You're right :) Corrected.

The instruction says: 'If hash does not contain at least one of the key given as an argument, method should raise an exception.'. In the test I gave two keys: one is correct (it is present in the hash), the second is not present in the hash. So at least one of the given key is not present in the hash. I don't see error in the description. Do you think that description:

'If any of the keys given as an argument is not present in the hash, the method should raise the an exception'.

will be more clear?

hh9 - it's really not so easy to create kata and make it clear for everyone. I see that you haven't create any yet. Please try and you will see :)

Thank you! I'm glad you like it :)

Agree. It makes more sense this way.

I think something is really wrong with your tests. Please, look at this screenshot (white outputs are call of puts method in Ruby with date attribute):

https://www.evernote.com/shard/s140/sh/bd5f4c22-32aa-4bb9-a21b-a259d329d6e9/435bdfcbd59ee260d6cf2b2fe555404a

'December 25 0002'

is rather not correct date :(

Yes, you're right. It was sandbox error.

Can I use the lambda to make closure ? My solution uses lambda. On my local machine, the test passes (I uses codewars framework) but it does not seems to work in codewars website :(

Yes,
for JS/CoffeeScript: Test.expectError(msg, fn)
for Ruby: Test.expect_error(msg, &block)

It works for my tests but for author tests I still get this error :(

True. Corrected :)