From 37f53875a11df741cf5eddfe1a2825b57731e1cd Mon Sep 17 00:00:00 2001
From: peter <petrel.harp@gmail.com>
Date: Mon, 6 Nov 2023 10:53:46 -0800
Subject: [PATCH] one more c test

---
 c/tests/test_trees.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/c/tests/test_trees.c b/c/tests/test_trees.c
index 58226a0e5b..1302e639d1 100644
--- a/c/tests/test_trees.c
+++ b/c/tests/test_trees.c
@@ -8256,6 +8256,12 @@ test_extend_edges_errors(void)
     const char *migrations = "0  10  0  0  1  0.5\n"
                              "0  10  0  1  0  1.5\n";
 
+    tsk_treeseq_from_text(
+        &ts, 10, nodes, edges, NULL, sites, mutations, NULL, NULL, 0);
+    ret = tsk_treeseq_extend_edges(&ts, -2, 0, &ets);
+    CU_ASSERT_EQUAL_FATAL(ret, TSK_ERR_EXTEND_EDGES_BAD_MAXITER);
+    tsk_treeseq_free(&ts);
+
     tsk_treeseq_from_text(
         &ts, 10, nodes, edges, migrations, sites, mutations, NULL, NULL, 0);
     ret = tsk_treeseq_extend_edges(&ts, 10, 0, &ets);