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