headssummary: directly feed the function with the 'pushop' object Our goal is to be able to perform the post processing directly into the '_headssummary' function. However before this patch the '_headsummary' function only had access to repo, remote, outgoing while the '_postprocessobsolete' function takes a 'pushop' object. Experience shows that having the 'pushop' object helps extensions so we update '_headssummary' to take a pushop object as argument.

checkheads: gather the postprocessing with other obsolescence specific code We extract this function from the loop and gather it with the rest of the obsolescence specific code. That will help to clarify the move of the whole logic inside the "heads summary" computation.

run-tests: add a way to list tests, with JSON and XUnit support Some test runners are interested in listing tests, so they can do their own filtering on top (usually based on attributes like historically observed runtime). Add support for that.

run-tests: install hg after computing tests to run We're going to add a way to list tests, and we don't need to install hg for that.

run-tests: make time field optional for xunit report We're going to use XUnit to list tests, and we don't have a time field in that case.

run-tests: factor out json write code into another method We're going to use this code to output a JSON-formatted listing of tests.