@Test public void should_not_interact_with_web_service_in_any_way_if_person_is_null() { systemUnderTest.transferTaxFor(null); verifyZeroInteractions(taxService); }
public void transferTaxFor(Person person) { if (person == null) { return; } taxService.transferTaxFor(person); }
TaxTransferer { public void transferTaxFor(Person person) { if (person == null) { return; } taxService.transferTaxFor(person); } }
TaxTransferer { public void transferTaxFor(Person person) { if (person == null) { return; } taxService.transferTaxFor(person); } TaxTransferer(TaxService taxService); }
TaxTransferer { public void transferTaxFor(Person person) { if (person == null) { return; } taxService.transferTaxFor(person); } TaxTransferer(TaxService taxService); void transferTaxFor(Person person); }
TaxTransferer { public void transferTaxFor(Person person) { if (person == null) { return; } taxService.transferTaxFor(person); } TaxTransferer(TaxService taxService); void transferTaxFor(Person person);  }