From f5e3a447c8d6769cb58d17343fd97d39359532a8 Mon Sep 17 00:00:00 2001
From: Romain BOULLARD <romain.boullard@protonmail.com>
Date: Sun, 9 Aug 2026 15:33:12 +0200
Subject: [PATCH] SlotMap testing

---
 .../Include/Utils/Containers/SlotMap.hpp      |   4 +-
 Bigfoot/Tests/Utils/Containers/SlotMap.cpp    | 888 ++++++++++++++++++
 2 files changed, 890 insertions(+), 2 deletions(-)

diff --git a/Bigfoot/Sources/Utils/Include/Utils/Containers/SlotMap.hpp b/Bigfoot/Sources/Utils/Include/Utils/Containers/SlotMap.hpp
index 3ce2cfe..cf7de95 100644
--- a/Bigfoot/Sources/Utils/Include/Utils/Containers/SlotMap.hpp
+++ b/Bigfoot/Sources/Utils/Include/Utils/Containers/SlotMap.hpp
@@ -227,7 +227,7 @@ class DenseSlotMap: public SlotMapBase
     }
 
     [[nodiscard]]
-    std::size_t GetCapacity() const
+    std::size_t Capacity() const
     {
         return m_data.capacity();
     }
@@ -753,7 +753,7 @@ class StableSlotMap: public SlotMapBase
     }
 
     [[nodiscard]]
-    std::size_t GetCapacity() const
+    std::size_t Capacity() const
     {
         return m_pages.size() * PAGE_SIZE;
     }
diff --git a/Bigfoot/Tests/Utils/Containers/SlotMap.cpp b/Bigfoot/Tests/Utils/Containers/SlotMap.cpp
index 82ec1ac..b7d18cb 100644
--- a/Bigfoot/Tests/Utils/Containers/SlotMap.cpp
+++ b/Bigfoot/Tests/Utils/Containers/SlotMap.cpp
@@ -111,6 +111,17 @@ TYPED_TEST(SlotMapFixture, Has_ReturnFalseIfSlotMapDoesNotHaveTheKey)
 
 /****************************************************************************************/
 
+TYPED_TEST(SlotMapFixture, Has_ReturnFalseForStaleKey)
+{
+    const SlotMapKey staleKey = this->m_slotMap.Insert(42);
+    this->m_slotMap.Remove(staleKey);
+    std::ignore = this->m_slotMap.Insert(69);
+
+    EXPECT_FALSE(this->m_slotMap.Has(staleKey));
+}
+
+/****************************************************************************************/
+
 TYPED_TEST(SlotMapFixture, Size_ShouldReturnTheSizeOfTheSlotMap)
 {
     EXPECT_EQ(this->m_slotMap.Size(), 0);
@@ -147,4 +158,881 @@ TYPED_TEST(SlotMapFixture, Empty_ShouldReturnFalseIfTheSlotMapIsNotEmpty)
     EXPECT_FALSE(this->m_slotMap.Empty());
     this->m_slotMap.Remove(key2);
 }
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Insert_ShouldReturnAValidSlotKey)
+{
+    EXPECT_TRUE(this->m_slotMap.Insert(42).Valid());
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Insert_ShouldRecycleIndicesWhenPossible)
+{
+    const SlotMapKey key1 = this->m_slotMap.Insert(42);
+    const SlotMapKey key2 = this->m_slotMap.Insert(69);
+    
+    this->m_slotMap.Remove(key1);
+    this->m_slotMap.Remove(key2);
+
+    const SlotMapKey key11 = this->m_slotMap.Insert(42);
+    const SlotMapKey key21 = this->m_slotMap.Insert(69);
+
+    EXPECT_EQ(key1.GetVersion() + 1, key11.GetVersion());
+    EXPECT_EQ(key1.GetIndex(), key21.GetIndex()); //LIFO
+
+    EXPECT_EQ(key2.GetVersion() + 1, key21.GetVersion());
+    EXPECT_EQ(key2.GetIndex(), key11.GetIndex());  //LIFO
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Get_ShouldReturnTheValue)
+{
+    const SlotMapKey key = this->m_slotMap.Insert(42);
+    EXPECT_EQ(*this->m_slotMap.Get(key), 42);
+    EXPECT_EQ(*const_cast<const TypeParam&>(this->m_slotMap).Get(key), 42);
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Get_ShouldNullptrIfTheValueIsNotInMap)
+{
+    const SlotMapKey key {1, 0};
+    EXPECT_EQ(this->m_slotMap.Get(key), nullptr);
+    EXPECT_EQ(const_cast<const TypeParam&>(this->m_slotMap).Get(key), nullptr);
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Get_ShouldReturnNullptrForStaleKey)
+{
+    const SlotMapKey staleKey = this->m_slotMap.Insert(42);
+    this->m_slotMap.Remove(staleKey);
