Sample tryjob: https://ci.chromium.org/p/chromium/builders/luci.chromium.findit/findit_variable/1997

There were 20 shards for the swarming task, while only one of them ran the specified test for 20 times, left 19 other shards failed with 253 (No test to run) (ref: https://bugs.chromium.org/p/chromium/issues/detail?id=533481#c41). 

This failures make the test results to be marked as invalid so no pass_fail_counts was populated as well.

I'll first write a change to handle no pass_fail_count gracefully. 

But we also need to handle the return code 253 problem, otherwise there will be no result for the try jobs. 

 

Sample tryjob: https://ci.chromium.org/p/chromium/builders/luci.chromium.findit/findit_variable/1997

There were 20 shards for the swarming task, while only one of them ran the specified test for 20 times, left 19 other shards failed with 253 (No test to run) (saw https://bugs.chromium.org/p/chromium/issues/detail?id=533481#c41 to confirm return_code 253's meaning). 

This failures make the test results to be marked as invalid so no pass_fail_counts was populated as well.

I'll first write a change to handle no pass_fail_count gracefully. 

But we also need to handle the return code 253 problem, otherwise there will be no result for the try jobs.