Add tests for `CreateViper` and `ReloadViper` to ensure that no extra
files, except *.yaml, *.yml, *.json, are loaded from config directory.
Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>
`fmt.Errorf can be replaced with errors.New` and `fmt.Sprintf can be replaced with string addition`
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
