BETWEEN condition not validating properly
There is an error in the validation of the BETWEEN condition, which needs two values (start, end) and not one.
I have forked dynamodb-mock in my GitHub because I needed this fixed quick. To make things easier for you, here is the commit https://github.com/dekked/dynamodb-mock/commit/1f02c4b9659d0a5f84625250fd2795a4916ee7d1 where you can check out the diff.
Hope you can incorporate this into ddbmock soon :)