Install libvulkan-dev + mesa-vulkan-drivers (lavapipe = software Vulkan, no GPU needed) and stop passing CMAKE_DISABLE_FIND_PACKAGE_Vulkan so the Vulkan backend and its tests are built and exercised.
Install libvulkan-dev + mesa-vulkan-drivers (lavapipe = software Vulkan, no GPU needed) and stop passing CMAKE_DISABLE_FIND_PACKAGE_Vulkan so the Vulkan backend and its tests are built and exercised.