Mocks focus on the internal

mocksarebad.js

it("When a valid product is about to be deleted, ensure data access DAL was called once, with the right product and right config", async () => {
    //Assume we already added a product
    const dataAccessMock = sinon.mock(DAL);
    //hmmm BAD: testing the internals is actually our main goal here, not just a side-effecr
    dataAccessMock.expects("deleteProduct").once().withArgs(DBConfig, theProductWeJustAdded, true, false);
    new ProductService().deletePrice(theProductWeJustAdded);
    mock.verify();
  });