(Improvement) Add tests and increase the coverage

[garatortiz]

• What is it? (leave one option)

  • (Improvement) of existing functionality

• What was the root cause of the problem originally / what feature was missing? The value of the coverage was less than 80%

• How does this pull request solve it (in broad terms)? Increases the value of the coverage

• Does it close any open issues? NO.

• Quick checklist

  • [x] npm run lint shows no errors
  • [x] docs were updated where necessary OR they don't need to be updated
  • [x] tests were updated where necessary OR they don't need to be updated

• Additional information

[phahulin]

@matiasgaratortiz maybe make travis install redis before running tests?

[coveralls]

Pull Request Test Coverage Report for Build 257

• 0 of 0 (NaN%) changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+5.5%) to 73.991%

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Totals
Change from base Build 246:	5.5%
Covered Lines:	791
Relevant Lines:	1025

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💛 - Coveralls