Bad test helpers

BadTestHelpers.java

Invoice invoice;

@BeforeEach
void setup() {
  createInvoiceToSave();
}

@Test
void standardInvoice() {
  mockCustomerFinder();
  
  createInvoiceUseCase.create(12345, new BigDecimal(100));
  
  assertInvoiceSaved();
}

void mockCustomerFinder() {
  when(authenticatedCustomerFinder.apply()).thenReturn(new Customer("Marcin", "Gryszko"));
}

void createInvoiceToSave() {
  var customer = new Customer("Marcin", "Gryszko");
  invoice = new Invoice(12345, new BigDecimal(100), customer);
}

void assertInvoiceSaved() {
  verify(invoiceRepository.save(invoice));
}