There is a race between "close" event coming from the server and
"close" command issued from the client.
This is similar to calling close after disconnect, so added tests.
- Print parentGuid when it is not available for __create__.
Some bots show generic "something is undefined" error - let's
get better information about the failure.
- Ignore events on disposed objects outside of tests.
Some bots show this happening for "previewUpdated" - let's see
whether there are more important events that misbehave.
This introduces basic tracing enabled in our tests.
What is captured:
- network resources;
- snapshots at the start of most actions;
- snapshot after the test failure.
How this integrates with test runner:
- context fixture calls private method context._initSnapshotter() and uses Tracer to trace all events;
- all tests share a single test-results/trace-storage directory to store blobs;
- each test has its own trace file.
- npm run show-trace opens a bare-minimum trace viewer that renders snapshots.
