Unit tests incompatible with `qt5ct` or `qt5-style-plugins` #630

I installed qt5ct and qt5-style-plugins to change the Bitcoin Core theme (master branch) on Ubuntu 21.10. If I change Ubuntu to dark mode, Bitcoin Core does not change. So most of the answers in this reddit post suggest installing qt5ct and qt5-style-plugins and it worked.

I was able to successfully compile and run the executable (including changing the theme), but running make check failed without a detailed error:

../build-aux/test-driver: line 112:  5085 Aborted                 (core dumped) "$@" >> "$log_file" 2>&1
FAIL: qt/test/test_bitcoin-qt

And in the src/test-suite.log file:

(gdb) === End of stack trace ===
QFATAL : AppTests::appTests() Received signal 11
         Function time: 315ms Total time: 315ms
FAIL!  : AppTests::appTests() Received a fatal error.
   Loc: [Unknown file(0)]
Totals: 1 passed, 1 failed, 0 skipped, 0 blacklisted, 581ms
********* Finished testing of AppTests *********
FAIL qt/test/test_bitcoin-qt (exit status: 134)

It's certainly not a critical error but I thought it best to report it anyway.

https://github.com/bitcoin/bitcoin/pull/16366#issuecomment-511117287

I tried QT_LOGGING_RULES="qt5ct.debug=false" make check and BITCOIND=bitcoin-qt QT_LOGGING_RULES="qt5ct.debug=false" make check but the error persists.

If the qt5ct is removed, make check works again.

Closing due to recent upgrade to Qt 6.

Feel free to reopen with updated details.