The phrase "hours of tests" is correct and usable in written English.
It can be used to describe a duration of time spent on testing, often in academic or professional contexts.
Example: "After hours of tests, the students finally received their results."
Alternatives: "lengthy testing sessions" or "extensive test duration".
And unlike Aquila, the Amber rarely crashed, suffering just one accident in 650 hours of tests.
Two summers ago, a whole team of researchers came and did a couple hours of tests of with my oldest daughter and me.
They are free to enter but horribly difficult, involving three hours of tests which cover everything from maths and reading to verbal and non-verbal reasoning.
Since the project started in 2009, Google has driven most of its 1.2m hours of tests in a small fleet of customised Lexus autonomous cars.
After nearly three hours of tests, we were handed a topic and told we had 20 minutes to write an essay.
Hayaschi required Johnson to undergo a CAT scan, a brain wave test and four hours of tests involving memory and motor skills before fighting again.
I was told that Gears 2 would be subject to roughly forty thousand hours of testing before its release.
He lost consciousness, went to a hospital in an ambulance and had more than nine hours of testing.
More than 100 hours of test flights have been carried out using the unmanned aerial vehicle developed by AVIC Aerospace, a subsidiary of the Aviation Industry Corp of China.
To qualify for installation, a new engine undergoes several hundred hours of testing that embraces the entire intended range of speed and altitude capacity of the airplane.
"The Volt needs a better engine," said Mr. Johnson, adding that 1,600 hours of testing had shown Achates's engine was 15 percent more efficient than conventional diesel counterparts.