+    std::ignore = this->m_slotMap.Insert(69);
+
+    EXPECT_EQ(this->m_slotMap.Get(staleKey), nullptr);
+    EXPECT_EQ(const_cast<const TypeParam&>(this->m_slotMap).Get(staleKey), nullptr);
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Remove_ShouldRemoveTheValue)
+{
+    const SlotMapKey key = this->m_slotMap.Insert(42);
+    EXPECT_TRUE(this->m_slotMap.Has(key));
+    this->m_slotMap.Remove(key);
+    EXPECT_FALSE(this->m_slotMap.Has(key));
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Remove_ShouldBeANoOpForStaleKey)
+{
+    const SlotMapKey staleKey = this->m_slotMap.Insert(42);
+    this->m_slotMap.Remove(staleKey);
+    const SlotMapKey freshKey = this->m_slotMap.Insert(69);
+
+    this->m_slotMap.Remove(staleKey);
+
+    EXPECT_TRUE(this->m_slotMap.Has(freshKey));
+    EXPECT_EQ(*this->m_slotMap.Get(freshKey), 69);
+    EXPECT_EQ(this->m_slotMap.Size(), 1);
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Reset_ShouldClearTheMapAndOldKeysAreValid)
+{
+    const SlotMapKey key1 = this->m_slotMap.Insert(42);
+    const SlotMapKey key2 = this->m_slotMap.Insert(69);
+
+    this->m_slotMap.Reset();
+
+    EXPECT_EQ(this->m_slotMap.Size(), 0);
+    EXPECT_TRUE(this->m_slotMap.Empty());
+
+    EXPECT_FALSE(this->m_slotMap.Has(key1));
+    EXPECT_FALSE(this->m_slotMap.Has(key2));
+
+    EXPECT_EQ(this->m_slotMap.Insert(42), key1);
+    EXPECT_EQ(this->m_slotMap.Insert(69), key2);
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Clear_ShouldClearTheMapAndOldKeysAreInvalid)
+{
+    const SlotMapKey key1 = this->m_slotMap.Insert(42);
+    const SlotMapKey key2 = this->m_slotMap.Insert(69);
+
+    this->m_slotMap.Clear();
+
+    EXPECT_EQ(this->m_slotMap.Size(), 0);
+    EXPECT_TRUE(this->m_slotMap.Empty());
+
+    EXPECT_FALSE(this->m_slotMap.Has(key1));
+    EXPECT_FALSE(this->m_slotMap.Has(key2));
+
+    EXPECT_NE(this->m_slotMap.Insert(42), key1);
+    EXPECT_NE(this->m_slotMap.Insert(69), key2);
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, Iterator)
+{
+    EXPECT_EQ(this->m_slotMap.begin(), this->m_slotMap.end());
+
+    std::ignore = this->m_slotMap.Insert(1);
+    const SlotMapKey key2 = this->m_slotMap.Insert(2);
+    std::ignore = this->m_slotMap.Insert(3);
+
+    // Forward traversal follows insertion order
+    std::uint32_t expected = 1;
+    for (auto it = this->m_slotMap.begin(); it != this->m_slotMap.end(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        ++expected;
+    }
+
+    // Pre-increment advances and returns *this
+    auto preIt = this->m_slotMap.begin();
+    auto& preIncrementResult = ++preIt;
+    EXPECT_EQ(&preIncrementResult, &preIt);
+    EXPECT_EQ(*preIt, 2);
+
+    // Post-increment advances but returns the old value
+    auto postIt = this->m_slotMap.begin();
+    const auto postIncrementResult = postIt++;
+    EXPECT_EQ(*postIncrementResult, 1);
+    EXPECT_EQ(*postIt, 2);
+
+    // Pre-decrement retreats and returns *this
+    auto preDecIt = this->m_slotMap.end();
+    --preDecIt;   // now at 3
+    auto& preDecrementResult = --preDecIt;   // now at 2
+    EXPECT_EQ(&preDecrementResult, &preDecIt);
+    EXPECT_EQ(*preDecIt, 2);
+
+    // Post-decrement retreats but returns the old value
+    auto postDecIt = this->m_slotMap.end();
+    --postDecIt;   // now at 3
+    const auto postDecrementResult = postDecIt--;
+    EXPECT_EQ(*postDecrementResult, 3);
+    EXPECT_EQ(*postDecIt, 2);
+
+    // Removed slots are skipped during traversal
+    this->m_slotMap.Remove(key2);
+
+    std::size_t count = 0;
+    std::uint32_t sum = 0;
+    for (const std::uint32_t value: this->m_slotMap)
+    {
+        ++count;
+        sum += value;
+    }
