ProjectEleri/Plugins/DirectiveUtilities/Source/DirectiveUtilitiesTests/Private/Tests/DirectiveUtilArrayFunctionLibraryTest.cpp

// Copyright (c) 2026 Unreal Directive. Licensed under the MIT License.

#include "Libraries/DirectiveUtilArrayFunctionLibrary.h"
#include "Async/ParallelFor.h"
#include "Tests/DirectiveUtilTestObject.h"

#include <limits>
#include "Misc/AutomationTest.h"

namespace
{
	TArray<int32> BuildReferenceSample(const int32 SourceCount, const int32 Count, const int32 Seed)
	{
		TArray<int32> AvailableIndices;
		AvailableIndices.SetNumUninitialized(SourceCount);
		for (int32 Index = 0; Index < SourceCount; ++Index)
		{
			AvailableIndices[Index] = Index;
		}

		FRandomStream RandomStream(Seed);
		TArray<int32> Result;
		const int32 SampleCount = FMath::Min(SourceCount, Count);
		Result.Reserve(SampleCount);
		for (int32 SampleIndex = 0; SampleIndex < SampleCount; ++SampleIndex)
		{
			const int32 SelectedIndex = RandomStream.RandRange(0, AvailableIndices.Num() - 1);
			Result.Add(AvailableIndices[SelectedIndex]);
			AvailableIndices.RemoveAtSwap(SelectedIndex, 1, EAllowShrinking::No);
		}
		return Result;
	}

	TArray<int32> BuildReferenceDistinct(const TArray<int32>& Values)
	{
		TArray<int32> Result;
		for (const int32 Value : Values)
		{
			if (!Result.Contains(Value))
			{
				Result.Add(Value);
			}
		}
		return Result;
	}

	TArray<int32> BuildReferenceRemoval(
		const TArray<int32>& Values,
		const TArray<int32>& Indices)
	{
		TArray<int32> Result;
		Result.Reserve(Values.Num());
		for (int32 Index = 0; Index < Values.Num(); ++Index)
		{
			if (!Indices.Contains(Index))
			{
				Result.Add(Values[Index]);
			}
		}
		return Result;
	}
}

IMPLEMENT_SIMPLE_AUTOMATION_TEST(FDirectiveUtilArrayFunctionLibraryTest, "DirectiveUtilities.ArrayFunctionLibraryTests", EAutomationTestFlags::EditorContext | EAutomationTestFlags::ClientContext | EAutomationTestFlags::EngineFilter)

bool FDirectiveUtilArrayFunctionLibraryTest::RunTest(const FString& Parameters)
{
	UDirectiveUtilTestObject* TestObject = NewObject<UDirectiveUtilTestObject>();

	TestObject->TestArray = {1, 2, 3, 4, 5};

	FArrayProperty* ArrayProperty = FindFProperty<FArrayProperty>(UDirectiveUtilTestObject::StaticClass(), GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestArray));

	const int32 NextIndex = UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, 2, false);
	const int32 PreviousIndex = UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, 2, false);

	TestEqual("Array_NextIndex should return the next index in the array", NextIndex, 3);
	TestEqual("Array_PreviousIndex should return the previous index in the array", PreviousIndex, 1);

	const int32 NextIndexLooped = UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, 4, true);
	const int32 PreviousIndexLooped = UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, 0, true);

	TestEqual("Array_NextIndex should return the first index when looping", NextIndexLooped, 0);
	TestEqual("Array_PreviousIndex should return the last index when looping", PreviousIndexLooped, 4);

	const int32 NextIndexNonLooped = UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, 4, false);
	const int32 PreviousIndexNonLooped = UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, 0, false);

	TestEqual("Array_NextIndex should return the last index when not looping", NextIndexNonLooped, 4);
	TestEqual("Array_PreviousIndex should return the first index when not looping", PreviousIndexNonLooped, 0);

	const int32 NextIndexOutOfBounds = UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, 5, false);
	const int32 PreviousIndexOutOfBounds = UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, -1, false);

	TestEqual("Array_NextIndex should return the last index when out of bounds", NextIndexOutOfBounds, 4);
	TestEqual("Array_PreviousIndex should return the first index when out of bounds", PreviousIndexOutOfBounds, 0);

	TestEqual("Array_NextIndex should clamp a negative input index to 0 (no loop)",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, -2, false), 0);
	TestEqual("Array_NextIndex should clamp a negative input index to 0 (loop)",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, -2, true), 0);
	TestEqual("Array_NextIndex should wrap a large input index to 0 when looping",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, 10, true), 0);
	TestEqual("Array_NextIndex should clamp a large input index to the last index when not looping",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, 10, false), 4);
	TestEqual("Array_PreviousIndex should clamp a large input index to the last index (no loop)",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, 10, false), 4);
	TestEqual("Array_PreviousIndex should clamp a large input index to the last index (loop)",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, 10, true), 4);
	TestEqual("Array_PreviousIndex should wrap a negative input index to the last index when looping",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, -1, true), 4);
	TestEqual("Array_NextIndex should handle the maximum integer index",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_NextIndex(&TestObject->TestArray, ArrayProperty, MAX_int32, false), 4);
	TestEqual("Array_PreviousIndex should handle the minimum integer index",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_PreviousIndex(&TestObject->TestArray, ArrayProperty, MIN_int32, false), 0);

	TestObject->TestArray = {1, 2, 3, 4, 5};

	int32 FirstItem = -1;
	const bool bGotFirst = UDirectiveUtilArrayFunctionLibrary::GenericArray_GetFirstItem(&TestObject->TestArray, ArrayProperty, &FirstItem);
	TestTrue("GetFirstItem should succeed on a non-empty array", bGotFirst);
	TestEqual("GetFirstItem should return the first element", FirstItem, 1);

	int32 LastItem = -1;
	const bool bGotLast = UDirectiveUtilArrayFunctionLibrary::GenericArray_GetLastItem(&TestObject->TestArray, ArrayProperty, &LastItem);
	TestTrue("GetLastItem should succeed on a non-empty array", bGotLast);
	TestEqual("GetLastItem should return the last element", LastItem, 5);

	int32 IndexItem = -1;
	const bool bGotIndex = UDirectiveUtilArrayFunctionLibrary::GenericArray_GetItemAtIndex(&TestObject->TestArray, ArrayProperty, 2, &IndexItem);
	TestTrue("GetItemAtIndex should succeed for a valid index", bGotIndex);
	TestEqual("GetItemAtIndex should return the element at the index", IndexItem, 3);

	int32 OutOfRangeItem = 777;
	const bool bGotOutOfRange = UDirectiveUtilArrayFunctionLibrary::GenericArray_GetItemAtIndex(&TestObject->TestArray, ArrayProperty, 10, &OutOfRangeItem);
	TestFalse("GetItemAtIndex should fail for an out-of-range index", bGotOutOfRange);
	TestEqual("GetItemAtIndex should reset the output to default on failure", OutOfRangeItem, 0);

	int32 RandomItem = -1;
	int32 RandomIndex = -1;
	const bool bGotRandom = UDirectiveUtilArrayFunctionLibrary::GenericArray_GetRandomItem(&TestObject->TestArray, ArrayProperty, &RandomItem, &RandomIndex);
	TestTrue("GetRandomItem should succeed on a non-empty array", bGotRandom);
	TestTrue("GetRandomItem should return a valid index", TestObject->TestArray.IsValidIndex(RandomIndex));
	if (TestObject->TestArray.IsValidIndex(RandomIndex))
	{
		TestEqual("GetRandomItem item should match the element at the returned index", RandomItem, TestObject->TestArray[RandomIndex]);
	}

	TestObject->TestArray.Empty();

	int32 EmptyItem = 999;
	TestFalse("GetFirstItem should fail on an empty array", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetFirstItem(&TestObject->TestArray, ArrayProperty, &EmptyItem));
	TestEqual("GetFirstItem should reset the output to default on an empty array", EmptyItem, 0);

