1 files changed, 7 insertions, 0 deletions
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index f54a461..79c16d7 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -176,6 +176,13 @@ TEST(unistd, ftruncate64) {
   ASSERT_EQ(123, sb.st_size);
 }
 
+TEST(unistd, ftruncate_negative) {
+  TemporaryFile tf;
+  errno = 0;
+  ASSERT_EQ(-1, ftruncate(tf.fd, -123));
+  ASSERT_EQ(EINVAL, errno);
+}
+
 static bool g_pause_test_flag = false;
 static void PauseTestSignalHandler(int) {
   g_pause_test_flag = true;