net/spdy/spdy_priority_tree_test.cc

// 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 "net/spdy/spdy_priority_tree.h"

#include "base/basictypes.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace net {

using ::testing::ElementsAre;
using ::testing::IsEmpty;
using ::testing::UnorderedElementsAre;

namespace test {

template <typename NodeId>
class SpdyPriorityTreePeer {
 public:
  explicit SpdyPriorityTreePeer(SpdyPriorityTree<NodeId>* tree) : tree_(tree) {}

  void PropagateNodeState(NodeId node_id) {
    auto node = tree_->FindNode(node_id);
    tree_->PropagateNodeState(node);
  }

  int TotalChildWeights(NodeId node_id) const {
    return tree_->FindNode(node_id)->total_child_weights;
  }

  int TotalWriteableChildWeights(NodeId node_id) const {
    return tree_->FindNode(node_id)->total_writeable_child_weights;
  }

  bool ValidateInvariants() const {
    return tree_->ValidateInvariantsForTests();
  }

 private:
  SpdyPriorityTree<NodeId>* tree_;
};

class SpdyPriorityTreeTest : public ::testing::Test {
 protected:
  typedef uint32 SpdyStreamId;
  typedef std::pair<SpdyStreamId, float> PriorityNode;
  typedef std::vector<PriorityNode> PriorityList;

  SpdyPriorityTreeTest() : peer(&tree) {}

  SpdyPriorityTree<SpdyStreamId> tree;
  SpdyPriorityTreePeer<SpdyStreamId> peer;
};

TEST_F(SpdyPriorityTreeTest, AddAndRemoveNodes) {
  EXPECT_EQ(1, tree.num_nodes());
  EXPECT_TRUE(tree.NodeExists(0));
  EXPECT_FALSE(tree.NodeExists(1));

  EXPECT_TRUE(tree.AddNode(1, 0, 100, false));
  EXPECT_EQ(2, tree.num_nodes());
  ASSERT_TRUE(tree.NodeExists(1));
  EXPECT_EQ(100, tree.GetWeight(1));
  EXPECT_FALSE(tree.NodeExists(5));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(1));

  EXPECT_TRUE(tree.AddNode(5, 0, 50, false));
  // Should not be able to add a node with an id that already exists.
  EXPECT_FALSE(tree.AddNode(5, 1, 50, false));
  EXPECT_EQ(3, tree.num_nodes());
  EXPECT_TRUE(tree.NodeExists(1));
  ASSERT_TRUE(tree.NodeExists(5));
  EXPECT_EQ(50, tree.GetWeight(5));
  EXPECT_FALSE(tree.NodeExists(13));

  EXPECT_TRUE(tree.AddNode(13, 5, 130, true));
  EXPECT_EQ(4, tree.num_nodes());
  EXPECT_TRUE(tree.NodeExists(1));
  EXPECT_TRUE(tree.NodeExists(5));
  ASSERT_TRUE(tree.NodeExists(13));
  EXPECT_EQ(130, tree.GetWeight(13));
  EXPECT_EQ(5u, tree.GetParent(13));

  EXPECT_TRUE(tree.RemoveNode(5));
  // Cannot remove a node that has already been removed.
  EXPECT_FALSE(tree.RemoveNode(5));
  EXPECT_EQ(3, tree.num_nodes());
  EXPECT_TRUE(tree.NodeExists(1));
  EXPECT_FALSE(tree.NodeExists(5));
  EXPECT_TRUE(tree.NodeExists(13));
  EXPECT_EQ(0u, tree.GetParent(13));

  // The parent node 19 doesn't exist, so this should fail:
  EXPECT_FALSE(tree.AddNode(7, 19, 70, false));
  // This should succeed, creating node 7:
  EXPECT_TRUE(tree.AddNode(7, 13, 70, false));
  // Now node 7 already exists, so this should fail:
  EXPECT_FALSE(tree.AddNode(7, 1, 70, false));
  // Try adding a second child to node 13:
  EXPECT_TRUE(tree.AddNode(17, 13, 170, false));

  // TODO(birenroy): Add a separate test that verifies weight invariants when
  // SetWeight is called.
  EXPECT_TRUE(tree.SetWeight(17, 150));
  EXPECT_EQ(150, tree.GetWeight(17));

  ASSERT_TRUE(peer.ValidateInvariants());
}

// Basic case of reparenting a subtree.
TEST_F(SpdyPriorityTreeTest, SetParentBasicNonExclusive) {
  /* Tree:
        0
       / \
      1   2
     / \
    3   4
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 0, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 1, 100, false);
  EXPECT_TRUE(tree.SetParent(1, 2, false));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(2));
  EXPECT_THAT(tree.GetChildren(1), UnorderedElementsAre(3, 4));
  EXPECT_THAT(tree.GetChildren(2), ElementsAre(1));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

