"extensively test" is correct and usable in written English.
You can use it to emphasize the amount of testing or evaluation that has gone into something. For example, "Before the new software was released, it was extensively tested to ensure its reliability."
Mr. Harvey said that he could not afford to hire an outside firm to extensively test the effectiveness of his products, but that he tested them himself with most of the popular smartphones and major wireless carriers.
This is probably the most time-consuming of all the steps since they have to extensively test the update, and the process can differ from carrier to carrier.
This tool can extensively test the conformational space of fusion proteins and finally generate plausible models [351].
Further, we implement the proposed framework and extensively test it on both a simulated environment and on a real cloud.
The main objective of the research was to extensively test the effect of the sugar reform on VPT and on concentration and competition within the EU.
However, explicit, experimental utilization of molecular distribution data to update kinetic constants and to extensively test mechanisms utilizing current theoretical descriptions is, perhaps, insurmountable, or at least foolhardy.
"There's Something About Mary" was extensively test-screened, and, Mr. Pollock says, "Each big laugh translated into about $20 million".
And Ms. Fuller is concentrating on developing The Star, a celebrity-oriented newspaper tabloid that will be extensively test-marketed as a glossy magazine in the coming months.
It's an extensively tested engine, very robust and rugged.
There are certain antibiotics that have not been extensively tested.
Thomas & Friends past production has been extensively tested and re-tested to assure safety.
