[test/buffer] Add more tests for nil buffer

test/test-buffer.c

@@ -711,11 +711,49 @@ test_buffer_utf16_conversion (void)
   hb_buffer_destroy (b);
 }
 
+static void
+test_empty (hb_buffer_t *b)
+{
+  g_assert_cmpint (hb_buffer_get_length (b), ==, 0);
+  g_assert (!hb_buffer_get_glyph_infos (b, NULL));
+  g_assert (!hb_buffer_get_glyph_positions (b, NULL));
+}
+
 static void
 test_buffer_empty (void)
 {
+  hb_buffer_t *b = hb_buffer_get_empty ();
+
   g_assert (hb_buffer_get_empty ());
+  g_assert (hb_buffer_get_empty () == b);
   g_assert (hb_buffer_get_empty () == hb_buffer_create (-1));
+
+  g_assert (!hb_buffer_allocation_successful (b));
+
+  test_empty (b);
+
+  hb_buffer_add_utf32 (b, utf32, G_N_ELEMENTS (utf32), 1, G_N_ELEMENTS (utf32) - 2);
+
+  test_empty (b);
+
+  hb_buffer_reverse (b);
+  hb_buffer_reverse_clusters (b);
+
+  g_assert (!hb_buffer_set_length (b, 10));
+
+  test_empty (b);
+
+  g_assert (hb_buffer_set_length (b, 0));
+
+  test_empty (b);
+
+  g_assert (!hb_buffer_allocation_successful (b));
+
+  hb_buffer_reset (b);
+
+  test_empty (b);
+
+  g_assert (!hb_buffer_allocation_successful (b));
 }
 
 int