// Basic case of reparenting a subtree.  Result here is the same as the
// non-exclusive case.
TEST_F(SpdyPriorityTreeTest, SetParentBasicExclusive) {
  /* Tree:
        0
       / \
      1   2
     / \
    3   4
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 0, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 1, 100, false);
  EXPECT_TRUE(tree.SetParent(1, 2, true));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(2));
  EXPECT_THAT(tree.GetChildren(1), UnorderedElementsAre(3, 4));
  EXPECT_THAT(tree.GetChildren(2), ElementsAre(1));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

// We can't set the parent of a nonexistent node, or set the parent to a
// nonexistent node.
TEST_F(SpdyPriorityTreeTest, SetParentNonexistent) {
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 0, 100, false);
  bool test_bool_values[] = {true, false};
  for (bool exclusive : test_bool_values) {
    EXPECT_FALSE(tree.SetParent(1, 3, exclusive));
    EXPECT_FALSE(tree.SetParent(4, 2, exclusive));
    EXPECT_FALSE(tree.SetParent(3, 4, exclusive));
    EXPECT_THAT(tree.GetChildren(0), UnorderedElementsAre(1, 2));
    EXPECT_THAT(tree.GetChildren(1), IsEmpty());
    EXPECT_THAT(tree.GetChildren(2), IsEmpty());
  }
  ASSERT_TRUE(peer.ValidateInvariants());
}

// We should be able to add multiple children to nodes.
TEST_F(SpdyPriorityTreeTest, SetParentMultipleChildrenNonExclusive) {
  /* Tree:
        0
       / \
      1   2
     / \   \
    3   4   5
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 0, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 1, 100, false);
  tree.AddNode(5, 2, 100, false);
  EXPECT_TRUE(tree.SetParent(2, 1, false));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(1));
  EXPECT_THAT(tree.GetChildren(1), UnorderedElementsAre(2, 3, 4));
  EXPECT_THAT(tree.GetChildren(2), ElementsAre(5));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), IsEmpty());
  EXPECT_THAT(tree.GetChildren(5), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, SetParentMultipleChildrenExclusive) {
  /* Tree:
        0
       / \
      1   2
     / \   \
    3   4   5
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 0, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 1, 100, false);
  tree.AddNode(5, 2, 100, false);
  EXPECT_TRUE(tree.SetParent(2, 1, true));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(1));
  EXPECT_THAT(tree.GetChildren(1), ElementsAre(2));
  EXPECT_THAT(tree.GetChildren(2), UnorderedElementsAre(3, 4, 5));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), IsEmpty());
  EXPECT_THAT(tree.GetChildren(5), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, SetParentToChildNonExclusive) {
  /* Tree:
        0
        |
        1
       / \
      2   3
      |
      4
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 1, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 2, 100, false);
  EXPECT_TRUE(tree.SetParent(1, 2, false));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(2));
  EXPECT_THAT(tree.GetChildren(1), ElementsAre(3));
  EXPECT_THAT(tree.GetChildren(2), UnorderedElementsAre(1, 4));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, SetParentToChildExclusive) {
  /* Tree:
        0
        |
        1
       / \
      2   3
      |
      4
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 1, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 2, 100, false);
  EXPECT_TRUE(tree.SetParent(1, 2, true));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(2));
  EXPECT_THAT(tree.GetChildren(1), UnorderedElementsAre(3, 4));
  EXPECT_THAT(tree.GetChildren(2), ElementsAre(1));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, SetParentToGrandchildNonExclusive) {
  /* Tree:
        0
        |
        1
       / \
      2   3
     / \
    4   5
    |
    6
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 1, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 2, 100, false);
  tree.AddNode(5, 2, 100, false);
  tree.AddNode(6, 4, 100, false);
  EXPECT_TRUE(tree.SetParent(1, 4, false));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(4));
  EXPECT_THAT(tree.GetChildren(1), UnorderedElementsAre(2, 3));
  EXPECT_THAT(tree.GetChildren(2), ElementsAre(5));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), UnorderedElementsAre(1, 6));
  EXPECT_THAT(tree.GetChildren(5), IsEmpty());
  EXPECT_THAT(tree.GetChildren(6), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, SetParentToGrandchildExclusive) {
  /* Tree:
        0
        |
        1
       / \
      2   3
     / \
    4   5
    |
    6
   */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 1, 100, false);
  tree.AddNode(3, 1, 100, false);
  tree.AddNode(4, 2, 100, false);
  tree.AddNode(5, 2, 100, false);
  tree.AddNode(6, 4, 100, false);
  EXPECT_TRUE(tree.SetParent(1, 4, true));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(4));
  EXPECT_THAT(tree.GetChildren(1), UnorderedElementsAre(2, 3, 6));
  EXPECT_THAT(tree.GetChildren(2), ElementsAre(5));
  EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  EXPECT_THAT(tree.GetChildren(4), ElementsAre(1));
  EXPECT_THAT(tree.GetChildren(5), IsEmpty());
  EXPECT_THAT(tree.GetChildren(6), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, SetParentToParent) {
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 1, 100, false);
  tree.AddNode(3, 1, 100, false);
  bool test_bool_values[] = {true, false};
  for (bool exclusive : test_bool_values) {
    EXPECT_TRUE(tree.SetParent(2, 1, exclusive));
    EXPECT_THAT(tree.GetChildren(0), ElementsAre(1));
    EXPECT_THAT(tree.GetChildren(1), UnorderedElementsAre(2, 3));
    EXPECT_THAT(tree.GetChildren(2), IsEmpty());
    EXPECT_THAT(tree.GetChildren(3), IsEmpty());
  }
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, SetParentToSelf) {
  tree.AddNode(1, 0, 100, false);
  EXPECT_FALSE(tree.SetParent(1, 1, false));
  EXPECT_FALSE(tree.SetParent(1, 1, true));
  EXPECT_THAT(tree.GetChildren(0), ElementsAre(1));
  EXPECT_THAT(tree.GetChildren(1), IsEmpty());
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, BlockAndUnblock) {
  /* Create the tree.

