ScannerTest.java

public class ScannerTest {
  @Test
  public void shouldDisplayThePriceUsingTaxes() {
    Display display = mock(Display.class);
    Calculator calculator = mock(Calculator.class);
    Repository repository = mock(Repository.class);
    when(calculator.calculate("$100")).thenReturn("$119");
    when(repository.getProductPrice("ABC123")).thenReturn("$100");
    Scanner scanner = new Scanner(repository, calculator, display);
    
    scanner.scan("ABC123");

    verify(display).print("$119");
  }

  @Test
  public void shouldUseTheRepositoryWhenScanning() {
    Display display = mock(Display.class);
    Calculator calculator = mock(Calculator.class);
    Repository repository = mock(Repository.class);
    when(calculator.calculate("$100")).thenReturn("$119");
    Scanner scanner = new Scanner(repository, calculator, display);
    
    scanner.scan("ABC123");

    verify(repository).getProductPrice("ABC123");
  }

}