Don’t use is() in Test::More

This results in:

The issue is fairly obvious when it’s laid out like this: is() does a string comparison, which means that trailing zero matters. One day, though, I promise you, you’ll hit a problem like this and will spend hours debugging it, only to smack your forehead when you finally see it. You can prevent that by explicitly giving a comparison operator to cmp_ok() instead.

This is somewhat similar to the issues seen in the ‘==’ operator in JavaScript and PHP, where the language makes a guess about how to coerce the types and gets it wrong (or at least, produces unexpected behavior). Those languages invented ‘===’ to solve that, which is madness.