7.3. Write Tests for Modules
In this chapter, you'll learn about moduleIntegrationTestRunner
from Medusa's Testing Framework and how to use it to write integration tests for a module's main service.
moduleIntegrationTestRunner Utility#
moduleIntegrationTestRunner
creates integration tests for a module's service. The integration tests run on a test Medusa application with only the specified module enabled.
For example, consider a Blog Module with a BlogModuleService
that has a getMessage
method:
To create an integration test for the module's service, create the file src/modules/blog/__tests__/service.spec.ts
with the following content:
1import { moduleIntegrationTestRunner } from "@medusajs/test-utils"2import { BLOG_MODULE } from ".."3import BlogModuleService from "../service"4import Post from "../models/post"5 6moduleIntegrationTestRunner<BlogModuleService>({7 moduleName: BLOG_MODULE,8 moduleModels: [Post],9 resolve: "./src/modules/blog",10 testSuite: ({ service }) => {11 describe("BlogModuleService", () => {12 it("says hello world", () => {13 const message = service.getMessage()14 15 expect(message).toEqual("Hello, World!")16 })17 })18 },19})20 21jest.setTimeout(60 * 1000)
The moduleIntegrationTestRunner
function accepts as a parameter an object with the following properties:
moduleName
: The registration name of the module.moduleModels
: An array of models in the module. Refer to this section if your module doesn't have data models.resolve
: The path to the module's directory.testSuite
: A function that defines Jest tests to run.
The testSuite
function accepts as a parameter an object having the service
property, which is an instance of the module's main service.
moduleIntegrationTestRunner
function is used as the type of the service
property.The tests in the testSuite
function are written using Jest.
Run Tests#
Run the following command to run your module integration tests:
test:integration:modules
script in package.json
, refer to the Medusa Testing Tools chapter.This runs your Medusa application and runs the tests available in any __tests__
directory under the src/modules
directory.
Pass Module Options#
If your module accepts options, you can set them using the moduleOptions
property of the moduleIntegrationTestRunner
's parameter.
For example:
moduleOptions
is an object of key-value pair options that your module's service receives in its constructor.
Write Tests for Modules without Data Models#
If your module doesn't have a data model, pass a dummy model in the moduleModels
property.
For example:
1import { moduleIntegrationTestRunner } from "@medusajs/test-utils"2import BlogModuleService from "../service"3import { model } from "@medusajs/framework/utils"4 5const DummyModel = model.define("dummy_model", {6 id: model.id().primaryKey(),7})8 9moduleIntegrationTestRunner<BlogModuleService>({10 moduleModels: [DummyModel],11 // ...12})13 14jest.setTimeout(60 * 1000)
Inject Dependencies in Module Tests#
Some modules have injected dependencies, such as the Event Module's service. When writing tests for those modules, you need to inject the dependencies that the module's service requires to avoid errors.
You can inject dependencies as mock dependencies that simulate the behavior of the original service. This way you avoid unexpected behavior or results, such as sending real events or making real API calls.
To inject dependencies, pass the injectedDependencies
property to the moduleIntegrationTestRunner
function.
For example:
1import { MockEventBusService, moduleIntegrationTestRunner } from "@medusajs/test-utils"2import { BLOG_MODULE } from ".."3import BlogModuleService from "../service"4import Post from "../models/post"5import { Modules } from "@medusajs/framework/utils"6 7moduleIntegrationTestRunner<BlogModuleService>({8 moduleName: BLOG_MODULE,9 moduleModels: [Post],10 resolve: "./src/modules/blog",11 injectedDependencies: {12 [Modules.EVENT_BUS]: new MockEventBusService()13 },14 testSuite: ({ service }) => {15 describe("BlogModuleService", () => {16 it("says hello world", async () => {17 const message = await service.getMessage()18 19 expect(message).toEqual("Hello, World!")20 })21 })22 },23})24 25jest.setTimeout(60 * 1000)
injectedDependencies
's value is an object whose keys are registration names of the dependencies you want to inject, and the values are the mock services.
In this example, you inject a mock Event Module service into the BlogModuleService
. Medusa exposes a MockEventBusService
class that you can use to mock the Event Module's service.
For other modules, you can create a mock service that implements the same interface as the original service. Make sure to use the same registration name as the original service when injecting it.
Other Options and Inputs#
Refer to the Test Tooling Reference for other available parameter options and inputs of the testSuite
function.
Database Used in Tests#
The moduleIntegrationTestRunner
function creates a database with a random name before running the tests. Then, it drops that database after all the tests end.
To manage that database, such as changing its name or perform operations on it in your tests, refer to the Test Tooling Reference.