        });

    spaceTransitAuthorityMock.Setup(x => x.CheckActualHullCapacity(hull)).Returns((double)TakeOffMassEnum.Tank);

    var context = new Mock<ValidationContext>(viewModel);
    context.Setup(x => x.GetService(typeof(ShipRegistrationLogic))).Returns(shipRegistrationLogicMock);
    context.Setup(x => x.GetService(typeof(UserManager<IdentityUser>))).Returns(_userManager);
    context.Setup(x => x.GetService(typeof(ISpaceTransitAuthority))).Returns(spaceTransitAuthorityMock);

    // Act
    var results = viewModel.Validate(context.Object);

    // Assert
    Assert.Single(results);
    Assert.Equal(ValidationResult.Success, results.First());
}
xunit.net moq unit-testing asp.net-mvc c#
2 Answers

You can mock a IServiceProvider and pass it in the constructor :

var services = new Mock<IServiceProvider>();
services.Setup(x => x.GetService(typeof(ShipRegistrationLogic)))
    .Returns(shipRegistrationLogicMock.Object);
services.Setup(x => x.GetService(typeof(UserManager<IdentityUser>)))
    .Returns(_userManager.Object);
services.Setup(x => x.GetService(typeof(ISpaceTransitAuthority)))
    .Returns(spaceTransitAuthorityMock.Object);

var context = new ValidationContext(viewModel, services.Object, null);

// Act
var results = viewModel.Validate(context);

You can also directly build a IServiceProvider without mock

user_27036730

As well as mocking IServiceProvider, like vernou says you can also build an IServiceProviver.

var services = new Microsoft.Extensions.DependencyInjection.ServiceCollection();
services.AddSingleton(_ => shipRegistrationLogicMock.Object);
services.AddSingleton<UserManager<IdentityUser>>(_ => _userManager.Object);
services.AddSingleton(_ => spaceTransitAuthorityMock.Object);
var serviceProvider = services.BuidServiceProvider();

// And finally
var context = new ValidationContext(viewModel, serviceProvider, null);
Patrick_McDonald_619890
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