Use Qt${QT_MAJOR_VERSION} here too

src/tests/CMakeLists.txt

-find_package(Qt5Test ${QT_MIN_VERSION} REQUIRED)
+find_package(Qt${QT_MAJOR_VERSION}Test ${QT_MIN_VERSION} REQUIRED)
 
 add_executable(movetest movetest.cpp movetest.h ../move.cpp ../move.h)
 add_test(NAME movetest COMMAND movetest)
 
-target_link_libraries(movetest Qt::Test)
+target_link_libraries(movetest Qt${QT_MAJOR_VERSION}::Test)