Yes, I've noticed this too and worked around it with --gtest_filter=* (or similarly --test-launcher-jobs=1 I think would work).

I didn't investigate whether it was general test launcher behaviour, or perhaps I wrote a bug in base/test or base/process as far as getting output redirected.

Seems that we tend to get one line of output from the sub-process, and then nothing more.

Sub-process output is redirected to a temporary file which the TestLauncher pulls the contents from, suggesting that the crashing sub-process may not be flushing correctly.

Output being logged is logged by base/logging, and is essentially fwrite(stderr, ...); fflush(stderr).

Output is then read back by TestLauncher using ReadFileToString(), which jsut open(..., "rb")s the file and fread()s its entire contents.

We're missing stderr from failing tests because the redirected-output file is missing all the stdout lines, preventing GetTestOutputSnippet from finding the individual test's output lines in the batches output.

This suggests a fault in the FD remapping of the Fuchsia LaunchProcess implementation, or the underlying launchpad APIs.

This looks like an edge-case (one parent FD mapped to two different child FDs) that the mxio __libc_extensions_init doesn't handle quite correctly - filed https://fuchsia.atlassian.net/browse/MG-985.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e5e63e607292ffc1bc65e35ee52f2612d462ee27

commit e5e63e607292ffc1bc65e35ee52f2612d462ee27
Author: Wez <wez@chromium.org>
Date: Fri Aug 04 18:48:53 2017

Open TestLauncher batch output files with O_APPEND

This works around a bug in LaunchProcess() under Fuchsia, which results
in a single seekable file FD mapped to multiple FDs in a target process
ending up with independent seek positions into the file, and writes to
the two FDs therefore trampling one another.

Bug:  751253 
Change-Id: I9d8538744ad7048b93c2ebaf49323b1d399e9510
Reviewed-on: https://chromium-review.googlesource.com/598696
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492088}
[modify] https://crrev.com/e5e63e607292ffc1bc65e35ee52f2612d462ee27/base/test/launcher/test_launcher.cc