Let's say I have a transactional update of my database
...
const sendMoney = prisma.account.update({ where: { id: 1 }, data: { ... } })
const receiveMoney = prisma.account.update({ where: { id: 2 }, data: { ... } })
const [accountOfSender, accountOfReceiver] = await prisma.$transaction([
sendMoney,
receiveMoney
])
...
And I have a unit test which verifies this transaction
describe('The money transfer use case', () => {
let mockedContext: MockContext
let moneyTransferUseCase: MoneyTransferUseCase
beforeEach(() => {
mockedContext = createMockedContext()
moneyTransferUseCase = new MoneyTransferUseCase(mockedContext.prisma)
})
it('should transfer money between two accounts', () => {
...
const updatedAccount = { ... }
mockedContext.prisma.account.update.mockReturnedValue(Promise.resolve(updatedAccount))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - throws an error
...
})
Error message
TS2345: Argument of type 'Promise<Account>' is not assignable to parameter of type 'Prisma__AccountClinet<Account>'.
Type 'Promise<Account>' is missing the following properties from type 'Prisma__AccountClient<Account>': _dmmf, _fetcher, _queryType, _rootField, and 11 more.
63 mockedContext.prisma.account.update.mockReturnValue(Promise.resolve(updatedAccount))
the most important from this error message is this
Type 'Promise<Account>' is missing the following properties from type 'Prisma__AccountClient<Account>': _dmmf, _fetcher, _queryType, _rootField, and 11 more.
I can understand that Promise.resolve(updatedAccount) is not enough to mock the prisma promise. But how to mock it? Documentation says nothing about this. Any ideas?
Update
I thought about it for a bit and decided that I can mock prisma.$transaction([ ... ]) call itself
...
const expectedAccount1 = { ... }
const expectedAccount2 = { ... }
mockedContext.prisma.$transaction.mockResolvedValue([
expectedAccount1,
expectedAccount2
])
...
It exactly returns what I need but intermediate calls
...
const sendMoney = prisma.account.update({ where: { id: 1 }, data: { ... } }) // undefined
const receiveMoney = prisma.account.update({ where: { id: 2 }, data: { ... } }) // undefined
...
returns undefined during the test. I don't useŠµ these results anywhere other than passing it to the prisma.$transaction function.
So it seems that test works as expected, but not sure if it is a good approach.