kea/src/lib/datasrc/tests/rbtree_unittest.cc

// Copyright (C) 2010  Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.

#include <gtest/gtest.h>

#include <exceptions/exceptions.h>

#include <dns/name.h>
#include <dns/rrclass.h>
#include <dns/rrset.h>
#include <dns/rrtype.h>
#include <dns/rrttl.h>

#include <datasrc/rbtree.h>

#include <dns/tests/unittest_util.h>

using namespace std;
using namespace isc;
using namespace isc::dns;
using isc::UnitTestUtil;
using namespace isc::datasrc;

// XXX: some compilers cannot find class static constants used in
// EXPECT_xxx macros, for which we need an explicit empty definition.
const size_t Name::MAX_LABELS;

/* The initial structure of rbtree
 *
 *             b
 *           /   \
 *          a    d.e.f
 *              /  |   \
 *             c   |    g.h
 *                 |     |
 *                w.y    i
 *              /  |  \   \
 *             x   |   z   k
 *                 |   |
 *                 p   j
 *               /   \
 *              o     q
 */

namespace {
class RBTreeTest : public::testing::Test {
protected:
    RBTreeTest() : rbtree_expose_empty_node(true), crbtnode(NULL) {
        const char* const domain_names[] = {
            "c", "b", "a", "x.d.e.f", "z.d.e.f", "g.h", "i.g.h", "o.w.y.d.e.f",
            "j.z.d.e.f", "p.w.y.d.e.f", "q.w.y.d.e.f", "k.g.h"};
        int name_count = sizeof(domain_names) / sizeof(domain_names[0]);
        for (int i = 0; i < name_count; ++i) {
            rbtree.insert(Name(domain_names[i]), &rbtnode);
            rbtnode->setData(RBNode<int>::NodeDataPtr(new int(i + 1)));

            rbtree_expose_empty_node.insert(Name(domain_names[i]), &rbtnode);
            rbtnode->setData(RBNode<int>::NodeDataPtr(new int(i + 1)));

        }
    }

    RBTree<int> rbtree;
    RBTree<int> rbtree_expose_empty_node;
    RBNode<int>* rbtnode;
    const RBNode<int>* crbtnode;
};

TEST_F(RBTreeTest, getNodeCount) {
    EXPECT_EQ(14, rbtree.getNodeCount());
}

TEST_F(RBTreeTest, setGetData) {
    rbtnode->setData(RBNode<int>::NodeDataPtr(new int(11)));
    EXPECT_EQ(11, *(rbtnode->getData()));
}

TEST_F(RBTreeTest, insertNames) {
    EXPECT_EQ(RBTree<int>::ALREADYEXISTS, rbtree.insert(Name("d.e.f"),
                                                        &rbtnode));
    EXPECT_EQ(Name("d.e.f"), rbtnode->getName());
    EXPECT_EQ(14, rbtree.getNodeCount());

    //insert not exist node
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("."), &rbtnode));
    EXPECT_EQ(Name("."), rbtnode->getName());
    EXPECT_EQ(15, rbtree.getNodeCount());

    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("example.com"), &rbtnode));
    EXPECT_EQ(16, rbtree.getNodeCount());
    rbtnode->setData(RBNode<int>::NodeDataPtr(new int(12)));

    // return ALREADYEXISTS, since node "example.com" already has been explicitly inserted
    EXPECT_EQ(RBTree<int>::ALREADYEXISTS, rbtree.insert(Name("example.com"), &rbtnode));
    EXPECT_EQ(16, rbtree.getNodeCount());

    // split the node "d.e.f"
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("k.e.f"), &rbtnode));
    EXPECT_EQ(Name("k"), rbtnode->getName());
    EXPECT_EQ(18, rbtree.getNodeCount());

    // split the node "g.h"
    EXPECT_EQ(RBTree<int>::ALREADYEXISTS, rbtree.insert(Name("h"), &rbtnode));
    EXPECT_EQ(Name("h"), rbtnode->getName());
    EXPECT_EQ(19, rbtree.getNodeCount());

    // add child domain
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("m.p.w.y.d.e.f"), &rbtnode));
    EXPECT_EQ(Name("m"), rbtnode->getName());
    EXPECT_EQ(20, rbtree.getNodeCount());
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("n.p.w.y.d.e.f"), &rbtnode));
    EXPECT_EQ(Name("n"), rbtnode->getName());
    EXPECT_EQ(21, rbtree.getNodeCount());

