@fluidframework/test-utils

This package contains utilities for writing end-to-end tests in Fluid Framework. It helps in the creation of a simple hosting application to test Fluid objects and other functionalities of the system.

Local Code Loader

LocalCodeLoader in localCodeLoader.ts is a simple code loader that can load a Fluid package with a given entry point. It can be used to load multiple different Fluid packages with different sources (IFluidCodeDetails).

It should be created by passing in a list of source to entry point mapping. Then entry point can be an IFluidDataStoreFactory, IRuntimeFactory or a fluidExport:

// The fluidEntryPoint type.
export type fluidEntryPoint = Partial<IProvideRuntimeFactory & IProvideFluidDataStoreFactory & IFluidModule>;

// Constructor for LocalCodeLoader.
constructor(packageEntries: Iterable<[IFluidCodeDetails, fluidEntryPoint]>);

On load, it retrieves the fluidEntryPoint matching the package in the IFluidCodeDetails and loads it.

Local Loader

localLoader.ts contains couple of methods:

createLocalLoader

This method creates a simple Loader that can be used to resolve a Container or request a Fluid object.

It should be created with a list of source to entry point mappings (of type fluidEntryPoint as explained in LocalCodeLoader section above), an ILocalDeltaConnectionServer and an IUrlResolver:

export function createLocalLoader(
    packageEntries: Iterable<[
        IFluidCodeDetails,
        Partial<IProvideRuntimeFactory & IProvideFluidDataStoreFactory & IFluidModule>
    ]>,
    deltaConnectionServer: ILocalDeltaConnectionServer,
    urlResolver: IUrlResolver,
): ILoader;

• It creates a LocalCodeLoader using the fluidEntryPoint list to load Container code.
• It creates a DocumentServiceFactory which serves as the driver layer between the container and the server.

createAndAttachContainer

This method creates and attaches a Container with the given source and an attachRequest. An ILoader should also be passed in that will be used to load the Container. The attachRequest format varies per url resolver. Most resolvers have helper methods for creating attach requests. You should use the helper method on the url resolver passed to the loader to generate the attachRequest:

export async function createAndAttachContainer(
    source: IFluidCodeDetails,
    loader: ILoader,
    attachRequest: IRequest,
): Promise<IContainer>

The usual flow is to create a LocalLoader by calling createLocalLoader and then using it to call createAndAttachContainer. However, this should work with any ILoader.

Test Fluid Object

testFluidObject.ts provides TestFluidObject and TestFluidObjectFactory that help in the testing of Distributed Data Structures (DDS). It can be used to create a Fluid object (TestFluidObject) with a given set of DDSes which can then be retrieved later as required.

For example, if you need a Fluid object with couple of SharedStrings, a SharedDirectory and a SparseMatrix, create a TestFluidObjectFactory as follows and use this factory to create the Fluid object:

new TestFluidObjectFactory([
    [ "sharedString1" /* id */, SharedString.getFactory() ],
    [ "sharedString2" /* id */, SharedString.getFactory() ],
    [ "directory" /* id */, SharedDirectory.getFactory() ],
    [ "matrix" /* id */, SparseMatrix.getFactory() ],
]);

The TestFluidObject will then create the above DDSes when initializing and they can then be retrieved by calling getSharedObject on it and providing the id that was used to create it:

const sharedString1 = testFluidObject.getSharedObject<SharedString>("sharedString1");
const sharedString1 = testFluidObject.getSharedObject<SharedString>("sharedString2");
const directory = testFluidObject.getSharedObject<SharedDirectory>("directory");
const matrix = testFluidObject.getSharedObject<SparseMatrix>("matrix");

If you want a DDS to be part of the registry so that it can be created later but don't want TestFluidObject to create it during initialization, use id as undefined in the TestFluidObjectFactory creation.

Op Processing Controller

OpProcessingController provides control over op processing in the tests. It lets you pause and resume the op processing in the containers / fluid objects. It also lets you wait until the ops have been processed by them and the server.

OpProcessingController should be created by passing in the ILocalDeltaConnectionServer that is used in the test. You can then register the Fluid objects / containers whose ops you want to control with it.

For example, consider the scenario where you perform some operations on a DDS and want to verify that the remote client's DDS have applied the operations. You have to wait until the op is sent to the server, the server processes the op, sends it to the remote client and the remote client processes the op.

You can use the OpProcessingController to wait for all that to happen by calling process on it. Check how SharedStringTest does that.

Usage

The typical usage for testing a Fluid object is as follows:

1. Create a LocalDeltaConnectionServer:

   const deltaConnectionServer: ILocalDeltaConnectionServer = LocalDeltaConnectionServer.create();

2. Create a LocalResolver:

   const urlResolver: IUrlResolver = new LocalResolver();

3. Create an IFluidCodeDetails and a TestFluidObjectFactory which will serve as the Fluid entry point (code details to factory mapping):

   const codeDetails: IFluidCodeDetails = {
       package: "sharedStringTestPackage",
       config: {},
   };
   const entryPoint = new TestFluidObjectFactory([["sharedString", SharedString.getFactory()]]);

   This can replaced by any IFluidDataStoreFactory or IRuntimeFactory. When the loader is asked to resolve a Container with the above code details, it will load the above factory.

4. Create a local Loader:

   const loader: ILoader = createLocalLoader([[codeDetails, entryPoint]], deltaConnectionServer, urlResolver);

5. Create and attach a Container by giving it a documentId which is used as a URL to resolve the container:

   const documentId = "testDocument";
   const container = await createAndAttachContainer(
           codeDetails, loader, urlResolver.createCreateNewRequest(documentId))

   We used the same IFluidCodeDetails that was used to create the Loader in step 3.

6. Get the Fluid object (TestFluidObject) by using requestFluidObject API in @fluidframework/runtime-utils. Then get the DDS to test:

   const fluidObject = await requestFluidObject<ITestFluidObject>(container, "default"); // "default" represent the default Fluid object.
   const sharedString = await fluidObject.getSharedObject<SharedString>("sharedString");

   The ITestFluidObject would have already created a SharedString based off the parameters we provided when creating the TestFluidObjectFactory in step 2.

7. To truly test collaboration, create a second Loader, Container, fluid object and DDS which will serve as a remote client:

   const documentUrl = `fluid-test://localhost/${documentId}`;
   const loader2: ILoader = createLocalLoader([[codeDetails, entryPoint]], deltaConnectionServer, urlResolver);
   const container2 = await loader2.resolver({ url: documentUrl });
   const fluidObject = await requestFluidObject<ITestFluidObject>(container2, "default");
   const sharedString2 = await fluidObject2.getSharedObject<SharedString>("sharedString");

   It is important to use the same ILocalDeltaConnectionServer to create the Loader and the same documentId to load the Container. This will make sure that we load the Container that was created earlier and do not create a new one.

These steps are demonstrated in the image below:

Note that the LocalDriver is created by the createLocalLoader method and does not need to explicitly created.

Example

The above usage is taken from SharedStringTest which is a very basic example of how to use these utils.

There are a number of other examples (some a little more complex) in the same directory.