anchor.diff:  	    assertEquals(result, [1, 2, 3, 30, 40, 1], 'takes the union of a list of nested arrays');
   	}
   	
  -	public void function testArraysDifference() {
  +	public void function testDifference() {
   	    var result = _.difference([1, 2, 3], [2, 30, 40]);
   	    assertEquals(result, [1, 3], 'takes the difference of two arrays');
   
  
positive.code: 		assertEquals(arrayLen(result), 4, "The resulting array should not be sparse");
  	}
  	
  	public void function testArraysIntersection() {
  	    var stooges = ['moe', 'curly', 'larry'];
  	    var leaders = ['moe', 'groucho'];
  	    assertEquals(_.intersection(stooges, leaders), ['moe'], 'can take the set intersection of two arrays');
  
negative.code: 	    // equal(result.join(''), 'moe', 'works on an arguments object');
  	}
  	
  	public void function testUnion() {
  	    var result = _.union([1, 2, 3], [2, 30, 1], [1, 40]);
  	    assertEquals(result, [1, 2, 3, 30, 40], 'takes the union of a list of arrays');
  
  