Add tests

[xepozz]

Need to cover each functionality with test.

Unit:

• [ ] Tests for raw data => object transformation
  • [ ] Post
  • [ ] Comment
  • [ ] Reactions
  • [ ] Vote
• [ ] Tests for caching mechanism

Acceptance:

• Posts
  • [ ] Posts is loading
  • [ ] Single post is loading
  • [ ] Comments is loading
  • [ ] Likes/Dislikes is loading
• Filtering
  • [ ] Filters by tag is working
• [ ] Caching is working
• [ ] Auth token can be stored