Seems there are leaks and possibly races running the tests
$ valgrind cmake-build-debug/bin/miral-test
...
[ FAILED ] 2 tests, listed below:
[ FAILED ] WindowProperties.on_creation_default_shell_chrome_is_normal
[ FAILED ] WindowProperties.on_creation_client_setting_shell_chrome_low_is_seen_by_window_manager
2 FAILED TESTS
==4566==
==4566== HEAP SUMMARY:
==4566== in use at exit: 30,210 bytes in 52 blocks
==4566== total heap usage: 245,664 allocs, 245,612 frees, 103,628,888 bytes allocated
==4566==
==4566== LEAK SUMMARY:
==4566== definitely lost: 96 bytes in 6 blocks
==4566== indirectly lost: 240 bytes in 6 blocks
==4566== possibly lost: 0 bytes in 0 blocks
==4566== still reachable: 29,874 bytes in 40 blocks
==4566== suppressed: 0 bytes in 0 blocks
==4566== Rerun with --leak-check=full to see details of leaked memory
==4566==
==4566== For counts of detected and suppressed errors, rerun with: -v
==4566== ERROR SUMMARY: 55 errors from 6 contexts (suppressed: 0 from 0)
$ valgrind cmake-build-
...
[ PASSED ] 111 tests.
==5090==
==5090== HEAP SUMMARY:
==5090== in use at exit: 30,210 bytes in 52 blocks
==5090== total heap usage: 245,605 allocs, 245,553 frees, 103,621,077 bytes allocated
==5090==
==5090== LEAK SUMMARY:
==5090== definitely lost: 96 bytes in 6 blocks
==5090== indirectly lost: 240 bytes in 6 blocks
==5090== possibly lost: 0 bytes in 0 blocks
==5090== still reachable: 29,874 bytes in 40 blocks
==5090== suppressed: 0 bytes in 0 blocks
==5090== Rerun with --leak-check=full to see details of leaked memory
==5090==
==5090== For counts of detected and suppressed errors, rerun with: -v
==5090== ERROR SUMMARY: 55 errors from 6 contexts (suppressed: 0 from 0)