In doing this test marketing you should make a plan that will make you a success even if nobody comes along with their magic wand.
Start now. Don't wait for a “deal”.
Don't just record a “demo” that is meant only for record companies.
You have all the resources you need to make a finished CD that thousands of people would want to buy. If you need more money, get it from anyone except a record company.
And if, as you're following your great business plan, selling hundreds, then thousands of CDs, selling out small, then larger venues, getting on the cover of magazines... you'll be doing so well that you won't need a record deal.
And if a record deal IS offered to you, you'll be in the fine position of taking it or leaving it. There's nothing more attractive to an investor than someone who doesn't need their money. Someone who's going to be successful whether they're involved or not.
Make the kind of business plan that will get you to a good sustainable level of success, even without a big record deal. That way you'll win no matter what happens.