add leveldb collection destroy to tests

leveldb_test.go

@@ -69,6 +69,7 @@ func TestLevelDB(t *testing.T) {
 		named("iterSortKeys", tester.IterSortKeys),
 		named("deleteAll", tester.DeleteAll),
 		named("close", tester.Close),
+		named("destroy", collection.Destroy),
 	}
 	for _, do := range sequence {
 		do()