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 Job ID Name Coverage
  Build
passed #127096
docker
build_linux_27

00:09:37

57.0%
passed #127097
docker
build_linux_36

00:10:35

57.0%
passed #127098
macosx
build_macosx_27

00:18:02

57.0%
passed #127099
macosx
build_macosx_36

00:17:12

57.0%