How your 'Mother' can help you 'Build' cleaner unit tests - Part II

public class Address {
  private final String lineOne;
  private final String lineTwo;
  private final String city;
  private final String state;

  private Address() {
    // Prevent other objects from calling the constructor
  }

  // ... other methods omitted for brevity

  public static final class Builder {
    private String lineOne;
    private String lineTwo;
    private String city;
    private String state;

    public Builder lineOne(String lineOne) {
      this.lineOne = lineOne;
      return this;
    }

    public Builder lineTwo(String lineTwo) {
      this.lineTwo = lineTwo;
      return this;
    }

    // ... city() and state() builder methods omitted for brevity

    public Address build() {
      return new Address(this);
    }
  }

  private Address(Builder builder) {
    this.lineOne = builder.lineOne;
    this.lineTwo = builder.lineTwo;
    this.city = builder.city;
    this.state = builder.state;
  }
}


public class ShippingServiceTest {
  private Address.Builder shippingAddressBuilder;

  @Before
  public void setUp() {
    shippingAddressBuilder = new Address.Builder()
      .lineOne("123 Main St.")
      .lineTwo("")
      .city("Chicago")
      .state("IL");
  }

  @Test
  public void shipsToTheAddress() {
    ShippingService service = new ShippingService();
    Address shippingAddress = shippingAddressBuilder.build();

    Shipment shipment = service.shipTo(shippingAddress);

    assertTrue(shipment.wasSuccessful());
    assertEquals(shipment.getDeliveryAddress(), shippingAddress);
  }

  @Test
  public void cannotShipToHawaii() {
    ShippingService service = new ShippingService();
    Address shippingAddress = shippingAddressBuilder.state("HI").build();

    Shipment shipment = service.shipTo(shippingAddress);

    assertFalse(shipment.wasSuccessful());
    assertEquals(shipment.getFailureReason(), "Cannot ship to Hawaii.");
  }
}