Testing rhymes with:
attesting, contesting, protesting, retesting, arresting, attesting, besting, breasting, contesting, cresting, digesting, divesting, ingesting, investing, kesting, molesting, nesting, protesting, reinvesting, requesting, resting, retesting, suggesting, vesting, wresting
Testing sounds like:
tajikistan's, tastiness, tasting, tastings, techsystems, tectonic, tectonics, testimonies, thaxton's, ticketing, tightening, tightenings, tightens, tightness, toasting, touchdowns, twisting