Refactor multiarg, split MGS/PLS.

service/datastore/pls_test.go

Index: service/datastore/pls_test.go
diff --git a/service/datastore/pls_test.go b/service/datastore/pls_test.go
index c997765ff5c96a58ff26f6f0fb8a1de304c6e348..50480f1be474143565f0efa0e7d079415ec66c59 100644
--- a/service/datastore/pls_test.go
+++ b/service/datastore/pls_test.go
@@ -1813,10 +1813,17 @@ func TestMeta(t *testing.T) {
 		})
 
 		Convey("attempting to get a PLS for a non *struct is an error", func() {
-			So(func() { GetPLS((*[]string)(nil)) }, ShouldPanicLike,
+			s := []string{}
+			So(func() { GetPLS(&s) }, ShouldPanicLike,
 				"cannot GetPLS(*[]string): not a pointer-to-struct")
 		})
 
+		Convey("attempting to get a PLS for a nil pointer-to-struct is an error", func() {
+			var s *Simple
+			So(func() { GetPLS(s) }, ShouldPanicLike,
+				"cannot GetPLS(*datastore.Simple): pointer is nil")
+		})
+
 		Convey("convertible meta default types", func() {
 			type OKDefaults struct {
 				When   string `gae:"$when,tomorrow"`