I am working in an application that is mostly single-thread, single user. There are a few worker threads here and there, and they are only using thread safe objects and clas
There is the notion of an "Ordered Test" in which you can list tests in sequence. It is more geared towards ensuring a certain sequential order, but I can't see how that would be possible if B doesn't wait for A to complete.
Apart from that, it is unfortunate that your tests interfere with each other. There are Setup / TearDown methods that can be used per test such that it may after all be possible to isolate the tests from each other.