TEST_DEPENDS can be silently ignored
A VTK module with a TEST_DEPENDS that is not provided by VTK will just see the tests being disabled silently. eg:
eg:
find_package(VTK 9.0 REQUIRED
COMPONENTS
FiltersGeneral
FiltersGeometry)
NAME
myModule
PRIVATE_DEPENDS
VTK::FiltersGeneral
TEST_DEPENDS
VTK::TestingCore
The module will build fine but the tests will not be, without any explanation.