    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("l.a"), &rbtnode));
    EXPECT_EQ(Name("l"), rbtnode->getName());
    EXPECT_EQ(22, rbtree.getNodeCount());

    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("r.d.e.f"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("s.d.e.f"), &rbtnode));
    EXPECT_EQ(24, rbtree.getNodeCount());

    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("h.w.y.d.e.f"), &rbtnode));

    // add more nodes one by one to cover leftRotate and rightRotate
    EXPECT_EQ(RBTree<int>::ALREADYEXISTS, rbtree.insert(Name("f"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("m"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("nm"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("om"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("k"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("l"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("fe"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("ge"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("i"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("ae"), &rbtnode));
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("n"), &rbtnode));
}

TEST_F(RBTreeTest, findName) {
    // find const rbtnode
    // exact match
    EXPECT_EQ(RBTree<int>::EXACTMATCH, rbtree.find(Name("a"), &crbtnode));
    EXPECT_EQ(Name("a"), crbtnode->getName());

    // not found
    EXPECT_EQ(RBTree<int>::NOTFOUND, rbtree.find(Name("d.e.f"), &crbtnode));
    EXPECT_EQ(RBTree<int>::NOTFOUND, rbtree.find(Name("y.d.e.f"), &crbtnode));
    EXPECT_EQ(RBTree<int>::NOTFOUND, rbtree.find(Name("x"), &crbtnode));
    EXPECT_EQ(RBTree<int>::NOTFOUND, rbtree.find(Name("m.n"), &crbtnode));

    // if we expose empty node, we can get the empty node created during insert
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              rbtree_expose_empty_node.find(Name("d.e.f"), &crbtnode));
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              rbtree_expose_empty_node.find(Name("w.y.d.e.f"), &crbtnode));

    // partial match
    EXPECT_EQ(RBTree<int>::PARTIALMATCH, rbtree.find(Name("m.b"), &crbtnode));
    EXPECT_EQ(Name("b"), crbtnode->getName());
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              rbtree_expose_empty_node.find(Name("m.d.e.f"), &crbtnode));

    // find rbtnode
    EXPECT_EQ(RBTree<int>::EXACTMATCH, rbtree.find(Name("q.w.y.d.e.f"), &rbtnode));
    EXPECT_EQ(Name("q"), rbtnode->getName());
}

TEST_F(RBTreeTest, findError) {
    // For the version that takes a node chain, the chain must be empty.
    RBTreeNodeChain<int> chain;
    EXPECT_EQ(RBTree<int>::EXACTMATCH, rbtree.find(Name("a"), &crbtnode,
                                                   chain));
    // trying to reuse the same chain.  it should result in an exception.
    EXPECT_THROW(rbtree.find(Name("a"), &crbtnode, chain),
                 BadValue);
}

TEST_F(RBTreeTest, flags) {
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("flags.example"),
                                                  &rbtnode));

    // by default, flags are all off
    EXPECT_FALSE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));

    // set operation, by default it enables the flag
    rbtnode->setFlag(RBNode<int>::FLAG_CALLBACK);
    EXPECT_TRUE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));

    // try disable the flag explicitly
    rbtnode->setFlag(RBNode<int>::FLAG_CALLBACK, false);
    EXPECT_FALSE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));

    // try enable the flag explicitly
    rbtnode->setFlag(RBNode<int>::FLAG_CALLBACK, true);
    EXPECT_TRUE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));

    // setting an unknown flag will trigger an exception
    EXPECT_THROW(rbtnode->setFlag(static_cast<RBNode<int>::Flags>(2), true),
                 isc::InvalidParameter);
}

bool
testCallback(const RBNode<int>&, bool* callack_checker) {
    *callack_checker = true;
    return (false);
}

TEST_F(RBTreeTest, callback) {
    // by default callback isn't enabled
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("callback.example"),
                                                  &rbtnode));
    rbtnode->setData(RBNode<int>::NodeDataPtr(new int(1)));
    EXPECT_FALSE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));

    // enable/re-disable callback
    rbtnode->setFlag(RBNode<int>::FLAG_CALLBACK);
    EXPECT_TRUE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));
    rbtnode->setFlag(RBNode<int>::FLAG_CALLBACK, false);
    EXPECT_FALSE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));

