Add dnd-character

[BNAndras]

I don't see a way of having students actually use randomly generated numbers, but I feel like it'd be evident in a mentoring discussion if a student didn't do that.

The test generator had trouble with the last three tests so tomorrow, I'll file another issue with the specifics.

[BNAndras]

Related to #172

[BNAndras]

@kotp, should I bump the difficulty? It's at 3, but students will need to figure out how to generate random numbers. A difficulty of 4 would mark it as a medium difficulty exercise.

I'm also thinking we add a test where we create two characters and compare their total ability score across the six attributes. Then, students can't hardcode ability scores. The chance of a false positive with two totals being the same and randomly generated should be fairly low, but we can add a comment inline for students to rerun that test if needed. I'd hope you'd only need to rerun that once or twice to get it to pass.

[kotp]

@kotp, should I bump the difficulty? It's at 3, but students will need to figure out how to generate random numbers. A difficulty of 4 would mark it as a medium difficulty exercise.

I think making it medium would be good. We can leave it and get a feeling back via feedback, as well for the students that do the exercise.

I'm also thinking we add a test where we create two characters and compare their total ability score across the six attributes. Then, students can't hardcode ability scores. The chance of a false positive with two totals being the same and randomly generated should be fairly low, but we can add a comment inline for students to rerun that test if needed. I'd hope you'd only need to rerun that once or twice to get it to pass.

We may not need the student to run the tests more than once. If the chances of the same result are fairly low, then we run the tests that threshold, and expect that the numbers do not stay the same total. If they change even once in 4 generations for that test, then the test is probably confirming random. Also, we can use srand() to force the sequence and check in that way as well. We would know what we would expect from the next generation.

[BNAndras]

Ooh, I didn't realize Vim had srand and rand for a while now. That'll help clean up the example.vim file as well.

[BNAndras]

Updated the difficulty and the stub. I'll work on the test suite. The randomness is in the dice roll, not the public-facing ability and modifier functions so I'll need to figure something out or just say good enough.

[kotp]

Approving in case we leave the randomness checks out for now.

We might generate a few characters to ensure that the attributes change in an expected way, but this is probably something that could be driven from problem-specifications, instead.

[BNAndras]

Yeah, the Java track generates a reference D&D character and then up to 1000 more characters, checking each time if at least one of the character's ability scores differ from the reference character's. Therefore, it'll fail quickly if values are hardcoded. That doesn't seem like it'd take a lot of time to run.