Rewrite of example from https://dzone.com/articles/stop-mocking-start-newing

ExplanationOfOrderShipping.java

// The first thing I did was generalize the "orders have free shipping to Australia" concept
// to "orders adjust their shipping charges in some way".
// I wouldn't want Order to get cluttered with lots of shipping rules.
// Instead of doing this in constructor, it could instead have a method like
// order.adjustShipping(shippingAdjustments).
@Test
public void whenCreatingAnOrder_AdjustsShippingCharges() {
	ShippingAdjustments mockedShippingAdjustments = mock(ShippingAdjustments.class);
	Country mockedCountry = mock(Country.class);
	Order order = new Order(mockedCountry, mockedShippingAdjustments, other, parameters);
	
	verify(mockedShippingAdjustments).adjustForCountry(order, mockedCountry);
}

public class Order {

	private Country country;
	
	public Order(Country country, ShippingAdjustments shippingAdjustments, Other other, Parameters parameters) {
		this.country = country;
		shippingAdjustments.adjustForCountry(this, this.country);
	}
}

// I then tested the ShippingAdjustments concept as follows...
@Test
public void whenEvaluatingShippingAdjustments_AppliesAllAdjustments() {
	ShippingAdjustment mockAdjustment1 = mock(ShippingAdjustment.class);
	ShippingAdjustment mockAdjustment2 = mock(ShippingAdjustment.class);
	ShippingAdjustment mockAdjustment3 = mock(ShippingAdjustment.class);
	Shippable mockShippable = mock(Shippable.class);
	Country mockCountry = mock(Country.class);
	ShippingAdjustments shippingAdjustments = new ShippingAdjustments(mockAdjustment1, mockAdjustment2, mockAdjustment3);
	
	shippingAdjustments.adjustForCountry(shippable, mockCountry);
	
	verify(mockAdjustment1).adjustForCountry(mockShippable, mockCountry);
	verify(mockAdjustment2).adjustForCountry(mockShippable, mockCountry);
	verify(mockAdjustment3).adjustForCountry(mockShippable, mockCountry);
}

// This eludes to the Shippable and ShippingAdjustment interface
public interface Shippable {
	
}

public interface ShippingAdjustment {
	
	void adjustForCountry(Shippable shippable, Country country);
}

public class ShippingAdjustments {

	private List<ShippingAdjustment> shippingAdjustments;

	public ShippingAdjustments(ShippingAdjustment ... shippingAdjustments) {
		this.shippingAdjustments = Arrays.asList(shippingAdjustments);
	}
	
	public void adjustForCountry(Shippable shippable, Country country) {
		for(ShippingAdjustment adjustment : shippingAdjustments) {
			adjustment.adjustForCountry(shippable, country);
		}
	}
}

// Then testing the shipping adjustment in question, we can also flesh out
// the behavior for Shippable

@Test
public void free_shipping_applies_within_australia() {
	Shippable mockShippable = mock(Shippable.class);
	
	FreeShippingAdjustment freeShippingAdjustment = new FreeShippingAdjustment();
	
	freeShippingAdjustment.adjustForCountry(mockShippable, new Country("Australia"));
	
	verify(mockShippable).freeShipping();
}

// Would also have a test that verifies it does not apply the adjustment when the country does not match

// This gives a new method for Shippable
public interface Shippable {
	
	void freeShipping();
}

// We can make Order implement Shippable and update the implementation
// along with a test for it
public class Order implements Shippable {

	private Country country;
	private boolean freeShipping;
	
	public Order(Country country, ShippingAdjustments shippingAdjustments, Other other, Parameters parameters) {
		this.country = country;
		this.freeShipping = false;
		shippingAdjustments.adjust(this);
	}
	
	public void freeShipping() {
		this.freeShipping = true;
	}
}

public class FreeShippingAdjustment implements ShippingAdjustment {

	private Country appliesForCountry;
	
	public FreeShippingAdjustment() {
		this.appliesForCountry = new Country("Australia");
	}
	
	public void adjustForCountry(Shippable shippable, Country country) {
		if(appliesForCountry.equals(country)) {
			shippable.freeShipping();
		}
	}
}

FreeShippingAdjustment.java

public class FreeShippingAdjustment implements ShippingAdjustment {

	private Country appliesForCountry;
	
	public FreeShippingAdjustment() {
		this.appliesForCountry = new Country("Australia");
	}
	
	public void adjustForCountry(Shippable shippable, Country country) {
		if(appliesForCountry.equals(country)) {
			shippable.freeShipping();
		}
	}
}

// Tests
@Test
public void free_shipping_applies_within_australia() {
	Shippable mockShippable = mock(Shippable.class);
	
	FreeShippingAdjustment freeShippingAdjustment = new FreeShippingAdjustment();
	
	freeShippingAdjustment.adjustForCountry(mockShippable, new Country("Australia"));
	
	verify(mockShippable).freeShipping();
}

Order.java

public class Order implements Shippable {

	private Country country;
	private boolean freeShipping;
	
	public Order(Country country, ShippingAdjustments shippingAdjustments, Other other, Parameters parameters) {
		this.country = country;
		this.freeShipping = false;
		shippingAdjustments.adjustForCountry(this, this.country);
	}
	
	public void freeShipping() {
		this.freeShipping = true;
	}
}

// Tests
@Test
public void whenCreatingAnOrder_AdjustsShippingCharges() {
	ShippingAdjustments mockedShippingAdjustments = mock(ShippingAdjustments.class);
	Country mockedCountry = mock(Country.class);
	Order order = new Order(mockedCountry, mockedShippingAdjustments, other, parameters);
	
	verify(mockedShippingAdjustments).adjustForCountry(order, mockedCountry);
}

ShippingAdjustment.java

public interface ShippingAdjustment {
	
	void adjustForCountry(Shippable shippable, Country country);
}

ShippingAdjustments.java

public class ShippingAdjustments {

	private List<ShippingAdjustment> shippingAdjustments;

	public ShippingAdjustments(ShippingAdjustment ... shippingAdjustments) {
		this.shippingAdjustments = Arrays.asList(shippingAdjustments);
	}
	
	public void adjustForCountry(Shippable shippable, Country country) {
		for(ShippingAdjustment adjustment : shippingAdjustments) {
			adjustment.adjustForCountry(shippable, country);
		}
	}
}

// Tests
@Test
public void whenEvaluatingShippingAdjustments_AppliesAllAdjustments() {
	ShippingAdjustment mockAdjustment1 = mock(ShippingAdjustment.class);
	ShippingAdjustment mockAdjustment2 = mock(ShippingAdjustment.class);
	ShippingAdjustment mockAdjustment3 = mock(ShippingAdjustment.class);
	Shippable mockShippable = mock(Shippable.class);
	Country mockCountry = mock(Country.class);
	ShippingAdjustments shippingAdjustments = new ShippingAdjustments(mockAdjustment1, mockAdjustment2, mockAdjustment3);
	
	shippingAdjustments.adjustForCountry(shippable);
	
	verify(mockAdjustment1).adjustForCountry(mockShippable, mockCountry);
	verify(mockAdjustment2).adjustForCountry(mockShippable, mockCountry);
	verify(mockAdjustment3).adjustForCountry(mockShippable, mockCountry);
}