	EmptyItem = 999;
	TestFalse("GetLastItem should fail on an empty array", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetLastItem(&TestObject->TestArray, ArrayProperty, &EmptyItem));
	TestEqual("GetLastItem should reset the output to default on an empty array", EmptyItem, 0);

	int32 EmptyRandomItem = 999;
	int32 EmptyRandomIndex = 5;
	TestFalse("GetRandomItem should fail on an empty array", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetRandomItem(&TestObject->TestArray, ArrayProperty, &EmptyRandomItem, &EmptyRandomIndex));
	TestEqual("GetRandomItem should return INDEX_NONE on an empty array", EmptyRandomIndex, static_cast<int32>(INDEX_NONE));
	TestEqual("GetRandomItem should reset the output to default on an empty array", EmptyRandomItem, 0);

	TestObject->TestArray = {1, 2, 3};
	int32 PoppedItem = -1;
	const bool bPopped = UDirectiveUtilArrayFunctionLibrary::GenericArray_Pop(&TestObject->TestArray, ArrayProperty, &PoppedItem);
	TestTrue("Pop should succeed on a non-empty array", bPopped);
	TestEqual("Pop should return the last element", PoppedItem, 3);
	TestEqual("Pop should shrink the array by one", TestObject->TestArray.Num(), 2);
	TestEqual("Pop should leave the new last element intact", TestObject->TestArray.Last(), 2);

	TestObject->TestArray = {1, 2, 3};
	int32 PoppedFirst = -1;
	const bool bPoppedFirst = UDirectiveUtilArrayFunctionLibrary::GenericArray_PopFirst(&TestObject->TestArray, ArrayProperty, &PoppedFirst);
	TestTrue("PopFirst should succeed on a non-empty array", bPoppedFirst);
	TestEqual("PopFirst should return the first element", PoppedFirst, 1);
	TestEqual("PopFirst should shrink the array by one", TestObject->TestArray.Num(), 2);
	TestEqual("PopFirst should shift the remaining elements down", TestObject->TestArray[0], 2);

	TestObject->TestArray.Empty();
	int32 PoppedEmpty = 888;
	TestFalse("Pop should fail on an empty array", UDirectiveUtilArrayFunctionLibrary::GenericArray_Pop(&TestObject->TestArray, ArrayProperty, &PoppedEmpty));
	TestEqual("Pop should reset the output to default on an empty array", PoppedEmpty, 0);
	TestFalse("PopFirst should fail on an empty array", UDirectiveUtilArrayFunctionLibrary::GenericArray_PopFirst(&TestObject->TestArray, ArrayProperty, &PoppedEmpty));

	TestObject->TestArray = {10, 20, 30, 40};
	const bool bRemoved = UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtSwap(&TestObject->TestArray, ArrayProperty, 1);
	TestTrue("RemoveAtSwap should succeed for a valid index", bRemoved);
	TestEqual("RemoveAtSwap should shrink the array by one", TestObject->TestArray.Num(), 3);
	TestFalse("RemoveAtSwap should have removed the target element", TestObject->TestArray.Contains(20));
	TestEqual("RemoveAtSwap should move the previously-last element into the removed slot", TestObject->TestArray[1], 40);

	const bool bRemovedOutOfRange = UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtSwap(&TestObject->TestArray, ArrayProperty, 99);
	TestFalse("RemoveAtSwap should fail for an out-of-range index", bRemovedOutOfRange);
	TestEqual("RemoveAtSwap should not change the array on failure", TestObject->TestArray.Num(), 3);

	TestObject->TestArray = {10, 20, 30};
	const bool bRemovedLast = UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtSwap(&TestObject->TestArray, ArrayProperty, 2);
	TestTrue("RemoveAtSwap should succeed when removing the last element", bRemovedLast);
	TestEqual("RemoveAtSwap on the last element should shrink the array", TestObject->TestArray.Num(), 2);
	TestEqual("RemoveAtSwap on the last element should preserve the order of the rest", TestObject->TestArray[1], 20);

	int32 ItemToRemove = 2;
	TestObject->TestArray = {1, 2, 3, 2, 4, 2};
	TestTrue(
		"RemoveAllOccurrences should report matching values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(&TestObject->TestArray, ArrayProperty, &ItemToRemove));
	TestEqual(
		"RemoveAllOccurrences should remove every match and preserve survivor order",
		TestObject->TestArray,
		TArray<int32>({1, 3, 4}));

	ItemToRemove = 9;
	const TArray<int32> UnchangedValues = TestObject->TestArray;
	TestFalse(
		"RemoveAllOccurrences should report an absent value",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(&TestObject->TestArray, ArrayProperty, &ItemToRemove));
	TestEqual("RemoveAllOccurrences should not change an array without matches", TestObject->TestArray, UnchangedValues);

	TestObject->TestArray.Empty();
	TestFalse(
		"RemoveAllOccurrences should report false for an empty array",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(&TestObject->TestArray, ArrayProperty, &ItemToRemove));

	ItemToRemove = 5;
	TestObject->TestArray = {5, 5, 5};
	TestTrue(
		"RemoveAllOccurrences should remove an all-matching array",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(&TestObject->TestArray, ArrayProperty, &ItemToRemove));
	TestTrue("RemoveAllOccurrences should leave an all-matching array empty", TestObject->TestArray.IsEmpty());

	TestObject->TestArray = {0, 1, 2, 3, 4, 5, 6};
	TestEqual(
		"RemoveAtIndices should remove each valid index once",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtIndices(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<int32>({5, 1, 5, -1, 99, 3})),
		3);
	TestEqual(
		"RemoveAtIndices should preserve survivor order",
		TestObject->TestArray,
		TArray<int32>({0, 2, 4, 6}));

	const TArray<int32> BeforeInvalidIndices = TestObject->TestArray;
	TestEqual(
		"RemoveAtIndices should report zero for invalid indices",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtIndices(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<int32>({-5, 10, 10})),
		0);
	TestEqual(
		"RemoveAtIndices should not modify the target when no indices are valid",
		TestObject->TestArray,
		BeforeInvalidIndices);

	TestObject->TestArray = {10, 20, 30};
	TestEqual(
		"RemoveAtIndices should remove the full array",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtIndices(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<int32>({2, 0, 1, 1})),
		3);
	TestTrue("RemoveAtIndices should leave the array empty when every index is removed", TestObject->TestArray.IsEmpty());

	TestObject->TestArray = {0, 2, 4};
	TestEqual(
		"RemoveAtIndices should support using the target array as the index array",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtIndices(
			&TestObject->TestArray,
			ArrayProperty,
			TestObject->TestArray),
		2);
	TestEqual(
		"RemoveAtIndices should read aliased indices before modifying the target",
		TestObject->TestArray,
		TArray<int32>({2}));

	TestTrue("Integer arrays should use the bulk append path", ArrayProperty->Inner->HasAnyPropertyFlags(CPF_IsPlainOldData));
	const TArray<int32> IntegerAppendSource = {3, 4, 5};
	TestObject->TestArray = {1, 2};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestArray,
		ArrayProperty,
		&IntegerAppendSource,
		ArrayProperty);
	TestEqual(
		"AppendOptimized should append POD values in order",
		TestObject->TestArray,
		TArray<int32>({1, 2, 3, 4, 5}));
	TestEqual(
		"AppendOptimized should not modify the source array",
		IntegerAppendSource,
		TArray<int32>({3, 4, 5}));

	TestObject->TestArray.Empty();
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestArray,
		ArrayProperty,
		&IntegerAppendSource,
		ArrayProperty);
	TestEqual(
		"AppendOptimized should append into an empty target array",
		TestObject->TestArray,
		IntegerAppendSource);

	const TArray<int32> EmptyAppendSource;
	const TArray<int32> BeforeEmptyAppend = TestObject->TestArray;
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestArray,
		ArrayProperty,
		&EmptyAppendSource,
		ArrayProperty);
	TestEqual("AppendOptimized should ignore an empty source array", TestObject->TestArray, BeforeEmptyAppend);

