write tests

[Apanatshka]

Did you have anything specific in mind here?

[BurntSushi]

Unit tests:

• Test the benchmark parser, including the fact that throughput is optional.
• Test that find overlap finds the correct pairs.
• Test that find overlap reports correct missing benchmarks (for both old and new).
• Test that the name determination for the two columns works correctly when given two file paths. (This may require refactoring the names method off of the Args struct.)
• Test commafy.

Integration tests:

• Test some basic example inputs and check that it produces the expected output.
• Test that the name prefix feature works. (Possibly also refactor code into a unit test.)
• Test that passing input on stdin works.

There may be others but this is all I've got off the top of my head at the moment. Bonus points if we can use quickcheck.

[Apanatshka]

Given #10 and #13, can we close this?

[BurntSushi]

Oh yes indeed! Thanks so much. :-)