Your situation isn’t all that odd. Thousands of Companies from all over the world send their employees to the United States to conduct business daily. There is no such thing as “kind of research”. You are either conducting work (or business, and your testing would easily be classified as business), or you are not.
Whether or not you plan on doing some sight-seeing and travel during your free time is up to you, and doesn’t negate the fact that you are in the United States primarily to do testing and conduct business.
That leads to your next question about the Visa Requirements: It sounds like you and your colleagues will need a B1 Visa, not a B2 Visa.
From the Department of State website, a B-1 Visa is to be used to:
You will be doing the first as part of your testing. You are on company time, doing company work (testing, research), using company equipment, and consulting/communicating with work (company) colleagues.
Simply tell border agents the truth. Read more here. (PDF)
Credit:stackoverflow.com‘