Revert "Merge branch 'master' into available_shifts"

This reverts commit 5baac8a69a67ccca75fb70c0b33ac5efdc0e32bb, reversing
changes made to 615920ab342d773e303ab434e76afc14f5584392.
Revert "Fixed some failed tests"

This reverts commit 615920ab342d773e303ab434e76afc14f5584392.