This function used to be a private part of process.go.
Since I needed that functionality however I think it's better to make it public
than for me to copy it into my own code.
As a side effect of this change, I also fixed a bug in the function where Stolen
was not part of the sum. Having the function close to the CPUTimesStat
declaration will make problems like this less likely to re-occur in the future.
Package common wasn't used for public functions. Place it in an
internal directory to prevent other packages from using.
Remove the distributed references to "HOST_PROC" and "HOST_SYS"
consts and combine into a common function. This also helps so that
if a env var is defined with a trailing slash all will continue to
work as expected.
Fixes#100
Add common.invoker interface to mock exec.Command. common.FakeInvoker returns
expected file if exists instead of invoke exec.Command.
Currenly, mocking is enabled only process.Pids(). I will expand to other funcs incrementally.