Extend test API about rascal HOT 6 OPEN

Possible workaround: use exceptions or assert instead of booleans to make the test fail

from rascal.

This is an excellent idea; and a duplicate of the ancient #1010

from rascal.

I think the compiler can just interpret the existing boolean operators differently. There is no need for an API like JUnit.assertEqual or something. If I write test f(int a, int b) = a + b == b + a it is already clear that I am asserting that both sides of the == are equal.

from rascal.

I think the compiler can just interpret the existing boolean operators differently.

Yes, for equality that works perfectly. But depending on how complex the tests get, we are still in trouble:

• what do we do when only partial matches are relevant, for example in a string?
• what do we do if a test requires more than one comparison? For example, testing a list usually requires to check its size and its elements. Checking for equality would again merge both cases into one

from rascal.

There are limits with what we can do, indeed. However if we bring it up too the level of junit asserts, (equals, unequals, booleans) with proper diffs, we are already much richer than what we have now (false).

Also input minimisation (random or brute force or heuristically) would help a lot.

from rascal.

The next step would be to bring in a theory of pattern matching and parsing; i.e if a match fails we could explain why or produce a smaller test case that also fails for the same reason.

from rascal.