[TEST] Allow using other JSON libraries in tests
[TEST] Allow using other JSON libraries in tests

Use the `JSON_LIBRARY` environment variable to load a specific JSON library:

    $ JSON_LIBRARY=oj ruby -I lib:test test/integration/multi_search_test.rb

brijeshgpt7/retire,alphagov/tire,elbuo8/retire,iamrahulroy/retire,mavenlink/retire,fabn/retire,karmi/retire,Telmate/tire,tklee/tire_shiphawk,dbose/retire,1776/tire,doximity/tire,rubydubee/retire,zaharpecherin/retire,ChapterMedia/tire,HenleyChiu/tire