    // enable again for subsequent tests
    rbtnode->setFlag(RBNode<int>::FLAG_CALLBACK);
    // add more levels below and above the callback node for partial match.
    RBNode<int>* subrbtnode;
    EXPECT_EQ(RBTree<int>::SUCCESS, rbtree.insert(Name("sub.callback.example"),
                                                  &subrbtnode));
    subrbtnode->setData(RBNode<int>::NodeDataPtr(new int(2)));
    RBNode<int>* parentrbtnode;
    EXPECT_EQ(RBTree<int>::ALREADYEXISTS, rbtree.insert(Name("example"),
                                                       &parentrbtnode));
    //  the chilld/parent nodes shouldn't "inherit" the callback flag.
    // "rbtnode" may be invalid due to the insertion, so we need to re-find
    // it.
    EXPECT_EQ(RBTree<int>::EXACTMATCH, rbtree.find(Name("callback.example"),
                                                   &rbtnode));
    EXPECT_TRUE(rbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));
    EXPECT_FALSE(subrbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));
    EXPECT_FALSE(parentrbtnode->getFlag(RBNode<int>::FLAG_CALLBACK));

    // check if the callback is called from find()
    RBTreeNodeChain<int> node_path1;
    bool callback_called = false;
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              rbtree.find(Name("sub.callback.example"), &crbtnode, node_path1,
                          testCallback, &callback_called));
    EXPECT_TRUE(callback_called);

    // enable callback at the parent node, but it doesn't have data so
    // the callback shouldn't be called.
    RBTreeNodeChain<int> node_path2;
    parentrbtnode->setFlag(RBNode<int>::FLAG_CALLBACK);
    callback_called = false;
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              rbtree.find(Name("callback.example"), &crbtnode, node_path2,
                          testCallback, &callback_called));
    EXPECT_FALSE(callback_called);
}

TEST_F(RBTreeTest, chainLevel) {
    RBTreeNodeChain<int> chain;

    // by default there should be no level in the chain.
    EXPECT_EQ(0, chain.getLevelCount());

    // insert one node to the tree and find it.  there should be exactly
    // one level in the chain.
    RBTree<int> tree(true);
    Name node_name(Name::ROOT_NAME());
    EXPECT_EQ(RBTree<int>::SUCCESS, tree.insert(node_name, &rbtnode));
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              tree.find(node_name, &crbtnode, chain));
    EXPECT_EQ(1, chain.getLevelCount());

    /*
     * Now creating a possibly deepest tree with MAX_LABELS levels.
     * it should look like:
     *           (.)
     *            |
     *            a
     *            |
     *            a
     *            : (MAX_LABELS - 1) "a"'s
     *
     * then confirm that find() for the deepest name succeeds without any
     * disruption, and the resulting chain has the expected level.
     * Note that the root name (".") solely belongs to a single level,
     * so the levels begin with 2.
     */
    for (unsigned int i = 2; i <= Name::MAX_LABELS; ++i) {
        node_name = Name("a.").concatenate(node_name);
        EXPECT_EQ(RBTree<int>::SUCCESS, tree.insert(node_name, &rbtnode));
        RBTreeNodeChain<int> found_chain;
        EXPECT_EQ(RBTree<int>::EXACTMATCH,
                  tree.find(node_name, &crbtnode, found_chain));
        EXPECT_EQ(i, found_chain.getLevelCount());
    }

    // Confirm the last inserted name has the possible maximum length with
    // maximum label count.  This confirms the rbtree and chain level cannot
    // be larger.
    EXPECT_EQ(Name::MAX_LABELS, node_name.getLabelCount());
    EXPECT_THROW(node_name.concatenate(Name("a.")), TooLongName);
}

TEST_F(RBTreeTest, getAbsoluteNameError) {
    // an empty chain isn't allowed.
    RBTreeNodeChain<int> chain;
    EXPECT_THROW(chain.getAbsoluteName(), BadValue);
}

