CODEWITHSUNDEEP
javascriptjestjstypeorm
Rafael Silva
Rafael Silva

Reputation: 149

How mock a test for EntityManager.transaction() in TypeOrm?

I have this function in my controller:

async save(req: Request, res: Response) {
    try {            
        const user = new User();
        user.nome = 'Jhon Doe';
        
        const admin = new Morador;
        admin.user = user;
        
        await getManager().transaction( async entity => {
            await entity.save(user);
            await entity.save(admin);
        });

        res.status(201).json(admin);

    } catch (e) {
        res.sendStatus(500);
    }
}

I need to mock this function:

await getManager().transaction( async entity => {
    await entity.save(user);
    await entity.save(admin);
});

I need to receive the input values from the entity.save function. How to do this with Jest?

Upvotes: 0

Views: 2332

Answers (1)

Rafael Silva
Rafael Silva

Reputation: 149

After studying further how the getManager().transaction() function works, I was able to implement the mock like this:

function mockGetManager(objects: Array<any>) {

    async function mockEntityManager() {

        const entityManager = {} as EntityManager;
  
        entityManager.save = function save(entity: any): Promise<any> {
            // todo
            return Promise.resolve(true);
        }

        entityManager.update = function update(entity: any, update: any): Promise<any> {
            // todo
            return Promise.resolve(true);
        }

        entityManager.findOne = function findOne(query: any): Promise<any> {
            // todo
            return Promise.resolve(true);
        }

        entityManager.find = function find(query?: any): Promise<Array<any>> {
            // todo
            return Promise.resolve([]);
        }

        entityManager.delete = function del(query: any): Promise<any> {
            // todo
            return Promise.resolve(true);
        }
        
        await arguments[0](entityManager);
    }

    getManager().transaction = jest.fn().mockImplementation(mockEntityManager);
}

The function can be called this way when using:

const saved = [];
mockGetManager(saved);
expect(saved).toHaveLength(numberObjectsSaved);

I thought the solution was good because in this case I needed to test only the logic of the controller, so there is no need to test the transaction, as it is tested in the unit tests of the models.

I hope I can have helped someone.

Upvotes: 1

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