             0
           / | \
          /  |  \
         1   2   3
        / \   \   \
       4   5   6   7
      /|  / \  |   |\
     8 9 10 11 12 13 14
    / \
   15 16

  */
  tree.AddNode(1, 0, 100, false);
  tree.AddNode(2, 0, 100, false);
  tree.AddNode(3, 0, 100, false);
  tree.AddNode(4, 1, 100, false);
  tree.AddNode(5, 1, 100, false);
  tree.AddNode(8, 4, 100, false);
  tree.AddNode(9, 4, 100, false);
  tree.AddNode(10, 5, 100, false);
  tree.AddNode(11, 5, 100, false);
  tree.AddNode(15, 8, 100, false);
  tree.AddNode(16, 8, 100, false);
  tree.AddNode(12, 2, 100, false);
  tree.AddNode(6, 2, 100, true);
  tree.AddNode(7, 0, 100, false);
  tree.AddNode(13, 7, 100, true);
  tree.AddNode(14, 7, 100, false);
  tree.SetParent(7, 3, false);
  EXPECT_EQ(0u, tree.GetParent(1));
  EXPECT_EQ(0u, tree.GetParent(2));
  EXPECT_EQ(0u, tree.GetParent(3));
  EXPECT_EQ(1u, tree.GetParent(4));
  EXPECT_EQ(1u, tree.GetParent(5));
  EXPECT_EQ(2u, tree.GetParent(6));
  EXPECT_EQ(3u, tree.GetParent(7));
  EXPECT_EQ(4u, tree.GetParent(8));
  EXPECT_EQ(4u, tree.GetParent(9));
  EXPECT_EQ(5u, tree.GetParent(10));
  EXPECT_EQ(5u, tree.GetParent(11));
  EXPECT_EQ(6u, tree.GetParent(12));
  EXPECT_EQ(7u, tree.GetParent(13));
  EXPECT_EQ(7u, tree.GetParent(14));
  EXPECT_EQ(8u, tree.GetParent(15));
  EXPECT_EQ(8u, tree.GetParent(16));
  ASSERT_TRUE(peer.ValidateInvariants());

  EXPECT_EQ(peer.TotalChildWeights(0),
            tree.GetWeight(1) + tree.GetWeight(2) + tree.GetWeight(3));
  EXPECT_EQ(peer.TotalChildWeights(3), tree.GetWeight(7));
  EXPECT_EQ(peer.TotalChildWeights(7), tree.GetWeight(13) + tree.GetWeight(14));
  EXPECT_EQ(peer.TotalChildWeights(13), 0);
  EXPECT_EQ(peer.TotalChildWeights(14), 0);