+    EXPECT_EQ(count, 2);
+    EXPECT_EQ(sum, 4);
+
+    // Multi-page traversal: StableSlotMap's PAGE_SIZE is 64, so 100 elements force it to span pages
+    this->m_slotMap.Reset();
+
+    constexpr std::uint32_t elementCount = 100;
+    eastl::array<SlotMapKey, elementCount> keys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        keys[value] = this->m_slotMap.Insert(value);
+    }
+
+    expected = 0;
+    for (const std::uint32_t value: this->m_slotMap)
+    {
+        EXPECT_EQ(value, expected);
+        ++expected;
+    }
+    EXPECT_EQ(expected, elementCount);
+
+    // Explicitly cross the page boundary (index 63 -> 64) forward and backward
+    auto boundaryIt = this->m_slotMap.begin();
+    for (std::uint32_t step = 0; step < 63; ++step)
+    {
+        ++boundaryIt;
+    }
+    EXPECT_EQ(*boundaryIt, 63);
+    ++boundaryIt;
+    EXPECT_EQ(*boundaryIt, 64);
+    --boundaryIt;
+    EXPECT_EQ(*boundaryIt, 63);
+
+    // Pre/post-increment/decrement across the boundary
+    auto preBoundaryIt = this->m_slotMap.begin();
+    auto& preBoundaryIncrementResult = ++preBoundaryIt;
+    EXPECT_EQ(&preBoundaryIncrementResult, &preBoundaryIt);
+    EXPECT_EQ(*preBoundaryIt, 1);
+
+    auto postBoundaryIt = this->m_slotMap.begin();
+    const auto postBoundaryIncrementResult = postBoundaryIt++;
+    EXPECT_EQ(*postBoundaryIncrementResult, 0);
+    EXPECT_EQ(*postBoundaryIt, 1);
+
+    auto preBoundaryDecIt = this->m_slotMap.end();
+    --preBoundaryDecIt;   // now at 99
+    auto& preBoundaryDecrementResult = --preBoundaryDecIt;   // now at 98
+    EXPECT_EQ(&preBoundaryDecrementResult, &preBoundaryDecIt);
+    EXPECT_EQ(*preBoundaryDecIt, 98);
+
+    auto postBoundaryDecIt = this->m_slotMap.end();
+    --postBoundaryDecIt;   // now at 99
+    const auto postBoundaryDecrementResult = postBoundaryDecIt--;
+    EXPECT_EQ(*postBoundaryDecrementResult, 99);
+    EXPECT_EQ(*postBoundaryDecIt, 98);
+
+    // Remove elements straddling the boundary and check the holes are skipped
+    this->m_slotMap.Remove(keys[63]);
+    this->m_slotMap.Remove(keys[64]);
+
+    count = 0;
+    for (const std::uint32_t value: this->m_slotMap)
+    {
+        EXPECT_NE(value, 63);
+        EXPECT_NE(value, 64);
+        ++count;
+    }
+    EXPECT_EQ(count, elementCount - 2);
+
+    // A fully empty leading page must be skipped by begin()/SeekFirstFrom
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> leadingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        leadingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 0; value < 64; ++value)
+    {
+        this->m_slotMap.Remove(leadingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (const std::uint32_t value: this->m_slotMap)
+    {
+        ++count;
+        sum += value;
+    }
+    EXPECT_EQ(count, elementCount - 64);
+    EXPECT_EQ(sum, 2934u);   // 64 + 65 + ... + 99
+
+    // A fully empty trailing page must be skipped when retreating past it
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> trailingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        trailingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 64; value < elementCount; ++value)
+    {
+        this->m_slotMap.Remove(trailingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (const std::uint32_t value: this->m_slotMap)
+    {
+        ++count;
+        sum += value;
+    }
+    EXPECT_EQ(count, 64u);
+    EXPECT_EQ(sum, 2016u);   // 0 + 1 + ... + 63
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, ConstIterator)
+{
+    const TypeParam& constMap = this->m_slotMap;
+
+    // const_iterator is reachable two ways: cbegin()/cend(), or begin()/end() on a const object
