diff: restore original color scheme for worddiff I'm not young. "red dim" is nearly invisible, and "red" vs "red dim" is too subtle to see difference. And, "underline" is necessary to highlight whitespace changes.

test-fix: fix use of 'f --newer' to check that foo.whole is not updated Here we want to assert not 'mtime(foo.whole.orig) < mtime(foo.whole)'. The condition has to be inverted since 'f --newer' says "newer" if the mtimes match. Alternatively, we could insert 'sleep 2' before 'cp' to ensure that foo.whole.orig is newer than foo.whole, but a fewer sleeps should be better.