  // Set all nodes ready to write.
  EXPECT_TRUE(tree.SetReady(1, true));
  EXPECT_TRUE(tree.SetReady(2, true));
  EXPECT_TRUE(tree.SetReady(3, true));
  EXPECT_TRUE(tree.SetReady(4, true));
  EXPECT_TRUE(tree.SetReady(5, true));
  EXPECT_TRUE(tree.SetReady(6, true));
  EXPECT_TRUE(tree.SetReady(7, true));
  EXPECT_TRUE(tree.SetReady(8, true));
  EXPECT_TRUE(tree.SetReady(9, true));
  EXPECT_TRUE(tree.SetReady(10, true));
  EXPECT_TRUE(tree.SetReady(11, true));
  EXPECT_TRUE(tree.SetReady(12, true));
  EXPECT_TRUE(tree.SetReady(13, true));
  EXPECT_TRUE(tree.SetReady(14, true));
  EXPECT_TRUE(tree.SetReady(15, true));
  EXPECT_TRUE(tree.SetReady(16, true));

  // Number of readable child weights should not change because
  // 7 has unblocked children.
  tree.SetBlocked(7, true);
  peer.PropagateNodeState(kRootNodeId);
  EXPECT_EQ(peer.TotalChildWeights(3), peer.TotalWriteableChildWeights(3));

  // Readable children for 7 should decrement.
  // Number of readable child weights for 3 still should not change.
  tree.SetBlocked(13, true);
  peer.PropagateNodeState(kRootNodeId);
  EXPECT_EQ(peer.TotalChildWeights(3), peer.TotalWriteableChildWeights(3));
  EXPECT_EQ(tree.GetWeight(14), peer.TotalWriteableChildWeights(7));

  // Once 14 becomes blocked, readable children for 7 and 3 should both be
  // decremented. Total readable weights at the root should still be the same
  // because 3 is still writeable.
  tree.SetBlocked(14, true);
  peer.PropagateNodeState(kRootNodeId);
  EXPECT_EQ(0, peer.TotalWriteableChildWeights(3));
  EXPECT_EQ(0, peer.TotalWriteableChildWeights(7));
  EXPECT_EQ(peer.TotalChildWeights(0),
            tree.GetWeight(1) + tree.GetWeight(2) + tree.GetWeight(3));

  // And now the root should be decremented as well.
  tree.SetBlocked(3, true);
  peer.PropagateNodeState(kRootNodeId);
  EXPECT_EQ(tree.GetWeight(1) + tree.GetWeight(2),
            peer.TotalWriteableChildWeights(0));

  // Unblocking 7 should propagate all the way up to the root.
  tree.SetBlocked(7, false);
  peer.PropagateNodeState(kRootNodeId);
  EXPECT_EQ(peer.TotalWriteableChildWeights(0),
            tree.GetWeight(1) + tree.GetWeight(2) + tree.GetWeight(3));
  EXPECT_EQ(peer.TotalWriteableChildWeights(3), tree.GetWeight(7));
  EXPECT_EQ(0, peer.TotalWriteableChildWeights(7));

  // Ditto for reblocking 7.
  tree.SetBlocked(7, true);
  peer.PropagateNodeState(kRootNodeId);
  EXPECT_EQ(peer.TotalWriteableChildWeights(0),
            tree.GetWeight(1) + tree.GetWeight(2));
  EXPECT_EQ(0, peer.TotalWriteableChildWeights(3));
  EXPECT_EQ(0, peer.TotalWriteableChildWeights(7));
  ASSERT_TRUE(peer.ValidateInvariants());
}

TEST_F(SpdyPriorityTreeTest, GetPriorityList) {
  PriorityList expected_list;
  PriorityList priority_list;

  /* Create the tree.

           0
          /|\
         1 2 3
        /| |\
       4 5 6 7
      /
     8

  */
  tree.AddNode(1, 0, 10, false);
  tree.AddNode(2, 0, 20, false);
  tree.AddNode(3, 0, 30, false);
  tree.AddNode(4, 1, 10, false);
  tree.AddNode(5, 1, 90, false);
  tree.AddNode(6, 2, 10, false);
  tree.AddNode(7, 2, 10, false);
  tree.AddNode(8, 4, 256, false);

  // Set all nodes ready to write.
  EXPECT_TRUE(tree.SetReady(1, true));
  EXPECT_TRUE(tree.SetReady(2, true));
  EXPECT_TRUE(tree.SetReady(3, true));
  EXPECT_TRUE(tree.SetReady(4, true));
  EXPECT_TRUE(tree.SetReady(5, true));
  EXPECT_TRUE(tree.SetReady(6, true));
  EXPECT_TRUE(tree.SetReady(7, true));
  EXPECT_TRUE(tree.SetReady(8, true));

  expected_list.push_back(PriorityNode(3, 1.0/2.0));
  expected_list.push_back(PriorityNode(2, 1.0/3.0));
  expected_list.push_back(PriorityNode(1, 1.0/6.0));
  priority_list = tree.GetPriorityList();
  EXPECT_EQ(expected_list, priority_list);

