In Class Test

Given the 4 @Test methods shown, how many times does the @Before method execute?
Just one, it initializes global variables. In this case, we are creating objects from the class we want to test.
The contract for equals() states that no exceptions may be thrown. Instead, equals() is supposed to return false if passed a null argument.
Write a JUnit test that verifies this property for the EH class.
```
@Test public void noNPE() {
       assertEquals(false, eh1.equals(null));
}
```
Using the given EH objects, write a test that verifies that equals() returns false if the objects are, in fact, not equal.
```
@Test public void equalsFalse() {
       assertEquals(false, eh1.equals(eh2));
}
```
Using the given EH objects, write a test that verifies that equals() returns true if the objects are, in fact, equal.
```
@Test public void equalsTrue() {
       assertEquals(true, eh1.equals(eh3));
}
```
Using the given EH objects, write a test to verify that hashCode() is consistent with equals. This test should fail if hashCode() is commented out (as shown), but pass if hashCode() is implemented.
```
@Test public void hashConsistent() {
       assertEquals(true, eh1.hashCode() == eh3.hashCode());
}
```

Testing and learning