M-b does not work the way it works in readline

[louwers]

test/test/test
             ^

Press M-b

Expected result:

test/test/test
          ^

Actual result:

test/test/test
^

[Asheq]

It's working for me. What happens when you type b to go back a word in normal-mode?

What is your iskeyword value? Type :set iskeyword?

EDIT: I realized that it works for me only in insert-mode but not in command-line mode.