I've done some digging around, and in fact @rmandelb is the author of this script, and it was written for Issue #384 , related to this PR, opend 7 months ago by @tomaszkacprzak , and which still remains open.  The last comment Rachel made was this one: https://github.com/GalSim-developers/GalSim/issues/384#issuecomment-16986691

... which received no response.

Are HSM runtime errors still a problem for this branch Tomek?  Can #384 be closed now?

Another, perhaps easier to ask question, is whether or not `test_convergence.py` actually belongs on this branch and Pull Request.  If your tests ran without it Tomek then I think it may be better to make sure that #384 has the most up-to-date version of this module `test_convergence.py` and simply delete it from this branch, where it is something of an incongruous addition.