Autofac.Extras.NSubstitute

NSubstitute auto mocking integration for Autofac Autofac IoC.

Getting Started

Given you have a system under test and a dependency:

public class SystemUnderTest
{
  public SystemUnderTest(IDependency dependency)
  {
  }
}

public interface IDependency
{
}

Use the Autofac.Extras.NSubstitute package's AutoSubstitute class to instantiate the system under test.

[Test]
public void Test()
{
  using (var autoSub = new AutoSubstitute())
  {
    // The AutoSubstitute class will inject a mock IDependency
    // into the SystemUnderTest constructor
    var sut = autoSub.Resolve<SystemUnderTest>();
  }
}

Configuring Mocks

[Test]
public void Test()
{
  using (var autoSub = new AutoSubstitute())
  {
    // Arrange
    autoSub.Resolve<IDependency>().GetValue().Returns("expected value");
    var sut = autoSub.Resolve<SystemUnderTest>();

    // Act
    var actual = sut.DoWork();

    // Assert
    autoSub.Resolve<IDependency>().Received().GetValue();
    Assert.AreEqual("expected value", actual);
  }
}

public class SystemUnderTest
{
  private readonly IDependency dependency;

  public SystemUnderTest(IDependency strings)
  {
    this.dependency = strings;
  }

  public string DoWork()
  {
    return this.dependency.GetValue();
  }
}

public interface IDependency
{
  string GetValue();
}

Configuring Specific Dependencies

You can configure the AutoSubstitute to provide a specific instance for a given service type:

[Test]
public void Test()
{
  using (var autoSub = AutoSubstitute())
  {
    var dependency = new Dependency();
    autoSub.Provide<IDependency>(dependency);

    // ...and the rest of the test.
  }
}

Partial subs

[Test]
public void Test()
{
  using (var autoSub = AutoSubstitute())
  {
    var dependency = Substitute.ForPartsOf<Dependency>();
    dependency.When(x => x.GetValue()).DoNotCallBase();
    dependency.GetValue().Returns("1,2,3");
    autoSub.Provide<IDependency>(dependency);

    // ...and the rest of the test.
  }
}

Or you can use the built in one

[Test]
public void Test()
{
  using (var autoSub = AutoSubstitute())
  {
    var dependency = autoSub.ProvidePartsOf<IDependency, Dependency>();
    dependency.When(x => x.GetValue()).DoNotCallBase();
    dependency.GetValue().Returns("1,2,3");

    // ...and the rest of the test.
  }
}