Each piece is delimited by punctuation

What are considered punctuation in this kata?

• random tests are not random enough (the content of the strings is way too much regular. Both about the letters and the punctuation signs)
• missing edge case: "g12, Gmqggozierg11" -> "g12" (to be sure that single g/G are ignored.

Suggestion part:

• would be good to test for more punctuation signs.