+    EXPECT_EQ(this->m_slotMap.cbegin(), this->m_slotMap.cend());
+    EXPECT_EQ(constMap.begin(), constMap.end());
+
+    std::ignore = this->m_slotMap.Insert(1);
+    const SlotMapKey key2 = this->m_slotMap.Insert(2);
+    std::ignore = this->m_slotMap.Insert(3);
+
+    std::uint32_t expected = 1;
+    for (auto it = this->m_slotMap.cbegin(); it != this->m_slotMap.cend(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        ++expected;
+    }
+
+    expected = 1;
+    for (auto it = constMap.begin(); it != constMap.end(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        ++expected;
+    }
+
+    // Pre-increment advances and returns *this
+    auto preIt = this->m_slotMap.cbegin();
+    auto& preIncrementResult = ++preIt;
+    EXPECT_EQ(&preIncrementResult, &preIt);
+    EXPECT_EQ(*preIt, 2);
+
+    // Post-increment advances but returns the old value
+    auto postIt = this->m_slotMap.cbegin();
+    const auto postIncrementResult = postIt++;
+    EXPECT_EQ(*postIncrementResult, 1);
+    EXPECT_EQ(*postIt, 2);
+
+    // Pre-decrement retreats and returns *this
+    auto preDecIt = this->m_slotMap.cend();
+    --preDecIt;   // now at 3
+    auto& preDecrementResult = --preDecIt;   // now at 2
+    EXPECT_EQ(&preDecrementResult, &preDecIt);
+    EXPECT_EQ(*preDecIt, 2);
+
+    // Post-decrement retreats but returns the old value
+    auto postDecIt = this->m_slotMap.cend();
+    --postDecIt;   // now at 3
+    const auto postDecrementResult = postDecIt--;
+    EXPECT_EQ(*postDecrementResult, 3);
+    EXPECT_EQ(*postDecIt, 2);
+
+    // Removed slots are skipped identically through cbegin()/cend() and the const-object overloads
+    this->m_slotMap.Remove(key2);
+
+    std::size_t count = 0;
+    std::uint32_t sum = 0;
+    for (auto it = this->m_slotMap.cbegin(); it != this->m_slotMap.cend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 2);
+    EXPECT_EQ(sum, 4);
+
+    count = 0;
+    sum = 0;
+    for (auto it = constMap.begin(); it != constMap.end(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 2);
+    EXPECT_EQ(sum, 4);
+
+    // Multi-page traversal: StableSlotMap's PAGE_SIZE is 64, so 100 elements force it to span pages
+    this->m_slotMap.Reset();
+
+    constexpr std::uint32_t elementCount = 100;
+    eastl::array<SlotMapKey, elementCount> keys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        keys[value] = this->m_slotMap.Insert(value);
+    }
+
+    expected = 0;
+    for (auto it = this->m_slotMap.cbegin(); it != this->m_slotMap.cend(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        ++expected;
+    }
+    EXPECT_EQ(expected, elementCount);
+
+    // Explicitly cross the page boundary (index 63 -> 64) forward and backward
+    auto boundaryIt = this->m_slotMap.cbegin();
+    for (std::uint32_t step = 0; step < 63; ++step)
+    {
+        ++boundaryIt;
+    }
+    EXPECT_EQ(*boundaryIt, 63);
+    ++boundaryIt;
+    EXPECT_EQ(*boundaryIt, 64);
+    --boundaryIt;
+    EXPECT_EQ(*boundaryIt, 63);
+
+    // Pre/post-increment/decrement across the boundary
+    auto preBoundaryIt = this->m_slotMap.cbegin();
+    auto& preBoundaryIncrementResult = ++preBoundaryIt;
+    EXPECT_EQ(&preBoundaryIncrementResult, &preBoundaryIt);
+    EXPECT_EQ(*preBoundaryIt, 1);
+
+    auto postBoundaryIt = this->m_slotMap.cbegin();
+    const auto postBoundaryIncrementResult = postBoundaryIt++;
+    EXPECT_EQ(*postBoundaryIncrementResult, 0);
+    EXPECT_EQ(*postBoundaryIt, 1);
+
+    auto preBoundaryDecIt = this->m_slotMap.cend();
+    --preBoundaryDecIt;   // now at 99
+    auto& preBoundaryDecrementResult = --preBoundaryDecIt;   // now at 98
+    EXPECT_EQ(&preBoundaryDecrementResult, &preBoundaryDecIt);
