The intermediate and final build products from running tests are all stored in Isolate, and can be downloaded to the desktop for inspection and debugging.
First install the client:
git clone https://github.com/luci/client-py.git
Add the checkout location to your $PATH.
To download the isolated files for a test first visit the build status page and find the “isolated output” link:
Follow that link to find the hash of the isolated outputs:
isolateserver.py with --isolated set to that hash:
$ isolateserver.py \ download \ --isolate-server=https://isolateserver.appspot.com \ --isolated=5b85b7c382ee2a34530e33c7db20a07515ff9481 \ --target=./download/