	TestObject->TestArray = {7, 8, 9};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestArray,
		ArrayProperty,
		&TestObject->TestArray,
		ArrayProperty);
	TestEqual(
		"AppendOptimized should support appending an array to itself",
		TestObject->TestArray,
		TArray<int32>({7, 8, 9, 7, 8, 9}));

	const TArray<int32> IntegerInsertSource = {7, 8};
	TestObject->TestArray = {1, 2, 3};
	TestTrue(
		"InsertOptimized should insert POD values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestArray,
			ArrayProperty,
			&IntegerInsertSource,
			ArrayProperty,
			1));
	TestEqual(
		"InsertOptimized should preserve target and source order",
		TestObject->TestArray,
		TArray<int32>({1, 7, 8, 2, 3}));
	TestEqual(
		"InsertOptimized should not modify the source array",
		IntegerInsertSource,
		TArray<int32>({7, 8}));

	TestObject->TestArray = {1, 2, 3};
	TestTrue(
		"InsertOptimized should insert at the front",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestArray,
			ArrayProperty,
			&IntegerInsertSource,
			ArrayProperty,
			0));
	TestEqual(
		"InsertOptimized should preserve order at the front",
		TestObject->TestArray,
		TArray<int32>({7, 8, 1, 2, 3}));

	TestObject->TestArray = {1, 2, 3};
	TestTrue(
		"InsertOptimized should insert at the end",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestArray,
			ArrayProperty,
			&IntegerInsertSource,
			ArrayProperty,
			TestObject->TestArray.Num()));
	TestEqual(
		"InsertOptimized should preserve order at the end",
		TestObject->TestArray,
		TArray<int32>({1, 2, 3, 7, 8}));

	const TArray<int32> EmptyInsertSource;
	const TArray<int32> BeforeEmptyInsert = TestObject->TestArray;
	TestFalse(
		"InsertOptimized should report an empty source",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestArray,
			ArrayProperty,
			&EmptyInsertSource,
			ArrayProperty,
			1));
	TestEqual("InsertOptimized should ignore an empty source", TestObject->TestArray, BeforeEmptyInsert);

	TestFalse(
		"InsertOptimized should reject a negative index",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestArray,
			ArrayProperty,
			&IntegerInsertSource,
			ArrayProperty,
			-1));
	TestEqual("InsertOptimized should not modify the target for a negative index", TestObject->TestArray, BeforeEmptyInsert);

	TestFalse(
		"InsertOptimized should reject an index beyond the array end",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestArray,
			ArrayProperty,
			&IntegerInsertSource,
			ArrayProperty,
			TestObject->TestArray.Num() + 1));
	TestEqual("InsertOptimized should not modify the target for a large index", TestObject->TestArray, BeforeEmptyInsert);

	TestObject->TestArray = {4, 5, 6};
	TestTrue(
		"InsertOptimized should support inserting an array into itself",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestArray,
			ArrayProperty,
			&TestObject->TestArray,
			ArrayProperty,
			1));
	TestEqual(
		"InsertOptimized should preserve self-inserted values",
		TestObject->TestArray,
		TArray<int32>({4, 4, 5, 6, 5, 6}));

	TestObject->TestArray = {1, 2, 2, 3, 1, 4};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveDuplicates(&TestObject->TestArray, ArrayProperty);
	TestEqual("RemoveDuplicates should remove all duplicate entries", TestObject->TestArray.Num(), 4);
	if (TestObject->TestArray.Num() == 4)
	{
		TestEqual("RemoveDuplicates should keep the first occurrence (index 0)", TestObject->TestArray[0], 1);
		TestEqual("RemoveDuplicates should keep the first occurrence (index 1)", TestObject->TestArray[1], 2);
		TestEqual("RemoveDuplicates should keep the first occurrence (index 2)", TestObject->TestArray[2], 3);
		TestEqual("RemoveDuplicates should keep the first occurrence (index 3)", TestObject->TestArray[3], 4);
	}

	TestObject->TestArray = {5, 5, 5};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveDuplicates(&TestObject->TestArray, ArrayProperty);
	TestEqual("RemoveDuplicates should collapse an all-duplicates array to one element", TestObject->TestArray.Num(), 1);
	if (TestObject->TestArray.Num() == 1)
	{
		TestEqual("RemoveDuplicates should keep the single remaining value", TestObject->TestArray[0], 5);
	}

	TestObject->TestArray.Empty();
	UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveDuplicates(&TestObject->TestArray, ArrayProperty);
	TestEqual("RemoveDuplicates on an empty array should leave it empty", TestObject->TestArray.Num(), 0);

	TestObject->TestArray = {10, 20, 30, 40, 50};
	TArray<int32> SliceOut;
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(&TestObject->TestArray, ArrayProperty, 1, 3, &SliceOut, ArrayProperty);
	TestEqual("Slice should copy a contiguous range", SliceOut, TArray<int32>({20, 30, 40}));
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(&TestObject->TestArray, ArrayProperty, 3, 99, &SliceOut, ArrayProperty);
	TestEqual("Slice should clamp Count to the available elements", SliceOut, TArray<int32>({40, 50}));
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(&TestObject->TestArray, ArrayProperty, -5, 2, &SliceOut, ArrayProperty);
	TestEqual("Slice should clamp a negative start index to 0", SliceOut, TArray<int32>({10, 20}));
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(&TestObject->TestArray, ArrayProperty, 0, 0, &SliceOut, ArrayProperty);
	TestEqual("Slice with Count 0 should be empty", SliceOut.Num(), 0);
	TestObject->TestArray = {10, 20, 30, 40};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(&TestObject->TestArray, ArrayProperty, 1, 2, &TestObject->TestArray, ArrayProperty);
	TestEqual("Slice should support using the source array as its output", TestObject->TestArray, TArray<int32>({20, 30}));

	TestObject->TestArray = {1, 2, 3, 4, 5};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Rotate(&TestObject->TestArray, ArrayProperty, 2);
	TestEqual("Rotate by +2 should rotate toward the end", TestObject->TestArray, TArray<int32>({4, 5, 1, 2, 3}));
	TestObject->TestArray = {1, 2, 3, 4, 5};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Rotate(&TestObject->TestArray, ArrayProperty, -1);
	TestEqual("Rotate by -1 should rotate toward the start", TestObject->TestArray, TArray<int32>({2, 3, 4, 5, 1}));
	TestObject->TestArray = {1, 2, 3};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Rotate(&TestObject->TestArray, ArrayProperty, 3);
	TestEqual("Rotate by Length should be a no-op", TestObject->TestArray, TArray<int32>({1, 2, 3}));

	TestObject->TestArray = {1, 2, 2, 3, 1, 4};
	TArray<int32> DistinctOut;
	UDirectiveUtilArrayFunctionLibrary::GenericArray_GetDistinct(&TestObject->TestArray, ArrayProperty, &DistinctOut, ArrayProperty);
	TestEqual("GetDistinct should keep first occurrences in order", DistinctOut, TArray<int32>({1, 2, 3, 4}));
	TestEqual("GetDistinct should not modify the source array", TestObject->TestArray.Num(), 6);
	TestObject->TestArray = {1, 2, 2, 3, 1};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_GetDistinct(&TestObject->TestArray, ArrayProperty, &TestObject->TestArray, ArrayProperty);
	TestEqual("GetDistinct should support using the source array as its output", TestObject->TestArray, TArray<int32>({1, 2, 3}));

