:(

lol

I find the usage of Test.expect(actual == expected, "should be expected"); less optimal in comparison with Test.assertEquals(actual, expected); regarding test assertion output.

This would be especially helpful in "Submit tests", where we can't see your input.

The only information those failing tests give me is that it "should be something" but not what it actually was. :(

So, I was under the assumption that you'd also have to pass in the leaderboard array to that Leaderboard component.
My bad?

In the submit tests, what are you passing to the Leaderboard component?
this.props.leaderboard is undefined during that execution, whereas during the test phase there is a variable leaderboard containing 100 users.