prometheus/prometheus — pull request #340 by juliusv (2013-07-25 10:20:42+00:00)
Title: Send [] instead of "null" for empty result vectors, fix retrieval tests

There is still one broken operation_test.go test case, but I haven't figured out yet what the problem is. There's a comparison failing in the test, but when I print the two compared elements, they are exactly the same. We need to fix that later.