When debugging an issue with failing rendertest for kdepim-addons I realized, that the issue is, that on ci images there is no Breeze color schema available. If I run QStyleFactory::keys() for my normal system/neon system. I get:
("Breeze", "Windows", "Fusion")
for the CI images I get:
("bb10dark", "bb10bright", "cleanlooks", "gtk2", "cde", "motif", "plastique", "Windows", "Fusion")
I fixed the issue now to make sure that tests are run with the Fusion color schema - but IMO it makes sense to have at least the option to test with breeze style.