cover exit-challenger with unit tests

[roleengineer]

Bounty

Cover exit-challenger with unit tests

Scope

• write unit tests
• write init function (instead of using global variables)

Deliverables

• updated tests
• refactoring

Funding Circle

Dev Circle.

Bounty Owner/Gardener

@roleengineer as Tool Engineer

Gain for the Role

Challenge-services tests coverage will be increased.

Roles

bounty gardener: @roleengineer / X DAI
bounty worker: @roleengineer / share
bounty reviewer: name / share

Gardener checklist

• I have attached one of the size- labels to this bounty
• I have submitted this bounty via http://bounty.leapdao.org/viewform
• I have added this bounty to bounty board here https://github.com/orgs/leapdao/projects/6