I pushed an updated microbenchmark to CRAN a couple weeks ago. There were two noteworthy changes, thanks to great contributions from @MichaelChirico and @harvey131.
Michael fixed a bug in the check for whether the unit argument was a character string (#9, #10). The prior behavior was an uninformative error.
Harvey added a feature to allow you to use a string for common checks: “equal”, “identical”, and “equivalent” (#16). So you don’t need to create a custom function to use all.equal(), all.equal(…, check.attributes = FALSE), and identical, respectively.
I also converted the unit tests to use RUnit. I also made some changes to the repo, including adding a contributing guide and issue/pull-request templates.