If you don't use the
GOPATH environment variable and you don't put your project folder under
$GOPATH/src the compiler won't find it. As I see it goclipse lets you skip the
GOPATH entirely but in this case you have to put your code under the
src directory that you can see in the Project Explorer. See the related section of the goclipe documentation.
Although I think you make your life harder by using a full-fetched IDE for go development. Just use the command line tools. And it has the added benefit that you will actually understand what's going on (IDEs hide this from you).
So for building you can use
go build or
go install. The latter will copy the binary to your
$GOPATH/bin directory. For running test just call
go test or
go test path/to/package. There is a hidden gem in the
go tool: when you are working with multiple packages in the same directory you can use
go test ./... to test all of them at once. This also works with other go commands.