UNC COMP 410 - Assn 5

BinaryHeapTest.java

import static org.junit.Assert.*;
import org.junit.Test;

public class BinaryHeapTest {
	/**
	 * If you are expecting null, then don't use this function - it is not null 
	 * safe.
	 */
	private void entryPairAssertEqual(EntryPair expect, EntryPair actual) {
		if (expect.getPriority() != actual.getPriority() || 
				!expect.getValue().equals(actual.getValue())) {
			String message = String.format("Expected %s, got %s", expect, actual);
			fail(message);
		}
	}
	
	@Test
	public void testGetMinEmpty() {
		HeapInterface heap = new MinBinHeap();
		assertEquals(null, heap.getMin());
	}
	
	@Test
	public void delMinEmpty() {
		HeapInterface heap = new MinBinHeap();
		heap.delMin();
		
		assertEquals(null, heap.getMin());
		assertEquals(0, heap.size());
	}
	
	@Test
	public void testSizeEmpty() {
		HeapInterface heap = new MinBinHeap();
		assertEquals(0, heap.size());
	}
	
	/**
	 * Insert the pairs in random order, to ensure that the heap is
	 * maintaining the heap order property
	 * 
	 * Putting this as a static member of the class makes it easier to test with 
	 * differently sized inputs to the heap, without having to change the size 
	 * constants found in a few of the tests
	 * 
	 * Just make sure that the minimum two elements are ("1", 1) and ("2", 2)
	 * (or otherwise change the test cases) and everything should work
	 */
	private static EntryPair[] CONSTRUCTION_PAIRS = new EntryPair[] {
				new EntryPair("6", 6),
				new EntryPair("3", 3),
				new EntryPair("5", 5),
				new EntryPair("1", 1),
				new EntryPair("4", 4),
				new EntryPair("2", 2),
				new EntryPair("7", 7),
				new EntryPair("5", 5),
				new EntryPair("3", 3),
		};
	
	private HeapInterface makeNonEmptyHeapInsert() {
		HeapInterface heap = new MinBinHeap();
		for (EntryPair pair: CONSTRUCTION_PAIRS) {
			heap.insert(pair);
		}
		
		return heap;
	}
	
	private HeapInterface makeNonEmptyHeapBuild() {
		HeapInterface heap = new MinBinHeap();
		heap.build(CONSTRUCTION_PAIRS);
		
		return heap;
	}
	
	private void testGetMinNonEmpty(HeapInterface heap) {
		EntryPair min_pair = new EntryPair("1", 1);
		entryPairAssertEqual(min_pair, heap.getMin());
	}
	
	@Test
	public void testGetMinBuild() {
		testGetMinNonEmpty(makeNonEmptyHeapBuild());
	}
	
	@Test
	public void testGetMinInsert() {
		testGetMinNonEmpty(makeNonEmptyHeapInsert());
	}
	
	private void testDelMinNonEmpty(HeapInterface heap) {
		heap.delMin();
		
		EntryPair min_pair = new EntryPair("2", 2);
		entryPairAssertEqual(min_pair, heap.getMin());
		assertEquals(CONSTRUCTION_PAIRS.length - 1, heap.size());
	}
	
	@Test
	public void testDelMinBuild() {
		testDelMinNonEmpty(makeNonEmptyHeapBuild());
	}
	
	@Test
	public void testDelMinInsert() {
		testDelMinNonEmpty(makeNonEmptyHeapInsert());
	}
	
	public void testSizeNonEmpty(HeapInterface heap) {
		assertEquals(CONSTRUCTION_PAIRS.length, heap.size());
	}
	
	@Test
	public void testSizeBuild() {
		testSizeNonEmpty(makeNonEmptyHeapBuild());
	}
	
	@Test 
	public void testSizeInsert() {
		testSizeNonEmpty(makeNonEmptyHeapInsert());
	}
}