unit test coverage needed for Promise.reject handling in Runner

[thescientist13]

Type of Change

• New Feature Request
• Improvement / Suggestion
• Documentation
• Bug
• Other (please clarify below)

Summary

Improve unit testing coverage (primarily around error handling)

Details

coverage reports shows some area for branch coverage improvement in runner.js

------------|---------|----------|---------|---------|-------------------
File        | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
------------|---------|----------|---------|---------|-------------------
All files   |    92.5 |    76.92 |     100 |    92.5 |                   
 src        |     100 |      100 |     100 |     100 |                   
  index.js  |     100 |      100 |     100 |     100 |                   
 src/lib    |   92.11 |    76.92 |     100 |   92.11 |                   
  runner.js |   92.11 |    76.92 |     100 |   92.11 | 26,53,73          
------------|---------|----------|---------|---------|-------------------

=============================== Coverage summary ===============================
Statements   : 92.5% ( 37/40 )
Branches     : 76.92% ( 10/13 )
Functions    : 100% ( 10/10 )
Lines        : 92.5% ( 37/40 )
================================================================================

Mostly around handling instances of Promise.reject. Would love to get this above 90% 🤞