	FArrayProperty* DistinctStringArrayProperty = FindFProperty<FArrayProperty>(UDirectiveUtilTestObject::StaticClass(), GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestStringArray));
	TestNotNull("TestStringArray property should be found", DistinctStringArrayProperty);
	if (DistinctStringArrayProperty)
	{
		TestObject->TestStringArray = {TEXT("Alpha"), TEXT("Beta"), TEXT("Beta")};
		UDirectiveUtilArrayFunctionLibrary::GenericArray_GetDistinct(
			&TestObject->TestStringArray,
			DistinctStringArrayProperty,
			&TestObject->TestStringArray,
			DistinctStringArrayProperty);
		TestEqual("GetDistinct should preserve in-place string values", TestObject->TestStringArray, TArray<FString>({TEXT("Alpha"), TEXT("Beta")}));
	}

	TestObject->TestArray = {5, 1, 5, 2, 5, 3};
	int32 ItemToCount = 5;
	TestEqual("CountOccurrences should count matches", UDirectiveUtilArrayFunctionLibrary::GenericArray_CountOccurrences(&TestObject->TestArray, ArrayProperty, &ItemToCount), 3);
	int32 MissingItem = 99;
	TestEqual("CountOccurrences should return 0 for an absent item", UDirectiveUtilArrayFunctionLibrary::GenericArray_CountOccurrences(&TestObject->TestArray, ArrayProperty, &MissingItem), 0);

	TestObject->TestArray = {7, 7, 8, 7, 9, 8};
	int32 MostCommonItem = -1;
	int32 MostCommonCount = -1;
	const bool bGotMostCommon = UDirectiveUtilArrayFunctionLibrary::GenericArray_GetMostCommon(&TestObject->TestArray, ArrayProperty, &MostCommonItem, &MostCommonCount);
	TestTrue("GetMostCommon should succeed on a non-empty array", bGotMostCommon);
	TestEqual("GetMostCommon should return the most frequent element", MostCommonItem, 7);
	TestEqual("GetMostCommon should return the occurrence count", MostCommonCount, 3);
	TestObject->TestArray.Empty();
	int32 EmptyMostItem = 5;
	int32 EmptyMostCount = 5;
	TestFalse("GetMostCommon should fail on an empty array", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetMostCommon(&TestObject->TestArray, ArrayProperty, &EmptyMostItem, &EmptyMostCount));
	TestEqual("GetMostCommon should reset the count on an empty array", EmptyMostCount, 0);

	const TArray<FName> MutatingFunctions = {
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_RemoveDuplicates),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_AppendOptimized),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_InsertOptimized),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_Pop),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_PopFirst),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_RemoveAtSwap),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_RemoveAtIndices),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_RemoveAllOccurrences),
		GET_FUNCTION_NAME_CHECKED(UDirectiveUtilArrayFunctionLibrary, Array_Rotate)
	};
	for (const FName FunctionName : MutatingFunctions)
	{
		const UFunction* Function = UDirectiveUtilArrayFunctionLibrary::StaticClass()->FindFunctionByName(FunctionName);
		const FArrayProperty* TargetArrayProperty = Function ? FindFProperty<FArrayProperty>(Function, TEXT("TargetArray")) : nullptr;
		TestNotNull(*FString::Printf(TEXT("%s should expose a TargetArray parameter"), *FunctionName.ToString()), TargetArrayProperty);
		if (TargetArrayProperty)
		{
			TestFalse(*FString::Printf(TEXT("%s should expose TargetArray as mutable"), *FunctionName.ToString()), TargetArrayProperty->HasAnyPropertyFlags(CPF_ConstParm));
		}
#if WITH_EDITOR
		if (Function)
		{
			TestFalse(
				*FString::Printf(TEXT("%s should not advertise inert Blueprint thread safety"), *FunctionName.ToString()),
				Function->HasMetaData(TEXT("BlueprintThreadSafe")));
		}
#endif
	}

	TArray<int32> ParallelResults;
	ParallelResults.SetNumZeroed(64);
	ParallelFor(ParallelResults.Num(), [&ParallelResults, ArrayProperty](const int32 TaskIndex)
	{
		const int32 RemovedValue = TaskIndex + 1000;
		TArray<int32> Values = {RemovedValue, 7, RemovedValue, 11};
		const TArray<int32> Appended = {13, RemovedValue};
		UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
			&Values, ArrayProperty, &Appended, ArrayProperty);
		const bool bRemoved = UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(
			&Values, ArrayProperty, &RemovedValue);
		ParallelResults[TaskIndex] = bRemoved && Values == TArray<int32>({7, 11, 13}) ? 1 : 0;
	});
	TestTrue("Independent array operations should remain correct on worker tasks", ParallelResults.Find(0) == INDEX_NONE);

	TestObject->TestArray = {10, 20, 30, 40, 50};
	TArray<int32> SampledValues;
	FRandomStream FirstStream(1337);
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 3, false, &FirstStream, &SampledValues, ArrayProperty);
	TestEqual("Sample without replacement should return the requested count", SampledValues.Num(), 3);
	TestEqual("Sample without replacement should contain unique values", TSet<int32>(SampledValues).Num(), 3);

	TArray<int32> RepeatedSample;
	FRandomStream SecondStream(1337);
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 3, false, &SecondStream, &RepeatedSample, ArrayProperty);
	TestEqual("Sample from stream should be deterministic", RepeatedSample, SampledValues);

	FRandomStream ClampedStream(42);
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 20, false, &ClampedStream, &SampledValues, ArrayProperty);
	TestEqual("Sample without replacement should clamp to the source length", SampledValues.Num(), TestObject->TestArray.Num());

	FRandomStream ReplacementStream(7);
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 20, true, &ReplacementStream, &SampledValues, ArrayProperty);
	TestEqual("Sample with replacement should return the requested count", SampledValues.Num(), 20);

	TestObject->TestArray = {99};
	FRandomStream SingleValueStream(7);
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 4, true, &SingleValueStream, &SampledValues, ArrayProperty);
	TestEqual("Sample with replacement should repeat the only available value", SampledValues, TArray<int32>({99, 99, 99, 99}));

	TestObject->TestArray.Empty();
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 4, false, nullptr, &SampledValues, ArrayProperty);
	TestTrue("Sampling an empty array should return an empty array", SampledValues.IsEmpty());

	TestObject->TestArray = {10, 20, 30, 40, 50};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 0, false, nullptr, &SampledValues, ArrayProperty);
	TestTrue("Sampling zero values should return an empty array", SampledValues.IsEmpty());
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 1'000'001, true, nullptr, &SampledValues, ArrayProperty);
	TestTrue("Sampling should reject an unsafe output count", SampledValues.IsEmpty());

	const TArray<float> DeterministicWeights = {1.0f, 2.0f, 3.0f, 4.0f, 5.0f};
	TArray<int32> WeightedSample;
	TArray<int32> RepeatedWeightedSample;
	FRandomStream FirstWeightedStream(90210);
	FRandomStream SecondWeightedStream(90210);
	TestTrue(
		"Weighted sampling should accept matching inputs",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			DeterministicWeights,
			4,
			true,
			&FirstWeightedStream,
			&WeightedSample,
			ArrayProperty));
	TestTrue(
		"Weighted sampling from a stream should accept matching inputs",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			DeterministicWeights,
			4,
			true,
			&SecondWeightedStream,
			&RepeatedWeightedSample,
			ArrayProperty));
	TestEqual("Weighted sampling from a stream should be deterministic", RepeatedWeightedSample, WeightedSample);
	TestFalse(
		"Weighted sampling should reject an unsafe output count",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			DeterministicWeights,
			1'000'001,
			true,
			nullptr,
			&WeightedSample,
			ArrayProperty));
	TestTrue("Rejected weighted sampling should clear the output", WeightedSample.IsEmpty());

	FRandomStream FirstUniqueWeightedStream(31415);
	FRandomStream SecondUniqueWeightedStream(31415);
	TestTrue(
		"Weighted sampling without replacement should accept matching inputs",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			DeterministicWeights,
			5,
			false,
			&FirstUniqueWeightedStream,
			&WeightedSample,
			ArrayProperty));
	TestTrue(
		"Repeated weighted sampling without replacement should accept matching inputs",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			DeterministicWeights,
			5,
			false,
			&SecondUniqueWeightedStream,
			&RepeatedWeightedSample,
			ArrayProperty));
	TestEqual("Weighted sampling without replacement should be deterministic", RepeatedWeightedSample, WeightedSample);
	TestEqual("Weighted sampling without replacement should select each available value once", TSet<int32>(WeightedSample).Num(), 5);

