The initial PR had a check for nil metrics but after some refactoring in the PR the test case that was suppose cover HPC was missing a scenario where the metric was not nil but didn't contain any metrics. This fixes that case and adds a testcase to cover it.
Signed-off-by: James Sturtevant <jstur@microsoft.com>
Using array to build sub-tests is to avoid random pick. The shuffle
thing should be handled by go-test framework. And we should capture
range var before runing sub-test.
Signed-off-by: Wei Fu <fuweid89@gmail.com>