Add unit test for part 1 of bug 659022

This tests a case where gtk_tree_model_filter_row_changed() is run
for a node with visible_siter != NULL, however its parent has
visible_iter == NULL. For this case, no valid paths can be generated
as the node cannot be accessed (because the parent is invisible).

gtk/tests/filtermodel.c

@@ -6602,6 +6602,65 @@ specific_bug_658696 (void)
   g_object_unref (filter);
 }
 
+static gboolean
+specific_bug_659022_visible_func (GtkTreeModel *model,
+                                  GtkTreeIter  *iter,
+                                  gpointer      data)
+{
+  GtkTreeIter tmp;
+
+  if (!gtk_tree_model_iter_parent (model, &tmp, iter))
+    {
+      if (gtk_tree_model_iter_n_children (model, iter) >= 2)
+        return TRUE;
+      else
+        return FALSE;
+    }
+
+  return TRUE;
+}
+
+static void
+specific_bug_659022_row_changed_emission (void)
+{
+  GtkTreeModel *filter;
+  GtkTreeModel *model;
+  GtkTreeModelRefCount *ref_model;
+  GtkTreeIter parent, child, child2;
+  GtkTreePath *path;
+  GtkWidget *tree_view;
+
+  model = gtk_tree_model_ref_count_new ();
+  ref_model = GTK_TREE_MODEL_REF_COUNT (model);
+
+  filter = gtk_tree_model_filter_new (model, NULL);
+  gtk_tree_model_filter_set_visible_func (GTK_TREE_MODEL_FILTER (filter),
+                                          specific_bug_659022_visible_func,
+                                          NULL, NULL);
+
+  tree_view = gtk_tree_view_new_with_model (GTK_TREE_MODEL (filter));
+
+  gtk_tree_store_insert (GTK_TREE_STORE (model), &parent, NULL, 0);
+  gtk_tree_store_insert (GTK_TREE_STORE (model), &child, &parent, 0);
+  gtk_tree_store_insert (GTK_TREE_STORE (model), &child2, &parent, 0);
+
+  gtk_tree_view_expand_all (GTK_TREE_VIEW (tree_view));
+
+  gtk_tree_model_filter_refilter (GTK_TREE_MODEL_FILTER (filter));
+
+  gtk_tree_store_remove (GTK_TREE_STORE (model), &child2);
+
+  gtk_tree_model_filter_refilter (GTK_TREE_MODEL_FILTER (filter));
+
+  path = gtk_tree_model_get_path (model, &child);
+  gtk_tree_model_row_changed (model, path, &child);
+  gtk_tree_path_free (path);
+
+  gtk_widget_destroy (tree_view);
+  g_object_unref (filter);
+  g_object_unref (model);
+}
+
 /* main */
 
 void
@@ -6955,4 +7014,6 @@ register_filter_model_tests (void)
                    specific_bug_657353);
   g_test_add_func ("/TreeModelFilter/specific/bug-658696",
                    specific_bug_658696);
+  g_test_add_func ("/TreeModelFilter/specific/bug-659022/row-changed-emission",
+                   specific_bug_659022_row_changed_emission);
 }