Problem: New style testing is incomplete.
Solution: Add the runtest script to the list of distributed files.
Add the new functions to the function overview.
Rename the functions to match Vim function style.
Move undolevels testing into a new style test script.
Problem: Writing tests for Vim script is hard.
Solution: Add assertEqual(), assertFalse() and assertTrue() functions. Add
the v:errors variable. Add the runtest script. Add a first new
style test script.