Add test for delete

filestore_memory.go

@@ -65,7 +65,7 @@ func (s *MemoryFileStore) Get(id string) (*File, error) {
 
 func (s *MemoryFileStore) Delete(id string) error {
 	s.lock.Lock()
-	defer s.lock.RUnlock()
+	defer s.lock.Unlock()
 	delete(s.data, id)
 	return nil
 }

filestore_test.go

@@ -59,5 +59,18 @@ func RunFilestoreTest(s gpaste.FileStore, t *testing.T) {
 		if ids[0] != id {
 			t.Fatalf("ID is wrong. Got %s want %s", ids[0], id)
 		}
+
+		// Delete
+		if err := s.Delete(id); err != nil {
+			t.Fatalf("Error deleting file: %s", err)
+		}
+
+		ids, err = s.List()
+		if err != nil {
+			t.Fatalf("Error listing after delete: %s", err)
+		}
+		if len(ids) != 0 {
+			t.Fatalf("List after delete has wrong length: %d", len(ids))
+		}
 	})
 }