exercism/exercism.io — pull request #1260 by ernesto-jimenez (2014-01-05 20:19:23+00:00)
Title: Should use %v for functions, not %s

```go vet``` complaints about the current implementation:
```accumulate_test.go:27: arg test.converter for printf verb %s of wrong type: func(string) string```

%#v is a best fit for this