+    EXPECT_EQ(*preBoundaryDecIt, 98);
+
+    auto postBoundaryDecIt = this->m_slotMap.cend();
+    --postBoundaryDecIt;   // now at 99
+    const auto postBoundaryDecrementResult = postBoundaryDecIt--;
+    EXPECT_EQ(*postBoundaryDecrementResult, 99);
+    EXPECT_EQ(*postBoundaryDecIt, 98);
+
+    // Remove elements straddling the boundary and check the holes are skipped
+    this->m_slotMap.Remove(keys[63]);
+    this->m_slotMap.Remove(keys[64]);
+
+    count = 0;
+    for (auto it = this->m_slotMap.cbegin(); it != this->m_slotMap.cend(); ++it)
+    {
+        EXPECT_NE(*it, 63);
+        EXPECT_NE(*it, 64);
+        ++count;
+    }
+    EXPECT_EQ(count, elementCount - 2);
+
+    // A fully empty leading page must be skipped by cbegin()/SeekFirstFrom
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> leadingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        leadingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 0; value < 64; ++value)
+    {
+        this->m_slotMap.Remove(leadingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (auto it = this->m_slotMap.cbegin(); it != this->m_slotMap.cend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, elementCount - 64);
+    EXPECT_EQ(sum, 2934u);   // 64 + 65 + ... + 99
+
+    // A fully empty trailing page must be skipped when retreating past it
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> trailingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        trailingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 64; value < elementCount; ++value)
+    {
+        this->m_slotMap.Remove(trailingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (auto it = this->m_slotMap.cbegin(); it != this->m_slotMap.cend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 64u);
+    EXPECT_EQ(sum, 2016u);   // 0 + 1 + ... + 63
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, ReverseIterator)
+{
+    EXPECT_EQ(this->m_slotMap.rbegin(), this->m_slotMap.rend());
+
+    std::ignore = this->m_slotMap.Insert(1);
+    const SlotMapKey key2 = this->m_slotMap.Insert(2);
+    std::ignore = this->m_slotMap.Insert(3);
+
+    // Reverse traversal mirrors insertion order
+    std::uint32_t expected = 3;
+    for (auto it = this->m_slotMap.rbegin(); it != this->m_slotMap.rend(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        --expected;
+    }
+
+    // Pre-increment advances and returns *this
+    auto preIt = this->m_slotMap.rbegin();
+    auto& preIncrementResult = ++preIt;
+    EXPECT_EQ(&preIncrementResult, &preIt);
+    EXPECT_EQ(*preIt, 2);
+
+    // Post-increment advances but returns the old value
+    auto postIt = this->m_slotMap.rbegin();
+    const auto postIncrementResult = postIt++;
+    EXPECT_EQ(*postIncrementResult, 3);
+    EXPECT_EQ(*postIt, 2);
+
+    // Pre-decrement retreats and returns *this
+    auto preDecIt = this->m_slotMap.rend();
+    --preDecIt;   // now at 1
+    auto& preDecrementResult = --preDecIt;   // now at 2
+    EXPECT_EQ(&preDecrementResult, &preDecIt);
+    EXPECT_EQ(*preDecIt, 2);
+
+    // Post-decrement retreats but returns the old value
+    auto postDecIt = this->m_slotMap.rend();
+    --postDecIt;   // now at 1
+    const auto postDecrementResult = postDecIt--;
+    EXPECT_EQ(*postDecrementResult, 1);
+    EXPECT_EQ(*postDecIt, 2);
+
+    // Removed slots are skipped during traversal
+    this->m_slotMap.Remove(key2);
+
+    std::size_t count = 0;
+    std::uint32_t sum = 0;
+    for (auto it = this->m_slotMap.rbegin(); it != this->m_slotMap.rend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 2);
+    EXPECT_EQ(sum, 4);
+
