ChainFlow.TestKit 1.0.0

ChainFlow TestKit

A test kit for ChainFlow Workflows built on top of Moq (Sponsorlink-free version 4.20.69). This library will make testing of Workflows a breeze.

The usage is quite simple. Given a class injects an IChainFlowBuilder,the testKit can create a conctrete instance of the builder with all required dependencies needed to build the specified Workflow. The entry point of the TestKit is the Container class:

Container container = new();

This container uses a fair simple rule. It scans, recursively, all constructors for the IChainFlows declared in the Workflow and it will register:

• if a class is found, a concrete instance of that class
• if an interface is found, a Mock<TInterface> for that instance

Moreover, all registered Mock<TInterface> can be retrieved for further customization of the flow to be tested using method:

Mock<IMockedDependency> dependency = container.GetMock<IMockedDependency>();

This can be achieved with the inizialization method:

Container container = new();
IChainFlowBuilder builder = container.GetChainFlowBuilder((x) => new FakeWorkflow(x));
FakeWorkflow workflow = new(builder);

To ease developer experience, as long as a dependency returns an OperationResult<T> or a bool, the TestKit Container will return automatically a success result with a concrete instance of the declared type, so even complex flows can be tested in minutes.

After Worklow's ProcessAsync() method is executed in the test run, it can be checked which IChainFlows were invoked by leveraging the following method:

container.VerifyWorkflowCallStack(new ChainFlowStack[]{});

The ChainFlowStack class is a wrapper used to point to a specific IChainFlow registration. The stack returned by the Container mantains the sequence in which IChainFlows have been processed, giving an exact view of the internal flow. This class has 2 constructors, that match quite precisely the way an IChainFlow is registered in DI:

public ChainFlowStack(Type flowType);
public ChainFlowStack(Type flowType, string flowTag);

The second constructor, as per DI extension methods, is inteded to be used when multiple registration for the same IChainFlow type exists.

Here's a full example:

[Fact]
public async Task ProcessAsync_WhenMockIsSetupForFailure_ReturnsFailure()
{
    //Arrange
    Container container = new();
    IChainFlowBuilder builder = container.GetChainFlowBuilder((x) => new FakeWorkflow(x));
    FakeWorkflow workflow = new(builder);

    container.GetMock<IFakeDependency>()
        .Setup(x => x.ProcessAsync(It.IsAny<RequestToProcess>(), It.IsAny<CancellationToken>()))
        .ReturnsAsync(OperationResult<bool>.CreateWithFailure(false, string.Empty));

    //Act
    var result = await workflow.ProcessAsync(new RequestToProcess(new Input { Id = 1, Value = "abc" }), CancellationToken.None);

    //Assert
    result.Outcome.Should().Be(FlowOutcome.Success);
    container.VerifyWorkflowCallStack(new ChainFlowStack[]
    {
        new (typeof(DataValidatorFlow<Input>)),
        new (typeof(DataMapperFlow<Input, InputEnriched>)),
        new (typeof(StorageReaderFlow<InputEnriched, InputEnriched>)),
        new (typeof(InputFlowDispatcher)),
        new (typeof(StorageRemoverFlow<InputEnriched>)),
    });
}