	FRandomStream UnchangedWeightedStream(8675309);
	const int32 InitialWeightedSeed = UnchangedWeightedStream.GetCurrentSeed();
	TestTrue(
		"A zero weighted sample should succeed",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			DeterministicWeights,
			0,
			false,
			&UnchangedWeightedStream,
			&WeightedSample,
			ArrayProperty));
	TestEqual("A zero weighted sample should not advance its random stream", UnchangedWeightedStream.GetCurrentSeed(), InitialWeightedSeed);

	TestObject->TestArray = {0, 1};
	FRandomStream DistributionStream(1187);
	TestTrue(
		"Weighted sampling should accept proportional weights",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>({1.0f, 9.0f}),
			10000,
			true,
			&DistributionStream,
			&WeightedSample,
			ArrayProperty));
	int32 HeavySelectionCount = 0;
	for (const int32 Value : WeightedSample)
	{
		HeavySelectionCount += Value == 1 ? 1 : 0;
	}
	TestTrue("Weighted sampling should follow the supplied proportions", HeavySelectionCount > 8500 && HeavySelectionCount < 9500);

	TestObject->TestArray = {10, 20, 30, 40, 50};
	const TArray<float> SparseWeights = {
		0.0f,
		1.0f,
		-1.0f,
		std::numeric_limits<float>::quiet_NaN(),
		std::numeric_limits<float>::infinity()
	};
	FRandomStream SparseStream(17);
	TestTrue(
		"Weighted sampling should ignore non-positive and non-finite weights",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			SparseWeights,
			8,
			true,
			&SparseStream,
			&WeightedSample,
			ArrayProperty));
	TestEqual("Weighted sampling should select the only positive-weight value", WeightedSample, TArray<int32>({20, 20, 20, 20, 20, 20, 20, 20}));

	const TArray<float> TwoPositiveWeights = {1.0f, 0.0f, 2.0f, 0.0f, 0.0f};
	FRandomStream UniqueWeightedStream(44);
	TestTrue(
		"Weighted sampling without replacement should succeed",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TwoPositiveWeights,
			8,
			false,
			&UniqueWeightedStream,
			&WeightedSample,
			ArrayProperty));
	TestEqual("Weighted sampling without replacement should clamp to positive-weight entries", WeightedSample.Num(), 2);
	TestEqual("Weighted sampling without replacement should not repeat source indices", TSet<int32>(WeightedSample).Num(), 2);
	TestTrue("Weighted sampling without replacement should include the first weighted value", WeightedSample.Contains(10));
	TestTrue("Weighted sampling without replacement should include the second weighted value", WeightedSample.Contains(30));

	WeightedSample = {999};
	TestFalse(
		"Weighted sampling should reject a mismatched weights array",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>({1.0f}),
			1,
			false,
			nullptr,
			&WeightedSample,
			ArrayProperty));
	TestTrue("Weighted sampling should clear output after a weights mismatch", WeightedSample.IsEmpty());

	TestFalse(
		"Weighted sampling should reject a negative count",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TwoPositiveWeights,
			-1,
			false,
			nullptr,
			&WeightedSample,
			ArrayProperty));
	TestTrue("Weighted sampling should clear output after a negative count", WeightedSample.IsEmpty());

	TestTrue(
		"Weighted sampling should accept a zero count",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TwoPositiveWeights,
			0,
			false,
			nullptr,
			&WeightedSample,
			ArrayProperty));
	TestTrue("Weighted sampling should return an empty zero-count result", WeightedSample.IsEmpty());

	const TArray<float> EmptyWeights = {0.0f, 0.0f, 0.0f, 0.0f, 0.0f};
	TestFalse(
		"Weighted sampling should reject a positive count when all weights are zero",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			EmptyWeights,
			1,
			false,
			nullptr,
			&WeightedSample,
			ArrayProperty));
	TestTrue("Weighted sampling should clear output when no selectable entries exist", WeightedSample.IsEmpty());

	TestObject->TestArray.Empty();
	TestTrue(
		"Weighted sampling should accept an empty source for a zero count",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>(),
			0,
			false,
			nullptr,
			&WeightedSample,
			ArrayProperty));
	TestFalse(
		"Weighted sampling should reject a positive count for an empty source",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>(),
			1,
			false,
			nullptr,
			&WeightedSample,
			ArrayProperty));
	TestTrue("A failed empty weighted sample should leave an empty output", WeightedSample.IsEmpty());

	TestObject->TestArray = {10, 20, 30, 40};
	FRandomStream LeadingZeroStream(101);
	TestTrue(
		"Weighted sampling should handle leading zero weights",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>({0.0f, 0.0f, 0.0f, 1.0f}),
			4,
			true,
			&LeadingZeroStream,
			&WeightedSample,
			ArrayProperty));
	TestEqual("Leading zero weights should not select an unavailable value", WeightedSample, TArray<int32>({40, 40, 40, 40}));

	FRandomStream ExtremeWeightStream(2026);
	TestTrue(
		"Weighted sampling should handle maximum finite weights",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>({std::numeric_limits<float>::max(), std::numeric_limits<float>::max(), 0.0f, 0.0f}),
			2,
			false,
			&ExtremeWeightStream,
			&WeightedSample,
			ArrayProperty));
	TestEqual("Maximum finite weights should return both selectable values", WeightedSample.Num(), 2);
	TestTrue("Maximum finite weights should include the first value", WeightedSample.Contains(10));
	TestTrue("Maximum finite weights should include the second value", WeightedSample.Contains(20));

	TestObject->TestArray = {10, 20, 30};
	FRandomStream MixedRangeWeightStream(2027);
	TestTrue(
		"Weighted sampling should handle mixed finite weight ranges",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>({std::numeric_limits<float>::max(), 1.0f, 2.0f}),
			3,
			false,
			&MixedRangeWeightStream,
			&WeightedSample,
			ArrayProperty));
	TestEqual("Mixed finite weights should return every selectable value", WeightedSample.Num(), 3);
	TestEqual("Mixed finite weights should not repeat values", TSet<int32>(WeightedSample).Num(), 3);
	TestTrue("Mixed finite weights should include the first value", WeightedSample.Contains(10));
	TestTrue("Mixed finite weights should include the second value", WeightedSample.Contains(20));
	TestTrue("Mixed finite weights should include the third value", WeightedSample.Contains(30));

	TestObject->TestArray = {1, 2, 3, 4};
	FRandomStream AliasedWeightedStream(81);
	TestTrue(
		"Weighted sampling should support the source array as output",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>({1.0f, 1.0f, 1.0f, 1.0f}),
			2,
			false,
			&AliasedWeightedStream,
			&TestObject->TestArray,
			ArrayProperty));
	TestEqual("Aliased weighted sampling should return the requested count", TestObject->TestArray.Num(), 2);

	TestObject->TestArray = {10, 20, 30, 40, 50};
	TArray<int32> Page;
	int32 PageCount = 0;
	TestTrue("GetPage should return an available page", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetPage(&TestObject->TestArray, ArrayProperty, 1, 2, &Page, ArrayProperty, &PageCount));
	TestEqual("GetPage should return the second page", Page, TArray<int32>({30, 40}));
	TestEqual("GetPage should return the total page count", PageCount, 3);
	TestFalse("GetPage should reject a negative page", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetPage(&TestObject->TestArray, ArrayProperty, -1, 2, &Page, ArrayProperty, &PageCount));
	TestTrue("GetPage should clear output for a negative page", Page.IsEmpty());
	TestFalse("GetPage should reject a non-positive page size", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetPage(&TestObject->TestArray, ArrayProperty, 0, 0, &Page, ArrayProperty, &PageCount));
	TestEqual("GetPage should report zero pages for an invalid page size", PageCount, 0);

