Issue :

• python new test frame work is required.

Suggestion :

• remove unecceary comments in full tests suite
• assertion messages for tests

Is that a suggestion? Because there are only 2 languages (JS and Python), and both of them have easy ways to print to stdout. What you're saying makes no sense.

Way too easy is not an issue ;-)

Not an issue

The code have been enclosed.
Thank you for you input.

• For the sample test cases i modified some of them to have an odd number.
• I rededuced the size of input and increased the number of random tests.
• Thank you for you input.

This and this will show you the reason

EDIT: I already solved it but somehow my solution is not displayed (it always happen)

("...yet another Caesar cipher kata...")

Well, not so "yet another". At least there is a twist. ;)

Some issues, though:

• as said below: don't use test.expect (some readings here) (note: seemed to be already addressed?)
• you have to provide some tests with an odd length (both in the fixed aand the sample tests)
• lengths of the inputs in the random tests are ridiculously big!! There's no point to this, so you should reduce their length to something like 100 or 200 characters max (100 would be far enough, IMO).

I suggest also adding encryption ponctuation using pontuation list: for example in the set [",",";",":","?","!"," ","."] with a shifting of 5 "!" becomes ":"