The organisation I work for has recently employed a testing officer to run manual tests, but when I asked about being given time as a developer to write unit tests the response was that the manual testing would provide a bigger bang for the buck. That is something that feels wrong to me and I'm looking for a means to rate manual and automated testing against each other that is more scientific than a gut-feeling. I'm not saying there is no place for manual testing - but automated testing would seem, to me at least, to remove some of the more repetitive and boring tasks. We have a build server that runs some unit tests and some selenium tests - so its not like the idea of automated testing is a no-go, but just seen as a lower return on investment.

I can understand that having someone perform a full end to end test of a system tests the final product and ultimately that's all the user cares about, but it is slow going and very repetitive. Manual regression testing means repeating all the previous tests and confirming nothing has changed and if there's 4 paths through a process then that's 4 manual tests that could well take 5 minutes each.  

So are there any verifiable facts and figures I can use to make the case for budgeting time for automated testing? For that matter what are [the disadvantages to automated testing][1] beyond those in the link?


  [1]: https://softwareengineering.stackexchange.com/a/116535/50392