There was already one `createFacts` method, used by some classes.
That one creates observations for all patients for the 1st and 2nd concepts.
I didn't find that a good criteria for my REST API tests (for the bootstrap data), and didn't want to adapt the tests using the existing method, so i created a 2nd method that creates less facts and different values.
So both methods create facts (each with its own createria), but its not easy to name them.
The original one create 2 * patient.size() facts, and the 2nd creates facts from the 'diagonal' of concept with patient (1st concept with 1st patient, 2nd concept with 2ns patient, etc..) and received the expected # of facts.
Do you have any good names? 
I could also move the 2nd `createFacts` method to the `TestData` class, but that would pollute a bit the class. I wanted to keep `TestData` as clean as possible, without know anything about how each of the specific test classes prepare their default/bootstrap data