ZobristHashTest.cpp

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00001 //---------------------------------------------------------------------------
00002 /** @file ZobristHashTest.cpp
00003  */
00004 //---------------------------------------------------------------------------
00005 
00006 #include <boost/test/auto_unit_test.hpp>
00007 
00008 #include "ZobristHash.hpp"
00009 
00010 using namespace benzene;
00011 
00012 //---------------------------------------------------------------------------
00013 
00014 namespace {
00015 
00016 BOOST_AUTO_TEST_CASE(ZobristHash_InitializationAndUpdates)
00017 {
00018     // Note: due to the probabilistic nature of Zobrist
00019     // hashing, it is possible that some of these tests
00020     // can fail. However, it should be extremely improbable,
00021     // to the point of never occuring in practice.
00022     // This is true only if USE_PREDEFINED_HASHES is false. 
00023 
00024     
00025     // check that base values do NOT differ
00026     ZobristHash zh1(5, 5);
00027     ZobristHash zh2(5, 5);
00028     BOOST_CHECK(zh1.Hash() == zh2.Hash());
00029     
00030     // check that updates change hash value, reset restores
00031     hash_t h1, h2, h3;
00032     h1 = zh1.Hash();
00033     zh1.Update(BLACK, FIRST_CELL);
00034     h2 = zh1.Hash();
00035     BOOST_CHECK(h1 != h2);
00036     zh1.Reset();
00037     BOOST_CHECK_EQUAL(h1, zh1.Hash());
00038     zh1.Update(WHITE, FIRST_CELL);
00039     h3 = zh1.Hash();
00040     BOOST_CHECK(h1 != h3);
00041     BOOST_CHECK(h2 != h3);
00042     zh1.Update(WHITE, FIRST_CELL);
00043     BOOST_CHECK_EQUAL(h1, zh1.Hash());
00044     zh1.Update(BLACK, FIRST_CELL);
00045     zh1.Update(WHITE, FIRST_CELL);
00046     BOOST_CHECK(h1 != zh1.Hash());
00047     BOOST_CHECK(h2 != zh1.Hash());
00048     BOOST_CHECK(h3 != zh1.Hash());
00049     zh1.Update(BLACK, FIRST_CELL);
00050     BOOST_CHECK_EQUAL(h3, zh1.Hash());
00051     
00052     // check that sequence of updates after reset
00053     // obtains same result as initialization
00054     bitset_t black, white;
00055     BOOST_REQUIRE(FIRST_CELL < FIRST_INVALID - 1);
00056     black.set(FIRST_CELL);
00057     black.set(FIRST_INVALID - 1);
00058     white.set(SWAP_PIECES);
00059     zh1 = ZobristHash(5, 5);
00060     zh1.Compute(black, white);
00061     h1 = zh1.Hash();
00062     zh1.Reset();
00063     zh1.Update(BLACK, FIRST_CELL);
00064     BOOST_CHECK(h1 != zh1.Hash());
00065     zh1.Update(WHITE, SWAP_PIECES);
00066     BOOST_CHECK(h1 != zh1.Hash());
00067     zh1.Update(BLACK, static_cast<HexPoint>(FIRST_INVALID - 1));
00068     BOOST_CHECK_EQUAL(h1, zh1.Hash());
00069     
00070     // check that compute gives same result as
00071     // Update and initialization
00072     zh1.Reset();
00073     zh1.Compute(black, white);
00074     BOOST_CHECK_EQUAL(h1, zh1.Hash());
00075     zh1.Reset();
00076     for (int i=0; i<FIRST_INVALID; ++i) {
00077         if (black.test(i)) 
00078             zh1.Update(BLACK, static_cast<HexPoint>(i));
00079         if (white.test(i))
00080             zh1.Update(WHITE, static_cast<HexPoint>(i));
00081     }
00082     BOOST_CHECK_EQUAL(h1, zh1.Hash());
00083 }
00084 
00085 }
00086 
00087 //---------------------------------------------------------------------------