+    // Multi-page traversal: StableSlotMap's PAGE_SIZE is 64, so 100 elements force it to span pages
+    this->m_slotMap.Reset();
+
+    constexpr std::uint32_t elementCount = 100;
+    eastl::array<SlotMapKey, elementCount> keys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        keys[value] = this->m_slotMap.Insert(value);
+    }
+
+    expected = elementCount - 1;
+    for (auto it = this->m_slotMap.rbegin(); it != this->m_slotMap.rend(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        --expected;
+    }
+
+    // Explicitly cross the page boundary (value 64 -> 63) forward and backward
+    auto boundaryIt = this->m_slotMap.rbegin();
+    while (*boundaryIt != 64)
+    {
+        ++boundaryIt;
+    }
+    ++boundaryIt;
+    EXPECT_EQ(*boundaryIt, 63);
+    --boundaryIt;
+    EXPECT_EQ(*boundaryIt, 64);
+
+    // Pre/post-increment/decrement across the boundary
+    auto preBoundaryIt = this->m_slotMap.rbegin();
+    auto& preBoundaryIncrementResult = ++preBoundaryIt;
+    EXPECT_EQ(&preBoundaryIncrementResult, &preBoundaryIt);
+    EXPECT_EQ(*preBoundaryIt, 98);
+
+    auto postBoundaryIt = this->m_slotMap.rbegin();
+    const auto postBoundaryIncrementResult = postBoundaryIt++;
+    EXPECT_EQ(*postBoundaryIncrementResult, 99);
+    EXPECT_EQ(*postBoundaryIt, 98);
+
+    auto preBoundaryDecIt = this->m_slotMap.rend();
+    --preBoundaryDecIt;   // now at 0
+    auto& preBoundaryDecrementResult = --preBoundaryDecIt;   // now at 1
+    EXPECT_EQ(&preBoundaryDecrementResult, &preBoundaryDecIt);
+    EXPECT_EQ(*preBoundaryDecIt, 1);
+
+    auto postBoundaryDecIt = this->m_slotMap.rend();
+    --postBoundaryDecIt;   // now at 0
+    const auto postBoundaryDecrementResult = postBoundaryDecIt--;
+    EXPECT_EQ(*postBoundaryDecrementResult, 0);
+    EXPECT_EQ(*postBoundaryDecIt, 1);
+
+    // Remove elements straddling the boundary and check the holes are skipped
+    this->m_slotMap.Remove(keys[63]);
+    this->m_slotMap.Remove(keys[64]);
+
+    count = 0;
+    for (auto it = this->m_slotMap.rbegin(); it != this->m_slotMap.rend(); ++it)
+    {
+        EXPECT_NE(*it, 63);
+        EXPECT_NE(*it, 64);
+        ++count;
+    }
+    EXPECT_EQ(count, elementCount - 2);
+
+    // A fully empty leading page must be skipped when retreating past it (rend() side)
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> leadingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        leadingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 0; value < 64; ++value)
+    {
+        this->m_slotMap.Remove(leadingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (auto it = this->m_slotMap.rbegin(); it != this->m_slotMap.rend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, elementCount - 64);
+    EXPECT_EQ(sum, 2934u);   // 64 + 65 + ... + 99
+
+    // A fully empty trailing page must be skipped by rbegin()/SeekLastFrom
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> trailingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        trailingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 64; value < elementCount; ++value)
+    {
+        this->m_slotMap.Remove(trailingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (auto it = this->m_slotMap.rbegin(); it != this->m_slotMap.rend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 64u);
+    EXPECT_EQ(sum, 2016u);   // 0 + 1 + ... + 63
+}
+
+/****************************************************************************************/
+
+TYPED_TEST(SlotMapFixture, ConstReverseIterator)
+{
+    const TypeParam& constMap = this->m_slotMap;
+
+    // const_reverse_iterator is reachable two ways: crbegin()/crend(), or rbegin()/rend() on a
+    // const object
