Object-Oriented Techniques - Java - page 296

method contract pretty much makes it impossible to compare a subclass with a superclass
correctly, so we now use class equality (see Chapter 23, Reflection, or “A Class Named
Class” for details on the class descriptor).

Here is a basic JUnit test (see Avoiding the Need for Debuggers with Unit Testing ) for the
EqualsDemo class:

/** Some JUnit test cases for EqualsDemo.
* Writing a full set is left as "an exercise for the reader".
*/
public public class class EqualsDemoTest EqualsDemoTest {

/** an object being tested */
EqualsDemo d1 ;
/** another object being tested */
EqualsDemo d2 ;

/** Method to be invoked before each test method */
@Before
public public void void setUp () {

d1 = new new EqualsDemo ();

d2 = new

new EqualsDemo ();

}

@Test
public

public void void testSymmetry () {

assertTrue ( d1 . equals ( d1 ));

}

@Test
public

public void void testSymmetric () {

assertTrue ( d1 . equals ( d2 ) && d2 . equals ( d1 ));

}

@Test
public

public void void testCaution () {

assertTrue (! d1 . equals ( null

null ));

}

}

With all that testing, what could go wrong? Well, some things still need care. What if the ob-
ject is a subclass of EqualsDemo ? We should test that it returns false in this case.