"clear testament" is correct and usable in written English.
It means a declaration or statement that stands as conclusive proof of the truth of a specific point or fact. Example: His contribution to the project was a clear testament to his hard work and dedication.
"That's a clear testament to what's possible for Congo," Affleck said of the Starbucks purchase.
Located off Hamilton Hall's main lobby, the center is a vastly improved resource as well as a clear testament of the Core's central place in the College.
Gen. Josef Blotz, chief spokesman for the NATO-led International Security Assistance Force, called the high police casualty rate a clear "testament that the Afghan forces do sacrifice a lot for their country".
Simon Jenkins, a former editor of the Times and member of an inquiry into drugs and the law under Lady Runciman, argues that London's vibrant clubbing scene is clear testament to the profusion of drugs available there: how else would people have the energy to dance all night?Most drug users, like those clubbers, are occasional dabblers.
The longevity of the fluorescent cell sorter is a clear testament to its power, but subsequent years have also shown a need for complementary methods that can be applied for more specialized experiments — for example, sorting through dozens or hundreds rather than millions of cells, or plucking a handful of cells from a slice of brain tissue.
The overwhelming initial response is a clear testament to that.
The first clear testaments to Christian communities in Switzerland date after 313, when the religion was officially tolerated with the Edict of Milan.
Ultimately, isn't our democracy's proven ability to respond to, change through and absorb crisis the clearest testament to the enduring greatness of our country?
There is no clearer testament to the divorce of ideology from common sense than the position of House Republican leader John Boehner who calls for cutting $100 billion out of domestic discretionary spending next year -- nearly 15% of the total.
If Tiananmen Square is a monument to the Maoist policy of self-sufficiency, the Olympic Green, ten miles and fifty years away, is an architectural statement of intent every bit as clear — a testament to the global ambitions of the world's fastest-growing major economy.
I might be less clear on my New Testament than my Vogue.
