Clean up some tests

[felixdivo]

This:

• roughly cuts the changed code length in half,
• is much more readable thanks to async code,
• uses strict comparisons,
• has better error messages/test titles,
• is less duplicated, and
• does not really change what is tested.

Closes #731

[coveralls]

Coverage remained the same at 91.515% when pulling c872494a102d0564fc5cef95957a1951a13e80b1 on felixdivo:rewrite-tests into b09a171b9a97756a79ea93bcc383dfcf2fbe3c5c on RobotWebTools:develop.

[felixdivo]

Hm, strange. I think this is done, but there's this error: FATAL ERROR: v8::ToLocalChecked Empty MaybeLocal. on CircleCI and AppVeyor. Has it appeared before? And Travis is failing too, but seemingly unrelated.

[wayneparrott]

@felixdivo I took a quick look and think the problem might be at line 55 in test-logging.js.

My reasoning is that the code where the exception is occurs is:

// preprocess Context
  RclHandle* context_handle = RclHandle::Unwrap<RclHandle>(
      Nan::To<v8::Object>(info[0]).ToLocalChecked());

[minggangw]

Hi @felixdivo would you please create the corresponding issues for this PR and #726, so we could track through issue<->pull request, thanks!

[minggangw]

My reasoning is that the code where the exception is occurs is:

// preprocess Context
  RclHandle* context_handle = RclHandle::Unwrap<RclHandle>(
      Nan::To<v8::Object>(info[0]).ToLocalChecked());

That's right, we have to pass an instance of Context as the 1st parameter.

[felixdivo]

Thanks @wayneparrott! It was exactly there. I was fooled by the default value for the context parameter, which (somewhat obviously) isn't used when passing an argument. It's now fixed. I'll check if the rest now works.

[felixdivo]

would you please create the corresponding issues for this PR and #726

Done.

And this PR is ready for a review.