Improve minitest output for candy tests

Expected and actual output were swapped.

Previously the actual output would be listed as expected.

```
  1) Failure:
CandyTest#test_candy_type [test/candy_test.rb:9]:
Expected: nil
  Actual: "Skittles"
```

This patch restores expected behavior.

```
  1) Failure:
CandyTest#test_candy_type [test/candy_test.rb:9]:
Expected: "Skittles"
  Actual: nil
```