Examples from Working Effectively With Unit Tests by Jay Fields
Tests as first presented in the book is in the wewut.original package, final state in the wewut.refactored package.
Note: I took the liberty of changing linebreaks throughout, as the examples in the book were heavily compressed to
fit on narrow lines. Aside from that and replacing a tab with a space in wewut.original.CustomerTest::rentalInfo()
that caused tests to fail, the tests are exactly as presented in the book.