15 - Test::More

Test-first design
ok($this eq $that, 'Is this equal to that?');
#      ok 1 - Is this equal to that? 

my $foo = 'abc';  my $bar = 'def';
is( $foo, $bar,   'Is foo the same as bar?' );
# not ok 2 - Is foo the same as bar?
#     Failed test (foo.t at line 139)
#          got: 'abc'
#     expected: 'def'

like( $this, qr/that/, $test_name );

ok( grep(/foo/, @users), "There's a foo user" ) or
    diag("Since there's no foo, check that /etc/bar is set up right");
# not ok 3 - There's a foo user
#     Failed test (foo.t at line 52)
# Since there's no foo, check that /etc/bar is set up right.