Ty work

Created a lot more tests for ReverseGraph. Made tests to check the directedness of a reverse graph with 1 node, 5 nodes, and 10000 nodes.
hmm.....do you have any tests to actually test if the graph is, well,  actually reversed? 

it seems like you would have to use a different graph to check that (maybe a custom graph? i haven't tried using that class yet). it is not an issue with this PR, but just something to keep in mind.