/*
 *the domain order should be:
 * a, b, c, d.e.f, x.d.e.f, w.y.d.e.f, o.w.y.d.e.f, p.w.y.d.e.f, q.w.y.d.e.f,
 * z.d.e.f, j.z.d.e.f, g.h, i.g.h, k.g.h
 *             b
 *           /   \
 *          a    d.e.f
 *              /  |   \
 *             c   |    g.h
 *                 |     |
 *                w.y    i
 *              /  |  \   \
 *             x   |   z   k
 *                 |   |
 *                 p   j
 *               /   \
 *              o     q
 */
const char* const names[] = {
    "a", "b", "c", "d.e.f", "x.d.e.f", "w.y.d.e.f", "o.w.y.d.e.f",
    "p.w.y.d.e.f", "q.w.y.d.e.f", "z.d.e.f", "j.z.d.e.f",
    "g.h", "i.g.h", "k.g.h"};
const size_t name_count(sizeof(names) / sizeof(*names));

TEST_F(RBTreeTest, nextNode) {
    RBTreeNodeChain<int> node_path;
    const RBNode<int>* node = NULL;
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              rbtree.find(Name(names[0]), &node, node_path));
    for (int i = 0; i < name_count; ++i) {
        EXPECT_NE(static_cast<void*>(NULL), node);
        EXPECT_EQ(Name(names[i]), node_path.getAbsoluteName());
        node = rbtree.nextNode(node_path);
    }

    // We should have reached the end of the tree.
    EXPECT_EQ(static_cast<void*>(NULL), node);
}

// Just walk using previousNode until the beginning of the tree and check it is
// OK
//
// rbtree - the tree to walk
// node - result of previous call to find(), starting position of the walk
// node_path - the path from the previous call to find(), will be modified
// chain_length - the number of names that should be in the chain to be walked
//   (0 means it should be empty, 3 means 'a', 'b' and 'c' should be there -
//   this is always from the beginning of the names[] list).
// skip_first - if this is false, the node should already contain the node with
//   the first name of the chain. If it is true, the node should be NULL
//   (true is for finds that return no match, false for the ones that return
//   match)
void
previousWalk(RBTree<int>& rbtree, const RBNode<int>* node,
             RBTreeNodeChain<int>& node_path, size_t chain_length,
             bool skip_first)
{
    if (skip_first) {
        // If the first is not found, this is supposed to be NULL and we skip
        // it in our checks.
        EXPECT_EQ(static_cast<void*>(NULL), node);
        node = rbtree.previousNode(node_path);
    }
    for (size_t i(chain_length); i > 0; --i) {
        EXPECT_NE(static_cast<void*>(NULL), node);
        EXPECT_EQ(Name(names[i - 1]), node_path.getAbsoluteName());
        // Find the node at the path and check the value is the same
        // (that it really returns the correct corresponding node)
        //
        // The "empty" nodes can not be found
        if (node->getData()) {
            const RBNode<int>* node2(NULL);
            RBTreeNodeChain<int> node_path2;
            EXPECT_EQ(RBTree<int>::EXACTMATCH,
                      rbtree.find(Name(names[i - 1]), &node2, node_path2));
            EXPECT_EQ(node, node2);
        }
        node = rbtree.previousNode(node_path);
    }

    // We should have reached the start of the tree.
    EXPECT_EQ(static_cast<void*>(NULL), node);

    // Calling previousNode() yet again should still return NULL without
    // fail.
    node = rbtree.previousNode(node_path);
    EXPECT_EQ(static_cast<void*>(NULL), node);
}

