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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// 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"
#include "ui/accessibility/ax_tree.h"
#include "ui/accessibility/ax_tree_serializer.h"
#include "ui/accessibility/tree_generator.h"
namespace ui {
namespace {
// A function to turn a tree into a string, capturing only the node ids
// and their relationship to one another.
//
// The string format is kind of like an S-expression, with each expression
// being either a node id, or a node id followed by a subexpression
// representing its children.
//
// Examples:
//
// (1) is a tree with a single node with id 1.
// (1 (2 3)) is a tree with 1 as the root, and 2 and 3 as its children.
// (1 (2 (3))) has 1 as the root, 2 as its child, and then 3 as the child of 2.
void TreeToStringHelper(const AXNode* node, std::string* out_result) {
*out_result += base::IntToString(node->id());
if (node->child_count() != 0) {
*out_result += " (";
for (int i = 0; i < node->child_count(); ++i) {
if (i != 0)
*out_result += " ";
TreeToStringHelper(node->ChildAtIndex(i), out_result);
}
*out_result += ")";
}
}
std::string TreeToString(const AXTree& tree) {
std::string result;
TreeToStringHelper(tree.GetRoot(), &result);
return "(" + result + ")";
}
} // anonymous namespace
// Test the TreeGenerator class by building all possible trees with
// 3 nodes and the ids [1...3].
TEST(AXGeneratedTreeTest, TestTreeGenerator) {
int tree_size = 3;
TreeGenerator generator(tree_size);
const char* EXPECTED_TREES[] = {
"(1 (2 3))",
"(2 (1 3))",
"(3 (1 2))",
"(1 (3 2))",
"(2 (3 1))",
"(3 (2 1))",
"(1 (2 (3)))",
"(2 (1 (3)))",
"(3 (1 (2)))",
"(1 (3 (2)))",
"(2 (3 (1)))",
"(3 (2 (1)))",
};
int n = generator.UniqueTreeCount();
ASSERT_EQ(static_cast<int>(arraysize(EXPECTED_TREES)), n);
for (int i = 0; i < n; i++) {
AXTree tree;
generator.BuildUniqueTree(i, &tree);
std::string str = TreeToString(tree);
EXPECT_EQ(EXPECTED_TREES[i], str);
}
}
// Test mutating every possible tree with <n> nodes to every other possible
// tree with <n> nodes, where <n> is 4 in release mode and 3 in debug mode
// (for speed). For each possible combination of trees, we also vary which
// node we serialize first.
//
// For every possible scenario, we check that the AXTreeUpdate is valid,
// that the destination tree can unserialize it and create a valid tree,
// and that after updating all nodes the resulting tree now matches the
// intended tree.
TEST(AXGeneratedTreeTest, SerializeGeneratedTrees) {
// Do a more exhaustive test in release mode. If you're modifying
// the algorithm you may want to try even larger tree sizes if you
// can afford the time.
#ifdef NDEBUG
int tree_size = 4;
#else
LOG(WARNING) << "Debug build, only testing trees with 3 nodes and not 4.";
int tree_size = 3;
#endif
TreeGenerator generator(tree_size);
int n = generator.UniqueTreeCount();
for (int i = 0; i < n; i++) {
// Build the first tree, tree0.
AXSerializableTree tree0;
generator.BuildUniqueTree(i, &tree0);
SCOPED_TRACE("tree0 is " + TreeToString(tree0));
for (int j = 0; j < n; j++) {
// Build the second tree, tree1.
AXSerializableTree tree1;
generator.BuildUniqueTree(j, &tree1);
SCOPED_TRACE("tree1 is " + TreeToString(tree0));
// Now iterate over which node to update first, |k|.
for (int k = 0; k < tree_size; k++) {
SCOPED_TRACE("i=" + base::IntToString(i) +
" j=" + base::IntToString(j) +
" k=" + base::IntToString(k));
// Start by serializing tree0 and unserializing it into a new
// empty tree |dst_tree|.
scoped_ptr<AXTreeSource<const AXNode*> > tree0_source(
tree0.CreateTreeSource());
AXTreeSerializer<const AXNode*> serializer(tree0_source.get());
AXTreeUpdate update0;
serializer.SerializeChanges(tree0.GetRoot(), &update0);
AXTree dst_tree;
ASSERT_TRUE(dst_tree.Unserialize(update0));
// At this point, |dst_tree| should now be identical to |tree0|.
EXPECT_EQ(TreeToString(tree0), TreeToString(dst_tree));
// Next, pretend that tree0 turned into tree1, and serialize
// a sequence of updates to |dst_tree| to match.
scoped_ptr<AXTreeSource<const AXNode*> > tree1_source(
tree1.CreateTreeSource());
serializer.ChangeTreeSourceForTesting(tree1_source.get());
for (int k_index = 0; k_index < tree_size; ++k_index) {
int id = 1 + (k + k_index) % tree_size;
AXTreeUpdate update;
serializer.SerializeChanges(tree1.GetFromId(id), &update);
ASSERT_TRUE(dst_tree.Unserialize(update));
}
// After the sequence of updates, |dst_tree| should now be
// identical to |tree1|.
EXPECT_EQ(TreeToString(tree1), TreeToString(dst_tree));
}
}
}
}
} // namespace ui
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