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/*! \internal \file
 * \brief
 * Tests for the union-find implementation in unionfind.h.
 *
 * \author Teemu Murtola <teemu.murtola@gmail.com>
 * \ingroup module_trajectoryanalysis
 */
#include "gmxpre.h"

#include "gromacs/trajectoryanalysis/modules/unionfind.h"

#include <gmock/gmock.h>
#include <gtest/gtest.h>

namespace
{

/********************************************************************
 * Tests for UnionFinder
 */

TEST(UnionFinderTest, WorksEmpty)
{
    using ::testing::IsEmpty;
    gmx::UnionFinder finder;
    finder.init(0);
    EXPECT_THAT(finder.allSizes(), IsEmpty());
}

TEST(UnionFinderTest, BasicMerges)
{
    using ::testing::Each;
    using ::testing::UnorderedElementsAre;
    gmx::UnionFinder finder;
    finder.init(7);
    EXPECT_EQ(7U, finder.allSizes().size());
    EXPECT_THAT(finder.allSizes(), Each(1));
    finder.merge(0, 1);
    finder.merge(2, 3);
    finder.merge(0, 4);
    finder.merge(3, 5);
    EXPECT_THAT(finder.allSizes(), UnorderedElementsAre(3, 3, 1));
}

TEST(UnionFinderTest, LargerMerges)
{
    using ::testing::UnorderedElementsAre;
    gmx::UnionFinder finder;
    finder.init(7);
    finder.merge(0, 1);
    finder.merge(2, 3);
    finder.merge(4, 5);
    finder.merge(3, 5);
    finder.merge(1, 5);
    EXPECT_THAT(finder.allSizes(), UnorderedElementsAre(6, 1));
}

TEST(UnionFinderTest, LongRightMerge)
{
    using ::testing::ElementsAre;
    gmx::UnionFinder finder;
    finder.init(7);
    finder.merge(0, 1);
    finder.merge(1, 2);
    finder.merge(2, 3);
    finder.merge(3, 4);
    finder.merge(4, 5);
    finder.merge(5, 6);
    EXPECT_THAT(finder.allSizes(), ElementsAre(7));
}

TEST(UnionFinderTest, LongLeftMerge)
{
    using ::testing::ElementsAre;
    gmx::UnionFinder finder;
    finder.init(7);
    finder.merge(5, 6);
    finder.merge(4, 5);
    finder.merge(3, 4);
    finder.merge(2, 3);
    finder.merge(1, 2);
    finder.merge(0, 1);
    EXPECT_THAT(finder.allSizes(), ElementsAre(7));
}

/********************************************************************
 * Tests for MappedUnionFinder
 */

TEST(MappedUnionFinderTest, BasicMerges)
{
    using ::testing::Each;
    const int              mapping[] = { 1, 1, 2, 2, 4, 6 };
    gmx::MappedUnionFinder finder;
    finder.initWithGroupIndices(mapping);
    EXPECT_EQ(4U, finder.allSizes().size());
    EXPECT_THAT(finder.allSizes(), Each(1));
    finder.mergeGroups(1, 4);
    finder.mergeGroups(2, 6);
    EXPECT_EQ(2U, finder.allSizes().size());
    EXPECT_THAT(finder.allSizes(), Each(2));
}

} // namespace
