Add generic loading function and corresponding test

4 jobs for theo-gen-load in 18 minutes and 2 seconds (queued for 15 minutes and 6 seconds)
Status Name Job ID Coverage
  Build
passed build_linux_27 #127096
docker

00:09:37

57.0%
passed build_linux_36 #127097
docker

00:10:35

57.0%
passed build_macosx_27 #127098
macosx

00:18:02

57.0%
passed build_macosx_36 #127099
macosx

00:17:12

57.0%