commit f63951d5e1b0975ddd40b679a2bf5c64e7d0431e
author Daniele Di Proietto <ddiproietto@google.com> Mon Oct 07 13:59:50 2024 +0000
committer Daniele Di Proietto <ddiproietto@google.com> Mon Oct 07 14:12:51 2024 +0000
tree 613c82d2768904058227ce2c61cbe66a0a323691
parent 3d3de5af2d068c6a331f4984a0d0d6a67fe91d2c

tracing_service_impl_unittest: Avoid internals in ScrapeOnDisconnect

This test is trying to simulate what happens with a remote producer when
it disconnects. The test however uses an in-process producer.

An in-process producer behaves quite differently (compared to a remote
producer). The shared memory arbiter (and the shared memory itself) is
owned by the producer endpoint. There's no way of disconnecting an
in-process producer without destroying its shared memory arbiter. But we
cannot destroy the shared memory arbiter, because the trace writer holds
references to it. We cannot destroy the trace writer, because it would
flush, and scraping will not be exercised.

This commit makes the test more realisting by using a "remote" producer:
* Producer `in_process` can be set to false.
* TestRefSharedMemory is a new type of shared memory that can be used to
  simulate two components having access to the same shared memory in
  tests.
* In order to simulate a disconnection, a ProxyProducerEndpoint can be
  configured to forward all the requests to a real proxy or to drop
  them, after disconnecting.

The test can now own the shared memory arbiter. TracingServiceImpl will
behave as it does with a remote producer and scrape its memory.

+ The production code doesn't contain test only code.
- There's a lot more test-only code required.
+ The test is more realistic.

Change-Id: I61121c6623f912c167876602e93ead39cd087c52