> If I release an open source product, but then say you can only make modifications and sell it if you pass my tests (which I don't make freely available), it's not really open right?

I believe your restriction on making derived works conflicts with just about every free and open-source license out there. What Sun did and Oracle does prohibit you from doing is calling something that doesn't pass the non-freely-available TCK by the name Java or implying it's Java-compatible.

As for Dalvik, it's not derived from a project Oracle contributed the said patents. In this way, Dalvik is not protected agains Oracle's lawyers.

I think reversing a linked-list using recursion is a walk in the park compared to trying to understand patent/trademark law for software.

I believe the reason is that it was not derived from anything, such as OpenJDK, that had existing licensing protection.

You would not get a trademark lawsuit. Patents have different rules.