Appendix 4
Generator Reference
(page 452)

The table has description about utf8() generator:

Generates to utf8-encoded text as a binary data structure.

Unfortunately, PropEr API do not has this generator. Link to documentation of PropEr API - link.

Link to unit() generator documentation - link. Link to vector() generator documentation - link. There are the closest places where documentation of utf8() generator could be.

Check if any generator is present in PropEr API, like integer() or tuple() via console:

lists:keyfind(integer, 1, element(2, lists:keyfind(exports, 1, proper_types:module_info()))).
{integer,2}
lists:keyfind(tuple, 1, element(2, lists:keyfind(exports, 1, proper_types:module_info()))).
{tuple,1}

Check if generator utf8() is missing in PropEr API via console:

lists:keyfind(utf8, 1, element(2, lists:keyfind(exports, 1, proper_types:module_info()))).
false

Note that, the console should be lounched in pbt project folder, which was created in the Chapter 1.

proper_types src.