All I mean is that commas are fine in csv files as long as they occur inside quotes. Otherwise they are interpreted as column separators. I think Intro to R is fine in this respect; answer test entries are always quoted.

For instance, mod3_new.Rmd, line 194 specifies a series of tests as follows.

is_a=character, my_name; uses_func=c; creates_var=my_name; val_length=4

The line contains a comma and there are no explicit quotes, but when the corresponding csv file is built, the AnswerTests entry (question 29) is automatically quoted.

"is_a=character, my_name; uses_func=c; creates_var=my_name; val_length=4"

The newtests1 branch would require the Rmd line to be something like:

var_is_a(e, 'character', 'my_name'); expr_uses_fun(e, 'c'); expr_creates_var(e, 'my_name'); val_has_length(e, 4)

So we have commas and quotes. If, when the csv file is built, we end up with 

"var_is_a(e, 'character', 'my_name'); expr_uses_fun(e, 'c'); expr_creates_var(e, 'my_name'); val_has_length(e, 4)"

everything is fine. I think double quotes in the Rmd line are also OK, since they will be escaped when read. If escaped quotes, rather than single quotes, were used in the Rmd line itself, i.e.,

var_is_a(e, \"character\", \"my_name\"); etc.

there could be trouble.

We ran into problems of this general sort with the test modules, which were created manually, so it seem reasonable to sound a cautionary note.