Let's say I am in chromium and I build media_unittests:
$ ninja -C out/Default -j 200 media_unittests

Then I run them with a filter so only one will run: 

$ out/Default/media_unittests --gtest-filter=FFmpegDemuxerTest.Read_DiscardDisabledTextStream

If I misspell the flag as I did above, "gtest-filter" instead of "gtest_filter", then the test prints out the flags listing and then runs the tests and has a bunch of errors such as "no test result for AudioRendererAlgorithmTest.QuadraticInterpolation_Colinear". This is very specific. If I run

$ out/Default/media_unittests --gtest
or
$ out/Default/media_unittests --asdfasdfas

Then it prints the flags and then runs the tests without errors. But if I run 

$ out/Default/media_unittests --gtest-
or
$ out/Default/media_unittests --gtest-asedfgsd

Then it prints flags and then runs the tests and has a bunch of errors. So somehow the dash is important.

Two things:

1. If a flag is misspelled, then it's probably better *not* to run the tests because probably something is missing that was intended.

2. Why does that specific misspelling have that specific result?

Sorry if this is the wrong bug queue for this. Perhaps it is an issue with https://github.com/google/googletest