.NET Core Unit Testing - Mock IOptions

Question

I feel like I\'m missing something really obvious here. I have classes that require injecting of options using the .NET Core IOptions pattern(?). When I unit te

Answer 1

Given class Person that depends on PersonSettings as follows:

public class PersonSettings
{
    public string Name;
}

public class Person
{
    PersonSettings _settings;

    public Person(IOptions settings)
    {
        _settings = settings.Value;
    }

    public string Name => _settings.Name;
}

IOptions can be mocked and Person can be tested as follows:

[TestFixture]
public class Test
{
    ServiceProvider _provider;

    [OneTimeSetUp]
    public void Setup()
    {
        var services = new ServiceCollection();
        // mock PersonSettings
        services.AddTransient>(
            provider => Options.Create(new PersonSettings
            {
                Name = "Matt"
            }));
        _provider = services.BuildServiceProvider();
    }

    [Test]
    public void TestName()
    {
        IOptions options = _provider.GetService>();
        Assert.IsNotNull(options, "options could not be created");

        Person person = new Person(options);
        Assert.IsTrue(person.Name == "Matt", "person is not Matt");    
    }
}

To inject IOptions into Person instead of passing it explicitly to the ctor, use this code:

[TestFixture]
public class Test
{
    ServiceProvider _provider;

    [OneTimeSetUp]
    public void Setup()
    {
        var services = new ServiceCollection();
        services.AddTransient>(
            provider => Options.Create(new PersonSettings
            {
                Name = "Matt"
            }));
        services.AddTransient();
        _provider = services.BuildServiceProvider();
    }

    [Test]
    public void TestName()
    {
        Person person = _provider.GetService();
        Assert.IsNotNull(person, "person could not be created");

        Assert.IsTrue(person.Name == "Matt", "person is not Matt");
    }
}