For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ighvh:tumbleweed/openSUSE_Tumbleweed/home:ighvh:tumbleweed.repo
zypper refresh
zypper install rt-tests
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ighvh:tumbleweed/15.4/home:ighvh:tumbleweed.repo
zypper refresh
zypper install rt-tests
For 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ighvh:tumbleweed/15.3/home:ighvh:tumbleweed.repo
zypper refresh
zypper install rt-tests