ok 12 - expr -a+b
ok 13 - expr 1/a
ok 14 - expr a.b
not ok 15 - expr a/b # TODO
#   Failed (TODO) test 'expr a/b'
#   at t/expr-stringify.t line 58.
#          got: 'a.(1/b)'
#     expected: 'a/b'
ok 16 - expr a.(1/b)
ok 17 - expr (1/a).b
ok 18 - expr a^2

##</code><code>##

ok 12 - expr -a+b
ok 13 - expr 1/a
ok 14 - expr a.b
not ok 15 - expr a/b # TODO
ok 16 - expr a.(1/b)
ok 17 - expr (1/a).b
ok 18 - expr a^2