test: fail tests in case of unhandled errors

[pi0]

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

Currently, we have some unhandledPromiseRejections which are uncaught!

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly. (PR: #)
• I have added tests to cover my changes (if not applicable, please state why)
• All new and existing tests are passing.

[codecov-io]

Codecov Report

Merging #5255 into dev will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              dev    #5255      +/-   ##
==========================================
+ Coverage   95.98%   95.99%   +0.01%     
==========================================
  Files          74       74              
  Lines        2490     2497       +7     
  Branches      630      633       +3     
==========================================
+ Hits         2390     2397       +7     
  Misses         84       84              
  Partials       16       16

Impacted Files	Coverage Δ
packages/cli/src/command.js	98.97% <100%> (+0.07%)	⬆️
packages/vue-renderer/src/renderer.js	94.38% <0%> (-0.52%)	⬇️
packages/cli/src/commands/generate.js	100% <0%> (+5%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2561b68...1394b09. Read the comment docs.