I was asked about how to run a suite of 65.000.000.000 tests and I wonder if it is normal to have a project with such a huge amount of tests.

Have you worked in projects with this characteristic?

With 65 billion tests, it sounds like you're being asked to test all possible inputs. This is not useful--you'd essentially be testing that your processor functions correctly, not that your code is correct.

You should be testing equivalence classes instead. This will drastically reduce your range of test inputs.

Also consider whether you can subdivide your system into smaller pieces. Each piece will be easier to test in isolation, and then you can perform some integration tests which bring all the pieces together.

If you still want that reassurance that some of those input combinations work, perhaps you could try fuzz testing. You will get some of the benefits of testing lots of different inputs, but without running all 65 billion of them.
