TestHelpersInlined.java

int id = 12345;
BigDecimal amount = new BigDecimal(100);
Customer customer = new Customer(null, null);

@Test
void standardInvoice() {
  when(authenticatedCustomerFinder.apply()).thenReturn(customer);
  
  createInvoiceUseCase.create(id, amount);
  
  verify(invoiceRepository.save(new Invoice(id, amount, customer)));
}