fix: ElectronExternalApi fallback to super when electron app is undefined, fixes #399

[douglascayers]

Background

Fixes #399

Changes

• Update ElectronExternalApi.getAppName() and ElectronExternalApi.getAppVersion() to fallback to super method just as when catching an error if electron.app is undefined
• Inject electron into api class to help with testing and mocking scenarios
• Add tests for ElectronExternalApi class

[megahertz]

Thank you, @douglascayers. The PR looks good! I would only prefer to pass electron as an argument of the ElectronExternalApi constructor instead of mocking in tests. I'm able to make that change this weekend, or you can make that change by yourself.

Something like that:

const electron = require('electron'):
...
const externalApi = new ElectronExternalApi({ electron });

[douglascayers]

I would only prefer to pass electron as an argument of the ElectronExternalApi constructor instead of mocking in tests

Good with me! That would make the test much easier to stub the electron props and avoid need for testdouble.

I'm able to make that change this weekend, or you can make that change by yourself.

Thanks, I'll adjust the PR.

[douglascayers]

@megahertz I've refactored the changes -- much easier to test using dependency injection 😄

Ready for your review again, thanks

[megahertz]

Thank you @douglascayers. It looks great! I will try to merge it tomorrow morning.