	TestObject->TestArray = {1, 2, 3, 4};
	FRandomStream InPlaceStream(11);
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(&TestObject->TestArray, ArrayProperty, 2, false, &InPlaceStream, &TestObject->TestArray, ArrayProperty);
	TestEqual("Sample should support the same source and output array", TestObject->TestArray.Num(), 2);
	TestObject->TestArray = {1, 2, 3, 4};
	TestTrue("GetPage should support the same source and output array", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetPage(&TestObject->TestArray, ArrayProperty, 1, 2, &TestObject->TestArray, ArrayProperty, &PageCount));
	TestEqual("In-place GetPage should return the requested values", TestObject->TestArray, TArray<int32>({3, 4}));

	TArray<FString> NaturalStrings = {TEXT("Item10"), TEXT("Item2"), TEXT("Item1"), TEXT("アイテム2")};
	UDirectiveUtilArrayFunctionLibrary::NaturalSortStringArray(NaturalStrings);
	TestEqual("Natural string sort should compare embedded numbers", NaturalStrings[0], FString(TEXT("Item1")));
	TestEqual("Natural string sort should place Item2 before Item10", NaturalStrings[1], FString(TEXT("Item2")));
	TestEqual("Natural string sort should place Item10 after Item2", NaturalStrings[2], FString(TEXT("Item10")));
	TestEqual("Natural string sort should preserve Unicode strings", NaturalStrings[3], FString(TEXT("アイテム2")));
	UDirectiveUtilArrayFunctionLibrary::NaturalSortStringArray(NaturalStrings, true);
	TestEqual("Natural string sort should support descending order", NaturalStrings.Last(), FString(TEXT("Item1")));

	TArray<FName> NaturalNames = {FName(TEXT("Actor12")), FName(TEXT("Actor3")), FName(TEXT("Actor1"))};
	UDirectiveUtilArrayFunctionLibrary::NaturalSortNameArray(NaturalNames);
	TestEqual("Natural name sort should compare embedded numbers", NaturalNames, TArray<FName>({FName(TEXT("Actor1")), FName(TEXT("Actor3")), FName(TEXT("Actor12"))}));

	TestObject->TestArray = {1, 2, 3, 4, 5};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(&TestObject->TestArray, ArrayProperty, 1, 3, &TestObject->TestArray, ArrayProperty);
	TestEqual("Slice should support the same source and output array", TestObject->TestArray, TArray<int32>({2, 3, 4}));

	TestObject->TestArray = {3, 1, 3, 2, 1};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_GetDistinct(&TestObject->TestArray, ArrayProperty, &TestObject->TestArray, ArrayProperty);
	TestEqual("GetDistinct should support the same source and output array", TestObject->TestArray, TArray<int32>({3, 1, 2}));

	FArrayProperty* StringArrayProperty = FindFProperty<FArrayProperty>(
		UDirectiveUtilTestObject::StaticClass(),
		GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestStringArray));
	FArrayProperty* TextArrayProperty = FindFProperty<FArrayProperty>(
		UDirectiveUtilTestObject::StaticClass(),
		GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestTextArray));
	FArrayProperty* BoolArrayProperty = FindFProperty<FArrayProperty>(
		UDirectiveUtilTestObject::StaticClass(),
		GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestBoolArray));
	FArrayProperty* CollisionArrayProperty = FindFProperty<FArrayProperty>(
		UDirectiveUtilTestObject::StaticClass(),
		GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestCollisionArray));
	FArrayProperty* PodArrayProperty = FindFProperty<FArrayProperty>(
		UDirectiveUtilTestObject::StaticClass(),
		GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestPodArray));
	FArrayProperty* ObjectArrayProperty = FindFProperty<FArrayProperty>(
		UDirectiveUtilTestObject::StaticClass(),
		GET_MEMBER_NAME_CHECKED(UDirectiveUtilTestObject, TestObjectArray));
	TestNotNull("String array property should be available", StringArrayProperty);
	TestNotNull("Text array property should be available", TextArrayProperty);
	TestNotNull("Boolean array property should be available", BoolArrayProperty);
	TestNotNull("Collision array property should be available", CollisionArrayProperty);
	TestNotNull("POD struct array property should be available", PodArrayProperty);
	TestNotNull("Object array property should be available", ObjectArrayProperty);

	TestFalse("String arrays should use the property-aware append path", StringArrayProperty->Inner->HasAnyPropertyFlags(CPF_IsPlainOldData));
	const TArray<FString> StringAppendSource = {TEXT("Three"), TEXT("Four")};
	TestObject->TestStringArray = {TEXT("One"), TEXT("Two")};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestStringArray,
		StringArrayProperty,
		&StringAppendSource,
		StringArrayProperty);
	TestEqual(
		"AppendOptimized should preserve non-trivial values",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("One"), TEXT("Two"), TEXT("Three"), TEXT("Four")}));

	TestObject->TestStringArray = {TEXT("Alpha"), TEXT("Beta")};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestStringArray,
		StringArrayProperty,
		&TestObject->TestStringArray,
		StringArrayProperty);
	TestEqual(
		"AppendOptimized should support self-appending non-trivial values",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("Alpha"), TEXT("Beta"), TEXT("Alpha"), TEXT("Beta")}));

	const TArray<FString> StringInsertSource = {TEXT("Two"), TEXT("Three")};
	TestObject->TestStringArray = {TEXT("One"), TEXT("Four")};
	TestTrue(
		"InsertOptimized should support non-trivial values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestStringArray,
			StringArrayProperty,
			&StringInsertSource,
			StringArrayProperty,
			1));
	TestEqual(
		"InsertOptimized should preserve non-trivial value order",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("One"), TEXT("Two"), TEXT("Three"), TEXT("Four")}));

	TestObject->TestStringArray = {TEXT("Alpha"), TEXT("Beta"), TEXT("Gamma")};
	TestTrue(
		"InsertOptimized should self-insert non-trivial values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestStringArray,
			StringArrayProperty,
			&TestObject->TestStringArray,
			StringArrayProperty,
			2));
	TestEqual(
		"InsertOptimized should preserve self-inserted non-trivial values",
		TestObject->TestStringArray,
		TArray<FString>({
			TEXT("Alpha"),
			TEXT("Beta"),
			TEXT("Alpha"),
			TEXT("Beta"),
			TEXT("Gamma"),
			TEXT("Gamma")
		}));

	TestObject->TestStringArray = {
		TEXT("Zero"),
		TEXT("One"),
		TEXT("Two"),
		TEXT("Three"),
		TEXT("Four")
	};
	TestEqual(
		"RemoveAtIndices should remove non-trivial values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtIndices(
			&TestObject->TestStringArray,
			StringArrayProperty,
			TArray<int32>({3, 1, 3})),
		2);
	TestEqual(
		"RemoveAtIndices should preserve non-trivial survivor order",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("Zero"), TEXT("Two"), TEXT("Four")}));

	const TArray<bool> BoolAppendSource = {false, true, false};
	TestObject->TestBoolArray = {true};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestBoolArray,
		BoolArrayProperty,
		&BoolAppendSource,
		BoolArrayProperty);
	TestEqual(
		"AppendOptimized should preserve Boolean values",
		TestObject->TestBoolArray,
		TArray<bool>({true, false, true, false}));

