Assertion failed in TestStrings.cpp

Hi,

I am trying to run FuzzManager to some fuzzing of Firefox.

I cloned and compiled Firefox using this config:
mozconfig.txt

Then to instrument the DOM I used the following instead of /dom/moz.build:
moz.build.txt
However, the the fuzzy test case is defined with the required functions (but they are empty)

Then I cloned FuzzManager, installed the server dependencies, installed it with the setup.py install.

Then, I run the server with python manage.py runserver from the /server/ folder.
Finally, I run the fuzzer with the following command, as suggested here:

MOZ_RUN_GTEST=1 LIBFUZZER=1 FUZZER=Dom python ~/FuzzManager/misc/afl-libfuzzer/afl-libfuzzer-daemon.py --fuzzmanager     --stats libfuzzer-dom.stats --libfuzzer-auto-reduce-min 500 --libfuzzer-auto-reduce 30     --tool libfuzzer-dom --libfuzzer --libfuzzer-instances 6 ~/mozilla-central/objdir-ff-asan/dist/bin/firefox     -max_len=256 -use_value_profile=1 -rss_limit_mb=3000 corpus-dom

And this is the stderr and stdout I get:

out.txt
err.txt

Could you help me to understand why the assertion is failing? Shouldn't that go through without errors?
Can I use the FuzzManager in a way I can exclude all the other tests and run only a list of tests?
How to run only one test fuzzer?

Thanks!

Start with the assertion named in TestStrings.cpp, then compare the attached out.txt and err.txt with the Firefox build and fuzzing command shown here. Verify whether the failure comes from the instrumented DOM setup or the FuzzManager daemon, and determine how a single selected fuzzer or test can be run. Done means the assertion cause and supported selective-run procedure are documented.