Show correctly the values of hash and none type on stats tab

[mishina2228]

The keys and values of Redis can be checked in Resque Stats tab.
resque-scheduler registers hash type value on Redis for persistent schedules data.
However, when I try to display the value, it raises an error.

• persistent_schedules is a hash. Its size is not shown.
  
• Error after clicking the key
  

This PR will solve this problem.

• persistent_schedules' size is shown.
  
• After clicking, we can see the value.
  

In addition, this PR corrected the case where the type is none.
#redis_get_size used to return an empty array([]), but it should return 0 here.

[mishina2228]

HGETALL has a noticeable performance problem when the size of the hash is large.
https://redis.io/commands/hgetall/

Time complexity: O(N) where N is the size of the hash.

We do not expect to use such large hashes in Resque, so I use HGETALL here.

[PatrickTulskie]

@mishina2228 hey just going through things here getting caught up. I know it's been a while, but do you think you can rebase your branch and add a test for your change?

[mishina2228]

I'm trying to add tests but it could be tough. 😅
To test the methods in the helpers block, it appears that the code in the block needs to be cut out into a module.
https://stackoverflow.com/questions/2878818/how-can-i-test-helpers-blocks-in-sinatra-using-rspec

[PatrickTulskie]

I'm trying to add tests but it could be tough. sweat_smile To test the methods in the helpers block, it appears that the code in the block needs to be cut out into a module. https://stackoverflow.com/questions/2878818/how-can-i-test-helpers-blocks-in-sinatra-using-rspec

Ah okay maybe not worth it in that case then. I think we should be good as-is.

[mishina2228]

Thanks! 🙇