test: added tests to ensure correct uglify-es version is being used.

[hulkish]

Fixes #67 (comment)

[joshwiens]

Attack of the modules .... again ! :p

[hulkish]

Jeez, i guess i was incorrectly assuming the uglify-es version as the cause. what does this print out for u?

node -v
npm -v
cat node_modules/webpack/package.json | grep version
cat node_modules/uglify-es/package.json | grep version
cat node_modules/uglify-js/package.json | grep version

[joshwiens]

[hulkish]

@d3viant0ne can u try installing npm >= 5? I suspect it's related to package-lock.json not being respected. Because we have [email protected] in our package-lock.json, but your version is printing 3.0.23

Another solution maybe we upgrade to [email protected]? Although... the npm version bump would still be needed.

[michael-ciniawsky]

It sometimes works locally (macOS) for me, but the test are definitely flaky. But what is this test actually testing here ? 🙃

[hulkish]

@michael-ciniawsky the test in this PR is not actually intended to be merged. Just an attempt to find the cause of this issue.