Unit Testing shows flawed test example

[DanielMenke]

this test:

test('should fail if user does not accept terms', async () => {
  const user = {
    id: 1,
    name: 'Rich Haines',
    email: 'hello@prisma.io',
    acceptTermsAndConditions: false,
  }

  prismaMock.user.create.mockRejectedValue(new Error('User must accept terms!'))

  await expect(createUser(user)).resolves.toEqual(
    new Error('User must accept terms!')
  )
})

tests this function:

export async function createUser(user: CreateUser, ctx: Context) {
  if (user.acceptTermsAndConditions) {
    return await ctx.prisma.user.create({
      data: user,
    }) // ALWAY THROWS, DUE TO THE MOCK
  } else {
    return new Error('User must accept terms!')
  }
}

This line
prismaMock.user.create.mockRejectedValue(new Error('User must accept terms!'))

lets the test succeed no matter which path the execution goes. If the code gets changed in some way that ctx.prisma.user.create actually gets executed, the test would suggest that the guard is still intact although it isn't.

[sabinadams]

After testing this myself, it appears the test behaves correctly as is. I did decide to change the user.create mock to simply do nothing as it doesn't matter in this scenario how the query behaves.