On Mac when word-selecting backwards starting with the caret on the middle of a word and then word-selecting forward, the caret is left in the same place where it was, instead of directly selecting to the end of the word (which is windows/unix behavior).

mac:
Extend backward and then forward by word: PASS
Extend forward and then backward by word: PASS
Extend backward and then forward by line: PASS
Extend forward and then backward by line: PASS
Extend backward and then forward by paragraph: PASS
Extend forward and then backward by paragraph: PASS
win:
Extend backward and then forward by word: PASS
Extend forward and then backward by word: PASS
Extend backward and then forward by line: PASS
Extend forward and then backward by line: PASS
Extend backward and then forward by paragraph: PASS
Extend forward and then backward by paragraph: PASS
unix:
Extend backward and then forward by word: PASS
Extend forward and then backward by word: PASS
Extend backward and then forward by line: PASS
Extend forward and then backward by line: PASS
Extend backward and then forward by paragraph: PASS
Extend forward and then backward by paragraph: PASS