hset stores object as JSON instead of object.toString()

[LasTshaMAN]

I'm using redis-mock to write integration tests with Redis. In fact, I run two integration tests: one with real Redis client and another one with redis-mock.

When I try to do something like this:
redisClient.hset(collection_name, key, myJsonObject, callback);
I get discrepancies in the behavior between real Redis and redis-mock.

Namely, real Redis client converts my myJsonObject to string representation by calling myJsonObject.toString() while redis-mock client stores myJsonObject as an original JSON/JavaScript object.
So, when I retrieve myJsonObject back, with real Redis I get something like this "[object Object]", but with redis-mock I get the "original" JSON/JavaScript object as is (as it was inserted in).

So, the problem is: why redis-mock stores myJsonObject as is instead of storing myJsonObject.toString() ?