Unbeaten in three runs over fences, he holds four other entries but McCain is favouring the handicap route at this stage, despite him being shouldered with top weight.
Testify enjoyed a spin around Southwell before racing on Friday, working alongside Grand Annual contender Katachenko and Lofgren, who is entered in the National Hunt Chase.
"We came here just to get them away. We've been cantering away at home but I can't get any work into them as we're frozen," McCain told At The Races.
"If you want to go to the festivals, you have to do that little bit extra which is what we are doing.
"It's not a strong piece of work. Testify is a staying chaser so they've just gone steady. They are good lads who know exactly what they are doing and hopefully they are all fine in the morning.
"We've then got a week of hopefully not panicking. The one thing we are a long way behind Ireland in is the amount of schooling bumpers and what have you they have on racecourses. As this is an all-weather surface, they are not precious about ground.
"He's got five entries and Mr (Trevor) Hemmings (owner) is not putting me under any pressure to choose, but the Close Brothers looks the obvious one because it looks like being a small weight range with the top ones going for the JLT missing.
"He's a nice, young horse and we've had him all the way through.
"He's won his three novice chases. He surprised us by winning twice over two miles and we were always going to step up to two and a half. In time he'll want three, but at the moment we'll stick to two and a half."
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