Merge branch 'sk/unit-tests-0130'

Convert a handful of unit tests to work with the clar framework. * sk/unit-tests-0130: t/unit-tests: convert strcmp-offset test to use clar test framework t/unit-tests: convert strbuf test to use clar test framework t/unit-tests: adapt example decorate test to use clar test framework t/unit-tests: convert hashmap test to use clar test framework