While there are many fine Code trainers out there, I really liked a program called DMorse. It teaches the Code in bite-sized pieces, then will generate random strings of characters to test you.
The random strings are quite helpful -- no context, as in the Code tapes to have you anticipate the next letter.
And, it's free.http://www.glenfieldho.freeserve.co.uk/morse.htm
It runs in a DOS window. Give it a try.
GL with it.