Is he testing me?

From my view all I can see is he want a future with you, nothing more doesn't sounds like a test to me unless he had some kind of questioning emotion when he ask.

He didn't say anything about asking her old girlfriend's money back, so to me he's not testing you about money. Having second job could means he want a back up money for your and his future(like marriage) in case if anything happen to his very successful business.

Almost all guy who truly love his woman would want to "take care" of them rest of his life, that could be the reason why he said if you need money he can give it to you.

Sounds like he's doing both. He's testing you to see your true attitudes about money, and at the same time he's testing the water on the potentiality of a possible relationship. Nothing wrong with that, he just wants to see how you really feel about issues like finances and possibly a relationship. Makes sense, since his ex shafted him out of that money. I'd say just play it cool and be honest about it. Just keep being yourself and he'll get the picture.