+    EXPECT_EQ(this->m_slotMap.crbegin(), this->m_slotMap.crend());
+    EXPECT_EQ(constMap.rbegin(), constMap.rend());
+
+    std::ignore = this->m_slotMap.Insert(1);
+    const SlotMapKey key2 = this->m_slotMap.Insert(2);
+    std::ignore = this->m_slotMap.Insert(3);
+
+    std::uint32_t expected = 3;
+    for (auto it = this->m_slotMap.crbegin(); it != this->m_slotMap.crend(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        --expected;
+    }
+
+    expected = 3;
+    for (auto it = constMap.rbegin(); it != constMap.rend(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        --expected;
+    }
+
+    // Pre-increment advances and returns *this
+    auto preIt = this->m_slotMap.crbegin();
+    auto& preIncrementResult = ++preIt;
+    EXPECT_EQ(&preIncrementResult, &preIt);
+    EXPECT_EQ(*preIt, 2);
+
+    // Post-increment advances but returns the old value
+    auto postIt = this->m_slotMap.crbegin();
+    const auto postIncrementResult = postIt++;
+    EXPECT_EQ(*postIncrementResult, 3);
+    EXPECT_EQ(*postIt, 2);
+
+    // Pre-decrement retreats and returns *this
+    auto preDecIt = this->m_slotMap.crend();
+    --preDecIt;   // now at 1
+    auto& preDecrementResult = --preDecIt;   // now at 2
+    EXPECT_EQ(&preDecrementResult, &preDecIt);
+    EXPECT_EQ(*preDecIt, 2);
+
+    // Post-decrement retreats but returns the old value
+    auto postDecIt = this->m_slotMap.crend();
+    --postDecIt;   // now at 1
+    const auto postDecrementResult = postDecIt--;
+    EXPECT_EQ(*postDecrementResult, 1);
+    EXPECT_EQ(*postDecIt, 2);
+
+    // Removed slots are skipped identically through crbegin()/crend() and the const-object overloads
+    this->m_slotMap.Remove(key2);
+
+    std::size_t count = 0;
+    std::uint32_t sum = 0;
+    for (auto it = this->m_slotMap.crbegin(); it != this->m_slotMap.crend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 2);
+    EXPECT_EQ(sum, 4);
+
+    count = 0;
+    sum = 0;
+    for (auto it = constMap.rbegin(); it != constMap.rend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 2);
+    EXPECT_EQ(sum, 4);
+
+    // Multi-page traversal: StableSlotMap's PAGE_SIZE is 64, so 100 elements force it to span pages
+    this->m_slotMap.Reset();
+
+    constexpr std::uint32_t elementCount = 100;
+    eastl::array<SlotMapKey, elementCount> keys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        keys[value] = this->m_slotMap.Insert(value);
+    }
+
+    expected = elementCount - 1;
+    for (auto it = this->m_slotMap.crbegin(); it != this->m_slotMap.crend(); ++it)
+    {
+        EXPECT_EQ(*it, expected);
+        --expected;
+    }
+
+    // Explicitly cross the page boundary (value 64 -> 63) forward and backward
+    auto boundaryIt = this->m_slotMap.crbegin();
+    while (*boundaryIt != 64)
+    {
+        ++boundaryIt;
+    }
+    ++boundaryIt;
+    EXPECT_EQ(*boundaryIt, 63);
+    --boundaryIt;
+    EXPECT_EQ(*boundaryIt, 64);
+
+    // Pre/post-increment/decrement across the boundary
+    auto preBoundaryIt = this->m_slotMap.crbegin();
+    auto& preBoundaryIncrementResult = ++preBoundaryIt;
+    EXPECT_EQ(&preBoundaryIncrementResult, &preBoundaryIt);
+    EXPECT_EQ(*preBoundaryIt, 98);
+
+    auto postBoundaryIt = this->m_slotMap.crbegin();
+    const auto postBoundaryIncrementResult = postBoundaryIt++;
+    EXPECT_EQ(*postBoundaryIncrementResult, 99);
+    EXPECT_EQ(*postBoundaryIt, 98);
+
+    auto preBoundaryDecIt = this->m_slotMap.crend();
+    --preBoundaryDecIt;   // now at 0
+    auto& preBoundaryDecrementResult = --preBoundaryDecIt;   // now at 1
+    EXPECT_EQ(&preBoundaryDecrementResult, &preBoundaryDecIt);
+    EXPECT_EQ(*preBoundaryDecIt, 1);
