For testing of the citeproc-js utility (used in Zotero and Mendeley
bibliography managers), I use the DOH test framework from the Dojo
project. When running code in Rhino (or other standalone interpreter
such as jslibs/jshost), It provides a command-line test environment,
similar to that used in Python and other scripting languages. For
citeproc-js development I wanted to have a rapid command-line testing
cycle, and DOH has worked out quite well for that.