public void testEqualSubsetIntersection() throws Exception {

		for (int i = 0; i < 100; i++) {

			int len = (int)(Math.random() * (10 - 1) + 1);
			RBtree a = randomRB( len );	
			RBtree b = a; 
			if (!a.equal( b ) ) {
				throw new Exception("FAILURE THE TWO SETS ARE NOT EQUAL");
			}

			if (!a.subset( a.intersection( b )) && !b.subset( b.intersection( a ))) {
				throw new Exception("FAILURE THE TWO SETS ARE NOT SUBSETS OF THE INTERSECTION");
			}

			equalSubsetIntersectionTest++;
		}
	}