Test Runner

[sunjay]

Much like the test runner in Rhino, we should have something that runs the example brain files.

We could structure it like this:

examples/
    brain/
        test1.brain
        test1.in
        test1.out

The .in file is optional and can be used to provide input to the test .brn file. The test runner would be in tests/example_runner.rs or something. It would run each test with its input (if available) and compare it to the output to always ensure that our examples work.

• Be able to test errors as well like syntax errors, etc.
• Make sure all .brn examples at least compile (add this as a test)