	TestObject->TestBoolArray = {true, false, false};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestBoolArray,
		BoolArrayProperty,
		&TestObject->TestBoolArray,
		BoolArrayProperty);
	TestEqual(
		"AppendOptimized should support self-appending Boolean values",
		TestObject->TestBoolArray,
		TArray<bool>({true, false, false, true, false, false}));

	auto MakePodValue = [](const int32 Index, const float Weight)
	{
		FDirectiveUtilPodValue Value;
		Value.Index = Index;
		Value.Weight = Weight;
		return Value;
	};
	TestTrue("POD struct arrays should use the bulk append path", PodArrayProperty->Inner->HasAnyPropertyFlags(CPF_IsPlainOldData));
	const TArray<FDirectiveUtilPodValue> PodAppendSource = {
		MakePodValue(2, 2.5f),
		MakePodValue(3, 3.5f)
	};
	TestObject->TestPodArray = {MakePodValue(1, 1.5f)};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestPodArray,
		PodArrayProperty,
		&PodAppendSource,
		PodArrayProperty);
	TestEqual("AppendOptimized should append POD structs", TestObject->TestPodArray.Num(), 3);
	for (int32 Index = 0; Index < TestObject->TestPodArray.Num(); ++Index)
	{
		TestEqual("AppendOptimized should preserve POD struct indices", TestObject->TestPodArray[Index].Index, Index + 1);
		TestEqual("AppendOptimized should preserve POD struct weights", TestObject->TestPodArray[Index].Weight, static_cast<float>(Index) + 1.5f);
	}
	TestEqual("AppendOptimized should not modify the POD struct source", PodAppendSource.Num(), 2);
	if (PodAppendSource.Num() == 2)
	{
		TestEqual("AppendOptimized should preserve the first POD source index", PodAppendSource[0].Index, 2);
		TestEqual("AppendOptimized should preserve the second POD source index", PodAppendSource[1].Index, 3);
	}

	TestObject->TestPodArray = {MakePodValue(4, 4.5f), MakePodValue(5, 5.5f)};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestPodArray,
		PodArrayProperty,
		&TestObject->TestPodArray,
		PodArrayProperty);
	TestEqual("AppendOptimized should self-append POD structs", TestObject->TestPodArray.Num(), 4);
	if (TestObject->TestPodArray.Num() == 4)
	{
		TestEqual("AppendOptimized should preserve the first self-appended POD struct", TestObject->TestPodArray[2].Index, 4);
		TestEqual("AppendOptimized should preserve the second self-appended POD struct", TestObject->TestPodArray[3].Index, 5);
	}

	TestFalse("POD struct grouping should use the reflected-value hash path", PodArrayProperty->Inner->HasAllPropertyFlags(CPF_HasGetValueTypeHash));
	TestObject->TestPodArray = {
		MakePodValue(1, 1.5f),
		MakePodValue(2, 2.5f),
		MakePodValue(1, 1.5f),
		MakePodValue(3, 3.5f),
		MakePodValue(1, 1.5f)
	};
	UDirectiveUtilTestObject* PodResultObject = NewObject<UDirectiveUtilTestObject>();
	UDirectiveUtilArrayFunctionLibrary::GenericArray_GetDistinct(
		&TestObject->TestPodArray,
		PodArrayProperty,
		&PodResultObject->TestPodArray,
		PodArrayProperty);
	TestEqual("GetDistinct should group unhashable POD structs", PodResultObject->TestPodArray.Num(), 3);
	if (PodResultObject->TestPodArray.Num() == 3)
	{
		TestEqual("GetDistinct should retain the first POD value", PodResultObject->TestPodArray[0].Index, 1);
		TestEqual("GetDistinct should retain the second POD value", PodResultObject->TestPodArray[1].Index, 2);
		TestEqual("GetDistinct should retain the third POD value", PodResultObject->TestPodArray[2].Index, 3);
	}
	FDirectiveUtilPodValue MostCommonPod = MakePodValue(INDEX_NONE, 0.0f);
	int32 MostCommonPodCount = 0;
	TestTrue(
		"GetMostCommon should group unhashable POD structs",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_GetMostCommon(
			&TestObject->TestPodArray,
			PodArrayProperty,
			&MostCommonPod,
			&MostCommonPodCount));
	TestEqual("GetMostCommon should return the repeated POD value", MostCommonPod.Index, 1);
	TestEqual("GetMostCommon should report the POD value count", MostCommonPodCount, 3);

	TestObject->TestStringArray = {TEXT("Zero"), TEXT("Selected"), TEXT("Never")};
	TArray<FString> WeightedStrings;
	FRandomStream WeightedStringStream(55);
	TestTrue(
		"Weighted sampling should preserve non-trivial array values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestStringArray,
			StringArrayProperty,
			TArray<float>({0.0f, 1.0f, 0.0f}),
			3,
			true,
			&WeightedStringStream,
			&WeightedStrings,
			StringArrayProperty));
	TestEqual(
		"Weighted sampling should copy the selected non-trivial value",
		WeightedStrings,
		TArray<FString>({TEXT("Selected"), TEXT("Selected"), TEXT("Selected")}));

	TestObject->TestStringArray = {TEXT("One"), TEXT("Two"), TEXT("Three"), TEXT("Four")};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Rotate(&TestObject->TestStringArray, StringArrayProperty, 2);
	TestEqual(
		"Rotate should preserve non-trivial values",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("Three"), TEXT("Four"), TEXT("One"), TEXT("Two")}));
	UDirectiveUtilArrayFunctionLibrary::GenericArray_Rotate(&TestObject->TestStringArray, StringArrayProperty, -2);
	TestEqual(
		"Rotate should support negative shifts for non-trivial values",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("One"), TEXT("Two"), TEXT("Three"), TEXT("Four")}));

	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(
		&TestObject->TestStringArray,
		StringArrayProperty,
		1,
		2,
		&TestObject->TestStringArray,
		StringArrayProperty);
	TestEqual("Aliased Slice should preserve string values", TestObject->TestStringArray, TArray<FString>({TEXT("Two"), TEXT("Three")}));

	TestObject->TestStringArray = {TEXT("Remove"), TEXT("Keep A"), TEXT("Remove"), TEXT("Keep B")};
	const FString StringToRemove = TEXT("Remove");
	TestTrue(
		"RemoveAllOccurrences should support strings",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(
			&TestObject->TestStringArray,
			StringArrayProperty,
			&StringToRemove));
	TestEqual(
		"RemoveAllOccurrences should preserve string survivor order",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("Keep A"), TEXT("Keep B")}));

	UObject* FirstObject = NewObject<UDirectiveUtilTestObject>(TestObject);
	UObject* SecondObject = NewObject<UDirectiveUtilTestObject>(TestObject);
	UObject* ThirdObject = NewObject<UDirectiveUtilTestObject>(TestObject);
	const TArray<TObjectPtr<UObject>> ObjectAppendSource = {SecondObject, ThirdObject};
	TestObject->TestObjectArray = {FirstObject};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestObjectArray,
		ObjectArrayProperty,
		&ObjectAppendSource,
		ObjectArrayProperty);
	TestEqual("AppendOptimized should preserve object references", TestObject->TestObjectArray.Num(), 3);
	if (TestObject->TestObjectArray.Num() == 3)
	{
		TestEqual("AppendOptimized should retain the target object", TestObject->TestObjectArray[0].Get(), FirstObject);
		TestEqual("AppendOptimized should append the first source object", TestObject->TestObjectArray[1].Get(), SecondObject);
		TestEqual("AppendOptimized should append the second source object", TestObject->TestObjectArray[2].Get(), ThirdObject);
	}

	TestObject->TestObjectArray = {FirstObject, SecondObject, FirstObject};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveDuplicates(&TestObject->TestObjectArray, ObjectArrayProperty);
	TestEqual("RemoveDuplicates should preserve object references", TestObject->TestObjectArray.Num(), 2);
	if (TestObject->TestObjectArray.Num() == 2)
	{
		TestEqual("RemoveDuplicates should retain the first object", TestObject->TestObjectArray[0].Get(), FirstObject);
		TestEqual("RemoveDuplicates should retain the second object", TestObject->TestObjectArray[1].Get(), SecondObject);
	}

