Make tree serialization more robust and add more unit tests.

ui/accessibility/ax_tree_unittest.cc

Index: ui/accessibility/ax_tree_unittest.cc
diff --git a/ui/accessibility/ax_tree_unittest.cc b/ui/accessibility/ax_tree_unittest.cc
index 3f11899c8536c908997bf357a519edaef9307363..9e21280a0669a1fe2002bfd17ec71f005779b0c5 100644
--- a/ui/accessibility/ax_tree_unittest.cc
+++ b/ui/accessibility/ax_tree_unittest.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/memory/scoped_ptr.h"
+#include "base/strings/string_number_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/accessibility/ax_node.h"
 #include "ui/accessibility/ax_serializable_tree.h"
@@ -11,7 +12,7 @@
 
 namespace ui {
 
-TEST(AXTreeTest, TestSerialize) {
+TEST(AXTreeTest, SerializeSimpleAXTree) {
   AXNodeData root;
   root.id = 1;
   root.role = AX_ROLE_ROOT_WEB_AREA;
@@ -58,4 +59,108 @@ TEST(AXTreeTest, TestSerialize) {
   EXPECT_EQ(checkbox.role, checkbox_node->data().role);
 }
 
+TEST(AXTreeTest, DeleteUnknownSubtreeFails) {
+  AXNodeData root;
+  root.id = 1;
+  root.role = AX_ROLE_ROOT_WEB_AREA;
+
+  AXTreeUpdate initial_state;
+  initial_state.nodes.push_back(root);
+  AXTree tree(initial_state);
+
+  // This should fail because we're asking it to delete
+  // a subtree rooted at id=2, which doesn't exist.
+  AXTreeUpdate update;
+  update.node_id_to_clear = 2;
+  update.nodes.resize(1);
+  update.nodes[0].id = 1;
+  update.nodes[0].id = AX_ROLE_ROOT_WEB_AREA;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Bad node_id_to_clear: 2", tree.error());
+}
+
+TEST(AXTreeTest, LeaveOrphanedDeletedSubtreeFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(3);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  initial_state.nodes[0].child_ids.push_back(2);
+  initial_state.nodes[0].child_ids.push_back(3);
+  initial_state.nodes[1].id = 2;
+  initial_state.nodes[2].id = 3;
+  AXTree tree(initial_state);
+
+  // This should fail because we delete a subtree rooted at id=2
+  // but never update it.
+  AXTreeUpdate update;
+  update.node_id_to_clear = 2;
+  update.nodes.resize(1);
+  update.nodes[0].id = 3;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Nodes left pending by the update: 2", tree.error());
+}
+
+TEST(AXTreeTest, LeaveOrphanedNewChildFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(1);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  AXTree tree(initial_state);
+
+  // This should fail because we add a new child to the root node
+  // but never update it.
+  AXTreeUpdate update;
+  update.nodes.resize(1);
+  update.nodes[0].id = 1;
+  update.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  update.nodes[0].child_ids.push_back(2);
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Nodes left pending by the update: 2", tree.error());
+}
+
+TEST(AXTreeTest, DuplicateChildIdFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(1);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  AXTree tree(initial_state);
+
+  // This should fail because a child id appears twice.
+  AXTreeUpdate update;
+  update.nodes.resize(2);
+  update.nodes[0].id = 1;
+  update.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  update.nodes[0].child_ids.push_back(2);
+  update.nodes[0].child_ids.push_back(2);
+  update.nodes[1].id = 2;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Node 1 has duplicate child id 2", tree.error());
+}
+
+TEST(AXTreeTest, InvalidReparentingFails) {
+  AXTreeUpdate initial_state;
+  initial_state.nodes.resize(3);
+  initial_state.nodes[0].id = 1;
+  initial_state.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  initial_state.nodes[0].child_ids.push_back(2);
+  initial_state.nodes[1].id = 2;
+  initial_state.nodes[1].child_ids.push_back(3);
+  initial_state.nodes[2].id = 3;
+
+  AXTree tree(initial_state);
+
+  // This should fail because node 3 is reparented from node 2 to node 1
+  // without deleting node 1's subtree first.
+  AXTreeUpdate update;
+  update.nodes.resize(3);
+  update.nodes[0].id = 1;
+  update.nodes[0].role = AX_ROLE_ROOT_WEB_AREA;
+  update.nodes[0].child_ids.push_back(3);
+  update.nodes[0].child_ids.push_back(2);
+  update.nodes[1].id = 2;
+  update.nodes[2].id = 3;
+  EXPECT_FALSE(tree.Unserialize(update));
+  ASSERT_EQ("Node 3 reparented from 2 to 1", tree.error());
+}
+
 }  // namespace ui