
When running $ go test ./tests/matrix/ in isolation, it failed like this: fd leak? before, after: [0r=/dev/null 3w=/dev/null 5r=/proc/8078/fd (hidden:4)] [0r=/dev/null 3w=/dev/null 5w=/tmp/go-build366655199/b001/testlog.txt 7r=/proc/8078/fd (hidden:4)] Filter by prefix to get rid of this spurious test failure.