Retain previous test results and do an incremental update

[DougCompton]

I do not have devices for all of the configurations I need to test against, and need to use AVDs. I need spoon to retain the previous test results so I can rerun it using a different AVD.

The end result will be one spoon report, that shows the results of multiple runs against several AVDs.

[RichardGuion]

I had a slight variation on this request, was about to open an issue. I would like to keep a history of test runs, so I can go back and see if I ran the tests a week ago and what the status was. Ideally I would like to have an option to keep X test runs. There would be a master index.html pointing me to the last X runs, and if you clicked on one of the test runs, it would lead you to a page of the results (what index.html presents now).

[JakeWharton]

@RichardGuion See #1

[JakeWharton]

@DougCompton I could see use in a command-line flag that would allow you merge output results.

Something like:

spoon --output all-the-things/ --merge foo/ bar/ baz/

[DougCompton]

@JakeWharton That would meet my requirements.

Another option would be a command-line flag, --update, that would not delete the output directory, just the device specific directories for the attached devices. Load the previous device results from file, and just update it with the results from the attached devices. That way the report generation would not have many, if any, changes.

Both ways would achieve the same results.

[JakeWharton]

True. I'll think about it a bit more. I'm wary of how simply merging on top of the existing output would work when we add history support.