package beginner;

import static com.sandwich.koan.constant.KoanConstants.__;

import static com.sandwich.util.Assert.assertEquals;

import java.text.MessageFormat;

import java.util.ArrayList;

import java.util.List;

import com.sandwich.koan.Koan;

public class AboutObjects {

@Koan

public void newObjectInstancesCanBeCreatedDirectly() {

assertEquals(new Object() instanceof Object, __);

}

@Koan

public void allClassesInheritFromObject() {

class Foo {}

Class<?>[] ancestors = getAncestors(new Foo());

assertEquals(ancestors[0], __);

assertEquals(ancestors[1], __);

}

@Koan

public void objectToString() {

Object object = new Object();

// TODO: Why is it best practice to ALWAYS override toString?

String expectedToString = MessageFormat.format("{0}@{1}", Object.class.getName(), Integer.toHexString(object.hashCode()));

assertEquals(expectedToString, __); // hint: object.toString()

}

@Koan

public void toStringConcatenates() {

final String string = "ha";

Object object = new Object() {

@Override public String toString() {

return string;

}

};

assertEquals(string + object, __);

}

@Koan

public void toStringIsTestedForNullWhenInvokedImplicitly() {

String string = "string";

assertEquals(string + null, __);

}

private Class<?>[] getAncestors(Object object) {

List<Class<?>> ancestors = new ArrayList<Class<?>>();

Class<?> clazz = object.getClass();

while(clazz != null) {

ancestors.add(clazz);

clazz = clazz.getSuperclass();

}

return ancestors.toArray(new Class[]{});

}

}