+
+    auto postBoundaryDecIt = this->m_slotMap.crend();
+    --postBoundaryDecIt;   // now at 0
+    const auto postBoundaryDecrementResult = postBoundaryDecIt--;
+    EXPECT_EQ(*postBoundaryDecrementResult, 0);
+    EXPECT_EQ(*postBoundaryDecIt, 1);
+
+    // Remove elements straddling the boundary and check the holes are skipped
+    this->m_slotMap.Remove(keys[63]);
+    this->m_slotMap.Remove(keys[64]);
+
+    count = 0;
+    for (auto it = this->m_slotMap.crbegin(); it != this->m_slotMap.crend(); ++it)
+    {
+        EXPECT_NE(*it, 63);
+        EXPECT_NE(*it, 64);
+        ++count;
+    }
+    EXPECT_EQ(count, elementCount - 2);
+
+    // A fully empty leading page must be skipped when retreating past it (crend() side)
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> leadingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        leadingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 0; value < 64; ++value)
+    {
+        this->m_slotMap.Remove(leadingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (auto it = this->m_slotMap.crbegin(); it != this->m_slotMap.crend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, elementCount - 64);
+    EXPECT_EQ(sum, 2934u);   // 64 + 65 + ... + 99
+
+    // A fully empty trailing page must be skipped by crbegin()/SeekLastFrom
+    this->m_slotMap.Reset();
+    eastl::array<SlotMapKey, elementCount> trailingKeys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        trailingKeys[value] = this->m_slotMap.Insert(value);
+    }
+    for (std::uint32_t value = 64; value < elementCount; ++value)
+    {
+        this->m_slotMap.Remove(trailingKeys[value]);
+    }
+
+    count = 0;
+    sum = 0;
+    for (auto it = this->m_slotMap.crbegin(); it != this->m_slotMap.crend(); ++it)
+    {
+        ++count;
+        sum += *it;
+    }
+    EXPECT_EQ(count, 64u);
+    EXPECT_EQ(sum, 2016u);   // 0 + 1 + ... + 63
+}
+
+/****************************************************************************************/
+
+class StableSlotMapFixture: public ::testing::Test
+{
+  protected:
+    StableSlotMap<std::uint32_t> m_slotMap;
+};
+
+/****************************************************************************************/
+
+TEST_F(StableSlotMapFixture, PointersAreStable)
+{
+    const SlotMapKey key = m_slotMap.Insert(42);
+    const std::uint32_t* const pointer = m_slotMap.Get(key);
+
+    // Inserting enough elements to span multiple pages (PAGE_SIZE is 64) must not move already
+    // -inserted data: unlike DenseSlotMap's contiguous eastl::vector, growth only appends new
+    // Page objects (each individually heap-allocated), it never reallocates existing ones.
+    constexpr std::uint32_t elementCount = 200;
+    eastl::array<SlotMapKey, elementCount> keys;
+    for (std::uint32_t value = 0; value < elementCount; ++value)
+    {
+        keys[value] = m_slotMap.Insert(value);
+    }
+
+    EXPECT_EQ(m_slotMap.Get(key), pointer);
+    EXPECT_EQ(*pointer, 42);
+
+    // Removing unrelated elements, including ones sharing the same page as key, must not move it
+    // either: Remove() only resets that slot's optional, it never compacts the page's array.
+    for (std::uint32_t value = 0; value < elementCount; value += 2)
+    {
+        m_slotMap.Remove(keys[value]);
+    }
+
+    EXPECT_EQ(m_slotMap.Get(key), pointer);
+    EXPECT_EQ(*pointer, 42);
+
+    // Re-inserting into the freed slots must not move it either
+    for (std::uint32_t value = 0; value < elementCount / 2; ++value)
+    {
+        std::ignore = m_slotMap.Insert(value);
+    }
+
+    EXPECT_EQ(m_slotMap.Get(key), pointer);
+    EXPECT_EQ(*pointer, 42);
+}
 }   // namespace Bigfoot