text: // Copyright (c) 2020 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 "chromeos/memory/userspace_swap/region.h"
  
  #include "testing/gtest/include/gtest/gtest.h"
  
  namespace chromeos {
  namespace memory {
  namespace userspace_swap {
  
  // This test validates the behavior of CalculateOverlap when a region and a
  // range don't overlap at all.
  TEST(Region, OverlapNone) {
    Region region(1000, 100);  // Region from [1000, 1100]
  
    // Calculate no overlap ahead of the region.
    Region range(900, 99);  // Range from [900,1000]
    RegionOverlap overlap = region.CalculateRegionOverlap(range);
    ASSERT_FALSE(overlap.before);
    ASSERT_FALSE(overlap.intersection);
    ASSERT_FALSE(overlap.after);
  
    // Calculate no overlap beyond the region.
    Region range2(1101, 99);  // Range from [1101, 1200]
    RegionOverlap overlap2 = region.CalculateRegionOverlap(range2);
    ASSERT_FALSE(overlap2.before);
    ASSERT_FALSE(overlap2.intersection);
    ASSERT_FALSE(overlap2.after);
  }
  
  // This test validates the behavior of CalculateOverlap when range fully covers
  // the region.
  TEST(Region, OverlapFull) {
    Region region(1000, 100);  // Region from [1000, 1100]
    Region range(900, 300);    // Range from [900,1200]
  
    // And the intersection->should be the same as region.
    RegionOverlap overlap = region.CalculateRegionOverlap(range);
    ASSERT_FALSE(overlap.before);
    ASSERT_FALSE(overlap.after);
    ASSERT_TRUE(overlap.intersection);
    EXPECT_EQ(overlap.intersection->address, region.address);
    EXPECT_EQ(overlap.intersection->length, region.length);
  }
  
  // This validates the behavior when the range overlaps from the start of the
  // range and the end piece of region remains.
  TEST(Region, OverlapEndRemains) {
    Region region(1000, 100);  // Region from [1000, 1100]
  
    Region range(900, 150);  // Range from [900,1050]
    RegionOverlap overlap = region.CalculateRegionOverlap(range);
  
    ASSERT_FALSE(overlap.before);
    ASSERT_TRUE(overlap.intersection);
    ASSERT_TRUE(overlap.after);
    EXPECT_EQ(overlap.intersection->address, region.address);
    EXPECT_EQ(overlap.intersection->length, 50u);
    EXPECT_EQ(overlap.after->length, 50u);
  }
  
  // This validates the behavior when the range overlaps from the end of the
  // range and the start piece of region remains.
  TEST(Region, OverlapStartRemains) {
    Region region(1000, 100);  // Region from [1000, 1100]
  
    Region range(1050, 150);  // Range from [1050,1200]
    RegionOverlap overlap = region.CalculateRegionOverlap(range);
  
    ASSERT_FALSE(overlap.after);
    ASSERT_TRUE(overlap.intersection);
    ASSERT_TRUE(overlap.before);
    EXPECT_EQ(overlap.intersection->address, region.address + 50);
    EXPECT_EQ(overlap.intersection->length, 50u);
    EXPECT_EQ(overlap.before->length, 50u);
  }
  
  // This test validates a range which is fully within a region.
  TEST(Region, OverlapWithinRegion) {
    Region region(1000, 100);  // Region from [1000, 1100]
  
    Region range(1050, 25);  // Range from [1050,1075]
    RegionOverlap overlap = region.CalculateRegionOverlap(range);
  
    ASSERT_TRUE(overlap.intersection);
    ASSERT_TRUE(overlap.before);
    ASSERT_TRUE(overlap.after);
    EXPECT_EQ(overlap.intersection->address, region.address + 50);
    EXPECT_EQ(overlap.intersection->length, 25u);
    EXPECT_EQ(overlap.before->length, 50u);
    EXPECT_EQ(overlap.after->length, 25u);
  }
  
  }  // namespace userspace_swap
  }  // namespace memory
  }  // namespace chromeos
  