10 is undef, undef, 'undef is undef';
11 isnt 0, undef, 'zero is not undef';
12 isnt undef, 0, 'undef is not zero';
13 is 0, 0, 'zero is zero';
14 is 1, 1, 'one is one';
15 isnt '1.0', 1, '1.0 is not one string-wise';
17 my @fruits = ('pear', 'apple');
18 my @veggies = ('lettuce', 'spinach');
19 is @fruits, @veggies, 'is() forces scalar context';
20 my @more_fruits = (@fruits, 'banana');
21 isnt @fruits, @more_fruits, 'isnt() forces scalar context';