  // Check that the list updates as expected when a node gets blocked.
  EXPECT_TRUE(tree.SetReady(1, false));
  expected_list.clear();
  expected_list.push_back(PriorityNode(3, 1.0/2.0));
  expected_list.push_back(PriorityNode(2, 1.0/3.0));
  expected_list.push_back(PriorityNode(5, 0.9*1.0/6.0));
  expected_list.push_back(PriorityNode(4, 0.1*1.0/6.0));
  priority_list = tree.GetPriorityList();
  EXPECT_EQ(expected_list, priority_list);

  // Block multiple levels of nodes.
  EXPECT_TRUE(tree.SetReady(4, false));
  EXPECT_TRUE(tree.SetReady(5, false));
  expected_list.clear();
  expected_list.push_back(PriorityNode(3, 1.0/2.0));
  expected_list.push_back(PriorityNode(2, 1.0/3.0));
  expected_list.push_back(PriorityNode(8, 1.0/6.0));
  priority_list = tree.GetPriorityList();
  EXPECT_EQ(expected_list, priority_list);

  // Remove a node from the tree to make sure priorities
  // get redistributed accordingly.
  EXPECT_TRUE(tree.RemoveNode(1));
  expected_list.clear();
  expected_list.push_back(PriorityNode(3, 30.0/51.0));
  expected_list.push_back(PriorityNode(2, 20.0/51.0));
  expected_list.push_back(PriorityNode(8, 1.0/51.0));
  priority_list = tree.GetPriorityList();
  EXPECT_EQ(expected_list, priority_list);

  // Block an entire subtree.
  EXPECT_TRUE(tree.SetReady(8, false));
  expected_list.clear();
  expected_list.push_back(PriorityNode(3, 0.6));
  expected_list.push_back(PriorityNode(2, 0.4));
  priority_list = tree.GetPriorityList();
  EXPECT_EQ(expected_list, priority_list);

  // Unblock previously blocked nodes.
  EXPECT_TRUE(tree.SetReady(4, true));
  EXPECT_TRUE(tree.SetReady(5, true));
  expected_list.clear();
  expected_list.push_back(PriorityNode(3, 1.0/2.0));
  expected_list.push_back(PriorityNode(2, 1.0/3.0));
  expected_list.push_back(PriorityNode(5, 9.0/60.0));
  expected_list.push_back(PriorityNode(4, 1.0/60.0));
  priority_list = tree.GetPriorityList();
  EXPECT_EQ(expected_list, priority_list);

  // Blocked nodes in multiple subtrees.
  EXPECT_TRUE(tree.SetReady(2, false));
  EXPECT_TRUE(tree.SetReady(6, false));
  EXPECT_TRUE(tree.SetReady(7, false));
  expected_list.clear();
  expected_list.push_back(PriorityNode(3, 3.0/4.0));
  expected_list.push_back(PriorityNode(5, 9.0/40.0));
  expected_list.push_back(PriorityNode(4, 1.0/40.0));
  priority_list = tree.GetPriorityList();
  EXPECT_EQ(expected_list, priority_list);
}

TEST_F(SpdyPriorityTreeTest, CalculateRoundedWeights) {
  PriorityList expected_list;
  PriorityList priority_list;

  /* Create the tree.

           0
          / \
         1   2
       /| |\  |\
      8 3 4 5 6 7
  */
  tree.AddNode(3, 0, 100, false);
  tree.AddNode(4, 0, 100, false);
  tree.AddNode(5, 0, 100, false);
  tree.AddNode(1, 0, 10, true);
  tree.AddNode(2, 0, 5, false);
  tree.AddNode(6, 2, 1, false);
  tree.AddNode(7, 2, 1, false);
  tree.AddNode(8, 1, 1, false);

  // Remove higher-level nodes.
  tree.RemoveNode(1);
  tree.RemoveNode(2);

  // 3.3 rounded down = 3.
  EXPECT_EQ(3, tree.GetWeight(3));
  EXPECT_EQ(3, tree.GetWeight(4));
  EXPECT_EQ(3, tree.GetWeight(5));
  // 2.5 rounded up = 3.
  EXPECT_EQ(3, tree.GetWeight(6));
  EXPECT_EQ(3, tree.GetWeight(7));
  // 0 is not a valid weight, so round up to 1.
  EXPECT_EQ(1, tree.GetWeight(8));
}
}  // namespace test
}  // namespace gfe_spdy