import "sys" used by py/file tests

Author: raff

pytest/pytest.go

@@ -12,6 +12,7 @@ import (
 	"testing"
 
 	_ "github.com/go-python/gpython/builtin"
+	_ "github.com/go-python/gpython/sys"
 	"github.com/go-python/gpython/compile"
 	"github.com/go-python/gpython/py"
 	"github.com/go-python/gpython/vm"