What steps will reproduce the problem?

odessa(~/src) % mkdir issue
odessa(~/src) % cd issue
odessa(~/src/issue) % echo "package issue" > issue_test.go

What is the expected output? What do you see instead?

odessa(~/src/issue) % go test -cover
# testmain
/var/folders/7q/5n_khbqj5z716gk0zvtywgv80000gn/T/go-build881215944/issue/_test/_testmain.go:11:
imported and not used: "issue"
FAIL    issue [build failed]
odessa(~/src/issue) % 

Please use labels and text to provide additional information.

odessa(~/src/issue) % uname -a
Darwin odessa.local 12.4.0 Darwin Kernel Version 12.4.0: Wed May  1 17:57:12 PDT 2013;
root:xnu-2050.24.15~1/RELEASE_X86_64 x86_64
odessa(~/src/issue) % go version
go version devel +ae81458f37d7 Tue Jul 30 04:31:15 2013 +0200 darwin/amd64