// Check the previousNode
TEST_F(RBTreeTest, previousNode) {
    // First, iterate the whole tree from the end to the beginning.
    RBTreeNodeChain<int> node_path;
    EXPECT_THROW(rbtree.previousNode(node_path), isc::BadValue) <<
        "Throw before a search was done on the path";
    const RBNode<int>* node(NULL);
    {
        SCOPED_TRACE("Iterate through");
        EXPECT_EQ(RBTree<int>::EXACTMATCH,
                  rbtree.find(Name(names[name_count - 1]), &node, node_path));
        previousWalk(rbtree, node, node_path, name_count, false);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Iterate from the middle");
        // Now, start somewhere in the middle, but within the real node.
        EXPECT_EQ(RBTree<int>::EXACTMATCH,
                  rbtree.find(Name(names[4]), &node, node_path));
        previousWalk(rbtree, node, node_path, 5, false);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start at the first");
        // If we start at the lowest (which is "a"), we get to the beginning
        // right away.
        EXPECT_EQ(RBTree<int>::EXACTMATCH,
                  rbtree.find(Name(names[0]), &node, node_path));
        EXPECT_NE(static_cast<void*>(NULL), node);
        EXPECT_EQ(static_cast<void*>(NULL), rbtree.previousNode(node_path));
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start before the first");
        // If we start before the lowest (0 < a), we should not get a node nor
        EXPECT_EQ(RBTree<int>::NOTFOUND,
                  rbtree.find<void*>(Name("0"), &node, node_path, NULL, NULL));
        EXPECT_EQ(static_cast<void*>(NULL), node);
        EXPECT_EQ(static_cast<void*>(NULL), rbtree.previousNode(node_path));
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start after the last");
        EXPECT_EQ(RBTree<int>::NOTFOUND,
                  rbtree.find(Name("z"), &node, node_path));
        previousWalk(rbtree, node, node_path, name_count, true);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start below a leaf");
        // We exit a leaf by going down. We should start by the one
        // we exited - 'c' (actually, we should get it by the find, as partial
        // match).
        EXPECT_EQ(RBTree<int>::PARTIALMATCH,
                  rbtree.find(Name("b.c"), &node, node_path));
        previousWalk(rbtree, node, node_path, 3, false);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start to the right of a leaf");
        // When searching for this, we exit the 'x' node to the right side,
        // so we should go x afterwards.

        // The d.e.f is empty node, so it is hidden by find. Therefore NOTFOUND
        // and not PARTIALMATCH.
        EXPECT_EQ(RBTree<int>::NOTFOUND,
                  rbtree.find(Name("xy.d.e.f"), &node, node_path));
        previousWalk(rbtree, node, node_path, 5, true);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start to the left of a leaf");
        // This is similar to the previous, but we exit the 'z' leaf to the
        // left side, so should not visit z at all then.

        // The d.e.f is empty node, so it is hidden by find. Therefore NOTFOUND
        // and not PARTIALMATCH.
        EXPECT_EQ(RBTree<int>::NOTFOUND,
                  rbtree.find(Name("yz.d.e.f"), &node, node_path));
        previousWalk(rbtree, node, node_path, 9, true);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start to the right of a parent");
        // When searching for this, we exit the 'g.h' node to the right
        // side, so we should go to g.h's children afterwards.

        // 'g.h' is an empty node, so we get a NOTFOUND and not
        // PARTIALMATCH.
        EXPECT_EQ(RBTree<int>::NOTFOUND,
                  rbtree.find(Name("x.h"), &node, node_path));
        // 'g.h' is the COMMONANCESTOR.
        EXPECT_EQ(node_path.getLastComparedNode()->getName(), Name("g.h"));
        EXPECT_EQ(NameComparisonResult::COMMONANCESTOR,
                  node_path.getLastComparisonResult().getRelation());
        // find() exits to the right of 'g.h'
        EXPECT_GT(node_path.getLastComparisonResult().getOrder(), 0);
        // We then descend into 'i.g.h' and walk all the nodes in the
        // tree.
        previousWalk(rbtree, node, node_path, name_count, true);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Start inside a wrong node");
        // The d.e.f is a single node, but we want only part of it. We
        // should start iterating before it.
        EXPECT_EQ(RBTree<int>::NOTFOUND,
                  rbtree.find(Name("e.f"), &node, node_path));
        previousWalk(rbtree, node, node_path, 3, true);
        node = NULL;
        node_path.clear();
    }

    {
        SCOPED_TRACE("Lookup in empty tree");
        // Just check it doesn't crash, etc.
        RBTree<int> empty_tree;
        EXPECT_EQ(RBTree<int>::NOTFOUND,
                  empty_tree.find(Name("x"), &node, node_path));
        EXPECT_EQ(static_cast<void*>(NULL), node);
        EXPECT_EQ(static_cast<void*>(NULL),
                  empty_tree.previousNode(node_path));
        node = NULL;
        node_path.clear();
    }
}

TEST_F(RBTreeTest, nextNodeError) {
    // Empty chain for nextNode() is invalid.
    RBTreeNodeChain<int> chain;
    EXPECT_THROW(rbtree.nextNode(chain), BadValue);
}

