The CI has $HOME=/home/jenkins/ with a trailing slash, which leads to
FAIL! : KConfigTest::testPath() Compared values are not the same

Actual   (sc3.readPathEntry("homepath", QString())): "/home/jenkins//foo"
Expected (HOMEPATH): "/home/jenkins/foo"

The fix is to also replace the '/' in "$HOME/", when the env var ends
with '/' and there is indeed a '/' after the env var in the source
string.

kconfigtest now passes with HOME=/home/dfaure/, and the newly
added unittest passes.