'timeless testament' is correct and usable in written English.
It is a form of metaphor which is used to convey a sense of something that is timeless and lasting. For example: Her bravery is a timeless testament to the power of the human spirit.
A 1990 wine from Mr. Cerri shows what attracted Mr. Künzli to the area: It certainly shows signs of its age, but the velvety texture, spicy complexity and mouthwatering vestiges of red fruit are a testament to timeless winemaking and a beautiful terroir.
It's a testament to their timeless appeal, and aluminium's rust-resistant durability, that an astonishing 70percentnt of all Airstreams ever made are still on the road.
THE CROWD A testament to the timeless compatibility of wealth and attractiveness, PH-D is a crush of men in business-casual attire and women who rarely spend weekdays in an office.
In one respect, the staying power of the traditional degree is a testament to its timeless relevance, cultural meaning and professional utility.
A follow-up to the 2006 hit "Duets," the new collection features Bennett recording with a panoply of stars young and old, and it stands as a kind of implicit testament to his timeless, cross-genre appeal.
It's a real testament to how timeless this show is -- the set and situation look just as current today as they did when the show first debuted a decade ago.
Really, the fact that he got away with running seven-year-old footage, candid iPhone clips, and VX footage in an HD video is a testament to how timeless and unique his skating is.
Daniel Brockman of The Phoenix described "Radio" as the most believable song on the album, and complimented its "amid bland testaments to love's timeless endurance and the smut and thuggin[g] of the 'Sasha Fierce' persona, [which] is one with sensual overtones sung to an electronic device that, unlike men, 'never lets me down'".
The believability of the song's lyrics, which conveys love testaments as well as its timeless endurance, sung on sensual vocal arrangements by Knowles, who additionally adopts a sneering attitude, demonstrates her alter ego Sasha Fierce.
China's countryside has a rhythm all its own: ubiquitous squat buildings with blue glass windows and pink tile walls, testaments to China's rush to modernize, but also the timeless lives of the peasants.
