In principle, VTS test cases are co-located with their respective projects.
HIDL HAL Tests: test/vts-testcase/hal/<hal name>/<version> and hardware/interfaces/<hal name>/<version>/vts
Kernel Tests: test/vts-testcase/kernel
LTP: external/ltp
Linux Kselftest: external/linux-kselftest
VNDK (Vendor Native Development Kit) Tests: test/vts-testcase/vndk
Performance Tests: test/vts-testcase/performance
Fuzz Tests: test/vts-testcase/fuzz
Security Tests: test/vts-testcase/security
The files under this directory (test/vts/testcases) are only for: VTS codelab, template, tests for legacy components, and tests that are under development and do not have any respective projects.