The phrase "a stiff test for" is correct and usable in written English.
It can be used when describing a challenging evaluation or examination that someone or something must undergo.
Example: "The new software will face a stiff test for its performance during the upcoming trial period."
Alternatives: "a tough challenge for" or "a rigorous assessment for".
This is a stiff test for the press.
It's a stiff test for the Brit but it is also a great opportunity.
In the featured super-middleweight bout, Sam Hill was expected to provide a stiff test for the up-and-coming Jermain Taylor.
Getting the proposal through the opposition-controlled legislature will be a stiff test for the president, a political novice.Mr Martelly's biggest strength is his popularity.
– presents potential for discord, and steering his team through this adversity will be a stiff test for Ryan, perhaps the stiffest of his tenure.
In the Sonatine, the writing for piano, "the archetypal instrument of delirium", set the explosive pattern for later keyboard works, especially the Second Piano Sonata (1948), which is still a stiff test for the virtuoso: Olivier Messiaen claimed Boulez "totally transformed the sonority of the piano".
This year will be a stiff test of the president's credentials.
Mourinho believed Roy Hodgson's men were handed a stiff test when the draw for Brazil 2014 was made last year.
But there will be no apprenticeship for road haulage: the government says people should pay to get their own licences, though courses cost £3,000, plus a £230 fee for a stiff test which applicants often require several attempts to pass.
"He is furnishing by degrees, but whether he is quite ready for such a stiff test over a mile and a half I would not be certain about.
Clemson has been criticized in recent years for not handling success well, so this will be a stiff test.
