heh, right... just to clarify a little: 

1. names like `_foo()` are private.  typically locals... Lua doesn't care about that convention, but i've used it at some places to make it evident that these aren't functions that can be called somewhere else.  In this specific snippet there are several local functions that are created just for the tests.  if they're too ugly i'm not against removing the leading `_`.

1.  `__setup()` is a function that runs before each other entry on the same group.

1. CamelCase vs. snake_case? again, no real preferences.  `sf_to_vf` seems shorter than `SingleFunctionToVirtualFunction`.  Not sure which looks better in the report...

1. tables in the form `xxx_mt` are usually metatables, but i'm not sure i've used that too frequently here...