rubyx/test/parser/README.markdown

Parsing

Some sanity is emerging in the testing of parsers (Parsers are fiddly in respect to space and order, small changes may and do have unexpected effects)

Parsing is a two step process with parslet:

• parse takes an input and outputs hashes/arrays with basic types
• tramsform takes the output of parse and generates an ast (as specified by the transformation)

A test tests both phases seperately and again together. Each test must thus specify (as instance variables):

• the string input
• the parse output
• the transform output

Test are grouped by functionality into cases and define methods parse_* Test cases must include ParserHelper, which includes the magic to write the 3 test methods for each parse method. See test_basic ofr easy example.