// A helper function for getLastComparedNode() below.
void
comparisonChecks(const RBTreeNodeChain<int>& chain,
                 int expected_order, int expected_common_labels,
                 NameComparisonResult::NameRelation expected_reln)
{
    if (expected_order > 0) {
        EXPECT_LT(0, chain.getLastComparisonResult().getOrder());
    } else if (expected_order < 0) {
        EXPECT_GT(0, chain.getLastComparisonResult().getOrder());
    } else {
        EXPECT_EQ(0, chain.getLastComparisonResult().getOrder());
    }
    EXPECT_EQ(expected_common_labels,
              chain.getLastComparisonResult().getCommonLabels());
    EXPECT_EQ(expected_reln,
              chain.getLastComparisonResult().getRelation());
}

TEST_F(RBTreeTest, getLastComparedNode) {
    RBTree<int>& tree = rbtree_expose_empty_node; // use the "empty OK" mode
    RBTreeNodeChain<int> chain;

    // initially there should be no 'last compared'.
    EXPECT_EQ(static_cast<void*>(NULL), chain.getLastComparedNode());

    // A search for an empty tree should result in no 'last compared', too.
    RBTree<int> empty_tree;
    EXPECT_EQ(RBTree<int>::NOTFOUND,
              empty_tree.find(Name("a"), &crbtnode, chain));
    EXPECT_EQ(static_cast<void*>(NULL), chain.getLastComparedNode());
    chain.clear();

    const RBNode<int>* expected_node = NULL;

    // Exact match case.  The returned node should be last compared.
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              tree.find(Name("x.d.e.f"), &expected_node, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // 2 = # labels of "x."
    comparisonChecks(chain, 0, 2, NameComparisonResult::EQUAL);
    chain.clear();

    // Partial match, search stopped at the matching node, which should be
    // the last compared node.
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              tree.find(Name("k.g.h"), &expected_node));
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              tree.find(Name("x.k.g.h"), &crbtnode, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // k.g.h < x.k.g.h, 2 = # labels of "k."
    comparisonChecks(chain, 1, 2, NameComparisonResult::SUBDOMAIN);
    chain.clear();

    // Partial match, search stopped in the subtree below the matching node
    // after following a left branch.
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              tree.find(Name("x.d.e.f"), &expected_node));
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              tree.find(Name("a.d.e.f"), &crbtnode, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // a < x, 1 = # labels of "." (trailing dot)
    comparisonChecks(chain, -1, 1, NameComparisonResult::COMMONANCESTOR);
    chain.clear();

    // Partial match, search stopped in the subtree below the matching node
    // after following a right branch.
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              tree.find(Name("z.d.e.f"), &expected_node));
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              tree.find(Name("zz.d.e.f"), &crbtnode, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // zz > z, 1 = # labels of "." (trailing dot)
    comparisonChecks(chain, 1, 1, NameComparisonResult::COMMONANCESTOR);
    chain.clear();

    // Partial match, search stopped at a node for a super domain of the
    // search name in the subtree below the matching node.
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              tree.find(Name("w.y.d.e.f"), &expected_node));
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              tree.find(Name("y.d.e.f"), &crbtnode, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // y < w.y, 2 = # labels of "y."
    comparisonChecks(chain, -1, 2, NameComparisonResult::SUPERDOMAIN);
    chain.clear();

    // Partial match, search stopped at a node that share a common ancestor
    // with the search name in the subtree below the matching node.
    // (the expected node is the same as the previous case)
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              tree.find(Name("z.y.d.e.f"), &crbtnode, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // z.y > w.y, 2 = # labels of "y."
    comparisonChecks(chain, 1, 2, NameComparisonResult::COMMONANCESTOR);
    chain.clear();

    // Search stops in the highest level after following a left branch.
    EXPECT_EQ(RBTree<int>::EXACTMATCH, tree.find(Name("c"), &expected_node));
    EXPECT_EQ(RBTree<int>::NOTFOUND,
              tree.find(Name("bb"), &crbtnode, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // bb < c, 1 = # labels of "." (trailing dot)
    comparisonChecks(chain, -1, 1, NameComparisonResult::COMMONANCESTOR);
    chain.clear();

    // Search stops in the highest level after following a right branch.
    // (the expected node is the same as the previous case)
    EXPECT_EQ(RBTree<int>::NOTFOUND,
              tree.find(Name("d"), &crbtnode, chain));
    EXPECT_EQ(expected_node, chain.getLastComparedNode());
    // d > c, 1 = # labels of "." (trailing dot)
    comparisonChecks(chain, 1, 1, NameComparisonResult::COMMONANCESTOR);
    chain.clear();
}

