Tilstand og oppførsel - UpOrDownCounter-oppgave (JExercise)

import jexutil.JExercise;
import junit.framework.TestCase;

@JExercise(
        tests="", // We don't want to test this element as a whole, since we can test the parts.
        description="A class that counts from a start value up or down to an end value. " +
                "The counting is constrained by the values provided to constructor and performed by the count() method."
)
public class UpOrDownCounterTest extends TestCase {
    @Override
    protected void setUp() throws Exception {
        super.setUp();
    }
    
    private void testCount(UpOrDownCounter counter, int end, int delta) {
        boolean result = true;
        while (delta > 0 ? counter.getCounter() < end : counter.getCounter() > end) {
            assertTrue("Before reaching the end value, the count() method should return false. ", result);
            int i = counter.getCounter();
            result = counter.count();
            int expected = i + delta;
            assertEquals("When counting from " + i + " the result should be " + expected + ". ", expected, counter.getCounter());
        }
        assertFalse("When reaching the end value, the count method should return true. ", result);
        assertEquals("After reaching the end value, the counter should not change. ", end, counter.getCounter());
        assertFalse("After reaching the end value, the count() method should return true. ", counter.count());
        assertEquals("After reaching the end value, the counter should not change. ", end, counter.getCounter());
    }
    
    @JExercise(
            tests="UpOrDownCounter(int,int)",
            description="A constructor that initializes the UpOrDownCounter class with the provided start and end value. " +
                    "After initialization the counter should be the start value. "
    )
    public void testUpOrDownCounter() {
        UpOrDownCounter counter13 = new UpOrDownCounter(1, 3);
        assertEquals("After instantiating an UpOrDownCounter the counter should be the start value. ", 1, counter13.getCounter());
        UpOrDownCounter counter31 = new UpOrDownCounter(3, 1);
        assertEquals("After instantiating an UpOrDownCounter the counter should be the start value. ", 3, counter31.getCounter());
    }
    @JExercise(
            tests="UpOrDownCounter(int,int)",
            description="A constructor that initializes the UpOrDownCounter class with the provided start and end value. " +
                    "If the start and end values are equal, an IllegalArgumentException should be thrown. "
            )
    public void testUpOrDownCounterWithException() {
        Exception iae = null;
        try {
            new UpOrDownCounter(0, 0);
            fail("When the start and end values are equal an IllegalArgumentException should be thrown. ");
        } catch (Exception e) {
            iae = e;
        }
        assertTrue("When the start and end values are equal an IllegalArgumentException should be thrown, ", iae instanceof IllegalArgumentException);
    }
    
    @JExercise(
            tests="boolean count()",
            description="A method that steps the counter, unless it has reached the end value. " +
                    "The method returns true as long as the counter has not reached the end value, and false otherwise. " +
                    "This test checks that it properly steps upwards, when the end value is larger than the start value."
    )
    public void testCountUp() {
        UpOrDownCounter counter13 = new UpOrDownCounter(1, 3);
        testCount(counter13, 3, 1);
    }
    @JExercise(
            tests="boolean count()",
            description="A method that steps the counter, unless it has reached the end value. " +
                    "The method returns true as long as the counter has not reached the end value, and false otherwise. " +
                    "This test checks that it properly steps downwards, when the end value is smaller than the start value."
            )
    public void testCountDown() {
        UpOrDownCounter counter31 = new UpOrDownCounter(3, 1);
        testCount(counter31, 1, -1);
    }
}