In a language where most errors will be runtime errors (Ruby), the inheritace problem described in the article is much less of a problem. In such a language (e

In a language where most errors will be runtime errors (Ruby), the inheritace problem described in the article is much less of a problem. In such a language (e.g. Ruby), you will need test suites where languages with (strong) types use the type system to prove some level of correctness. I used to be a fan of dyn typed langs (Ruby), but I've changed, I prefer strongly typed langs now for anything more than quick throw away scripts.