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

public class TestBinarySearchTree {
	
	private BinarySearchTree empty() {
		return new BinarySearchTree() ;		
	}
	
	private BinarySearchTree singleton() {
		BinarySearchTree t = new BinarySearchTree() ;	
		t.insert(0);
		return t ;
	}

	private BinarySearchTree t1() {
		BinarySearchTree t = new BinarySearchTree() ;	
		t.insert(0);
		t.insert(-10);
        t.insert(10);
		return t ;
	}

	@Test
	public void find() {
		assertTrue(singleton().find(0).equals(0)) ;
		assertTrue(t1().find(10).equals(10)) ;
		assertTrue(t1().find(-10).equals(-10)) ;
	}
	
	@Test
	public void findBO() {
		assertNull(empty().find(0)) ;
		assertNull(singleton().find(10)) ;
		assertNull(t1().find(99)) ;
	}
	
	@Test
	public void findMax() {
		// surpressed negative-result test: assertNull(empty().findMax()) ;
		assertTrue(singleton().findMax().equals(0)) ;
		assertTrue(t1().findMax().equals(10)) ;
	}
	
	@Test
	public void findMin() {
		assertTrue(singleton().findMin().equals(0)) ;
		assertTrue(t1().findMin() .equals(-10)) ;
	}
	
	@Test
	public void findMinBO() {
		assertNull(empty().findMin()) ;
	}
	
	@Test 
	public void isEmpty() {
		assertTrue(empty().isEmpty()) ;
	}
	
	@Test 
	public void isEmptyBO() {
		assertFalse(singleton().isEmpty()) ;
		assertFalse(t1().isEmpty()) ;
	}
	
	@Test
	public void makeEmpty() {
		BinarySearchTree t = empty() ; t.makeEmpty() ;
		assertTrue(t.isEmpty()) ;
		t = singleton() ; t.makeEmpty() ;
		assertTrue(t.isEmpty()) ;
		t = t1() ; t.makeEmpty() ;
		assertTrue(t.isEmpty()) ;
	}
	
	@Test
	public void insert() {
		BinarySearchTree t ;
		t = empty(); t.insert(0) ;
		assertTrue(t.findMax().equals(0)) ;
		
		t = singleton() ; t.insert(0) ; t.remove(0) ;
		assertTrue(t.isEmpty());
		
		t = singleton() ; t.insert(10) ;
		assertTrue(t.findMax().equals(10)) ;

		t = t1() ; t.insert(-5) ;
		assertTrue(t.findMin().equals(-10)) ;
		assertTrue(t.findMax().equals(10)) ;
		assertTrue(t.find(-5).equals(-5)) ;
		
		t = t1() ; t.insert(-15) ;
		assertTrue(t.findMin().equals(-15)) ;
		assertTrue(t.findMax().equals(10)) ;

		t = t1() ; t.insert(15) ;
		assertTrue(t.findMin().equals(-10)) ;
		assertTrue(t.findMax().equals(15)) ;
	}
	
	@Test
	public void insertBO() {
		BinarySearchTree t ;
		// test on inserts that suposed have no effect:
		t = t1() ; t.insert(10) ;
		assertTrue(t.findMax().equals(10)) ;
		t = t1() ; t.insert(-10) ;
		assertTrue(t.findMin().equals(-10)) ;
	}
	
	@Test
	public void remove() {
		BinarySearchTree t ;

		t = t1() ; t.remove(10) ;
		assertNull(t.find(10)) ;
		
		t = t1() ; t.remove(-10) ;
		assertNull(t.find(-10)) ;


	}
	
	@Test
	public void removeBO() {
		BinarySearchTree t ;
		// testing non-effectfull remove:
		
		t = empty() ; t.remove(0) ;
		assertTrue(t.isEmpty()) ;
		
		t = singleton() ; t.remove(0) ;
		assertTrue(t.isEmpty()) ;
		
		t = singleton() ; t.remove(10) ;
		assertFalse(t.isEmpty()) ;
		
		t = t1() ; t.remove(-5) ;
		assertNull(t.find(-5)) ;
	}
	
}