TEST_F(RBTreeTest, dumpTree) {
    std::ostringstream str;
    std::ostringstream str2;
    rbtree.dumpTree(str);
    str2 << "tree has 14 node(s)\n"
            "b. (black) [subtreeroot]\n"
            "     a. (black)\n"
            "          NULL\n"
            "          NULL\n"
            "     d.e.f. (black) [invisible]\n"
            "          begin down from d.e.f.\n"
            "          w.y. (black) [invisible] [subtreeroot]\n"
            "               begin down from w.y.\n"
            "               p. (black) [subtreeroot]\n"
            "                    o. (red)\n"
            "                         NULL\n"
            "                         NULL\n"
            "                    q. (red)\n"
            "                         NULL\n"
            "                         NULL\n"
            "               end down from w.y.\n"
            "               x. (red)\n"
            "                    NULL\n"
            "                    NULL\n"
            "               z. (red)\n"
            "                    begin down from z.\n"
            "                    j. (black) [subtreeroot]\n"
            "                         NULL\n"
            "                         NULL\n"
            "                    end down from z.\n"
            "                    NULL\n"
            "                    NULL\n"
            "          end down from d.e.f.\n"
            "          c. (red)\n"
            "               NULL\n"
            "               NULL\n"
            "          g.h. (red)\n"
            "               begin down from g.h.\n"
            "               i. (black) [subtreeroot]\n"
            "                    NULL\n"
            "                    k. (red)\n"
            "                         NULL\n"
            "                         NULL\n"
            "               end down from g.h.\n"
            "               NULL\n"
            "               NULL\n";
    EXPECT_EQ(str2.str(), str.str());
}

TEST_F(RBTreeTest, swap) {
    // Store info about the first tree
    std::ostringstream str1;
    rbtree.dumpTree(str1);
    size_t count1(rbtree.getNodeCount());

    // Create second one and store state
    RBTree<int> tree2;
    RBNode<int>* node;
    tree2.insert(Name("second"), &node);
    std::ostringstream str2;
    tree2.dumpTree(str2);

    // Swap them
    ASSERT_NO_THROW(tree2.swap(rbtree));

    // Check their sizes
    ASSERT_EQ(1, rbtree.getNodeCount());
    ASSERT_EQ(count1, tree2.getNodeCount());

    // And content
    std::ostringstream out;
    rbtree.dumpTree(out);
    ASSERT_EQ(str2.str(), out.str());
    out.str("");
    tree2.dumpTree(out);
    ASSERT_EQ(str1.str(), out.str());
}

// Matching in the "root zone" may be special (e.g. there's no parent,
// any domain names should be considered a subdomain of it), so it makes
// sense to test cases with the root zone explicitly.
TEST_F(RBTreeTest, root) {
    RBTree<int> root;
    root.insert(Name::ROOT_NAME(), &rbtnode);
    rbtnode->setData(RBNode<int>::NodeDataPtr(new int(1)));

    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              root.find(Name::ROOT_NAME(), &crbtnode));
    EXPECT_EQ(rbtnode, crbtnode);
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              root.find(Name("example.com"), &crbtnode));
    EXPECT_EQ(rbtnode, crbtnode);

    // Insert a new name that better matches the query name.  find() should
    // find the better one.
    root.insert(Name("com"), &rbtnode);
    rbtnode->setData(RBNode<int>::NodeDataPtr(new int(2)));
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              root.find(Name("example.com"), &crbtnode));
    EXPECT_EQ(rbtnode, crbtnode);

    // Perform the same tests for the tree that allows matching against empty
    // nodes.
    RBTree<int> root_emptyok(true);
    root_emptyok.insert(Name::ROOT_NAME(), &rbtnode);
    EXPECT_EQ(RBTree<int>::EXACTMATCH,
              root_emptyok.find(Name::ROOT_NAME(), &crbtnode));
    EXPECT_EQ(rbtnode, crbtnode);
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              root_emptyok.find(Name("example.com"), &crbtnode));
    EXPECT_EQ(rbtnode, crbtnode);

    root.insert(Name("com"), &rbtnode);
    EXPECT_EQ(RBTree<int>::PARTIALMATCH,
              root.find(Name("example.com"), &crbtnode));
    EXPECT_EQ(rbtnode, crbtnode);
}
}