	TestObject->TestObjectArray = {FirstObject, SecondObject, ThirdObject};
	TestTrue("Aliased object GetPage should succeed", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetPage(
		&TestObject->TestObjectArray,
		ObjectArrayProperty,
		1,
		2,
		&TestObject->TestObjectArray,
		ObjectArrayProperty,
		&PageCount));
	TestEqual("Aliased object GetPage should preserve the selected reference", TestObject->TestObjectArray.Num(), 1);
	if (TestObject->TestObjectArray.Num() == 1)
	{
		TestEqual("Aliased object GetPage should return the final object", TestObject->TestObjectArray[0].Get(), ThirdObject);
	}

	TestObject->TestObjectArray = {FirstObject, nullptr, SecondObject, FirstObject, nullptr};
	TestTrue(
		"RemoveAllOccurrences should support object references",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(
			&TestObject->TestObjectArray,
			ObjectArrayProperty,
			&FirstObject));
	TestEqual("RemoveAllOccurrences should retain object and null survivors", TestObject->TestObjectArray.Num(), 3);
	if (TestObject->TestObjectArray.Num() == 3)
	{
		TestNull("RemoveAllOccurrences should retain the first null", TestObject->TestObjectArray[0].Get());
		TestEqual("RemoveAllOccurrences should retain the unmatched object", TestObject->TestObjectArray[1].Get(), SecondObject);
		TestNull("RemoveAllOccurrences should retain the second null", TestObject->TestObjectArray[2].Get());
	}
	UObject* NullObject = nullptr;
	TestTrue(
		"RemoveAllOccurrences should remove null object references",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(
			&TestObject->TestObjectArray,
			ObjectArrayProperty,
			&NullObject));
	TestEqual("RemoveAllOccurrences should leave the non-null object", TestObject->TestObjectArray.Num(), 1);

	TestObject->TestObjectArray = {FirstObject, nullptr, SecondObject, ThirdObject};
	TestEqual(
		"RemoveAtIndices should preserve object references",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtIndices(
			&TestObject->TestObjectArray,
			ObjectArrayProperty,
			TArray<int32>({1, 3})),
		2);
	TestEqual("RemoveAtIndices should retain two object references", TestObject->TestObjectArray.Num(), 2);
	if (TestObject->TestObjectArray.Num() == 2)
	{
		TestEqual("RemoveAtIndices should retain the first object", TestObject->TestObjectArray[0].Get(), FirstObject);
		TestEqual("RemoveAtIndices should retain the second object", TestObject->TestObjectArray[1].Get(), SecondObject);
	}

	TestObject->TestStringArray = {TEXT("unchanged")};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_AppendOptimized(
		&TestObject->TestStringArray,
		StringArrayProperty,
		&TestObject->TestArray,
		ArrayProperty);
	TestEqual(
		"AppendOptimized should reject mismatched array types without changing the target",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("unchanged")}));

	TestFalse(
		"InsertOptimized should reject mismatched array types",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
			&TestObject->TestStringArray,
			StringArrayProperty,
			&TestObject->TestArray,
			ArrayProperty,
			0));
	TestEqual(
		"InsertOptimized should not change a target with a mismatched source type",
		TestObject->TestStringArray,
		TArray<FString>({TEXT("unchanged")}));

	UDirectiveUtilArrayFunctionLibrary::GenericArray_Slice(
		&TestObject->TestArray,
		ArrayProperty,
		0,
		1,
		&TestObject->TestStringArray,
		StringArrayProperty);
	TestEqual("Slice should reject mismatched array types without changing output", TestObject->TestStringArray, TArray<FString>({TEXT("unchanged")}));
	TestFalse(
		"Weighted sampling should reject mismatched output types",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_SampleWeighted(
			&TestObject->TestArray,
			ArrayProperty,
			TArray<float>({1.0f, 1.0f, 1.0f}),
			1,
			false,
			nullptr,
			&TestObject->TestStringArray,
			StringArrayProperty));
	TestEqual("Weighted sampling should leave a mismatched output unchanged", TestObject->TestStringArray, TArray<FString>({TEXT("unchanged")}));

	const FText AlphaText = FText::FromString(TEXT("Alpha"));
	const FText BetaText = FText::FromString(TEXT("Beta"));
	TestObject->TestTextArray = {AlphaText, BetaText, AlphaText};
	UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveDuplicates(&TestObject->TestTextArray, TextArrayProperty);
	TestEqual("RemoveDuplicates should support unhashable property types", TestObject->TestTextArray.Num(), 2);
	if (TestObject->TestTextArray.Num() == 2)
	{
		TestTrue("RemoveDuplicates should retain the first unhashable value", TestObject->TestTextArray[0].IdenticalTo(AlphaText));
		TestTrue("RemoveDuplicates should retain the second unhashable value", TestObject->TestTextArray[1].IdenticalTo(BetaText));
	}

	TestObject->TestTextArray = {AlphaText, BetaText, AlphaText, BetaText};
	TestTrue(
		"RemoveAllOccurrences should support text values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(
			&TestObject->TestTextArray,
			TextArrayProperty,
			&AlphaText));
	TestEqual("RemoveAllOccurrences should remove matching text values", TestObject->TestTextArray.Num(), 2);
	if (TestObject->TestTextArray.Num() == 2)
	{
		TestTrue("RemoveAllOccurrences should retain the first text survivor", TestObject->TestTextArray[0].IdenticalTo(BetaText));
		TestTrue("RemoveAllOccurrences should retain the second text survivor", TestObject->TestTextArray[1].IdenticalTo(BetaText));
	}

	TestObject->TestBoolArray = {true, false, true, false, true};
	const bool bBoolToRemove = true;
	TestTrue(
		"RemoveAllOccurrences should support Boolean values",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(
			&TestObject->TestBoolArray,
			BoolArrayProperty,
			&bBoolToRemove));
	TestEqual("RemoveAllOccurrences should remove matching Boolean values", TestObject->TestBoolArray, TArray<bool>({false, false}));

	auto AddCollisionValue = [&TestObject](const int32 Value)
	{
		FDirectiveUtilCollisionValue& Entry = TestObject->TestCollisionArray.AddDefaulted_GetRef();
		Entry.Value = Value;
	};
	TestObject->TestCollisionArray.Reset();
	for (const int32 Value : {1, 2, 1, 3, 2})
	{
		AddCollisionValue(Value);
	}
	TestTrue("Collision test property should expose a value hash", CollisionArrayProperty->Inner->HasAllPropertyFlags(CPF_HasGetValueTypeHash));
	UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveDuplicates(&TestObject->TestCollisionArray, CollisionArrayProperty);
	TestEqual("RemoveDuplicates should resolve hash collisions", TestObject->TestCollisionArray.Num(), 3);
	if (TestObject->TestCollisionArray.Num() == 3)
	{
		TestEqual("Hash collision result should retain the first value", TestObject->TestCollisionArray[0].Value, 1);
		TestEqual("Hash collision result should retain the second value", TestObject->TestCollisionArray[1].Value, 2);
		TestEqual("Hash collision result should retain the third value", TestObject->TestCollisionArray[2].Value, 3);
	}

	TestObject->TestCollisionArray.Reset();
	for (const int32 Value : {1, 2, 1, 3, 1, 4})
	{
		AddCollisionValue(Value);
	}
	FDirectiveUtilCollisionValue CollisionToRemove;
	CollisionToRemove.Value = 1;
	TestTrue(
		"RemoveAllOccurrences should support struct equality",
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAllOccurrences(
			&TestObject->TestCollisionArray,
			CollisionArrayProperty,
			&CollisionToRemove));
	TestEqual("RemoveAllOccurrences should keep struct survivors", TestObject->TestCollisionArray.Num(), 3);
	if (TestObject->TestCollisionArray.Num() == 3)
	{
		TestEqual("RemoveAllOccurrences should retain the first struct survivor", TestObject->TestCollisionArray[0].Value, 2);
		TestEqual("RemoveAllOccurrences should retain the second struct survivor", TestObject->TestCollisionArray[1].Value, 3);
		TestEqual("RemoveAllOccurrences should retain the third struct survivor", TestObject->TestCollisionArray[2].Value, 4);
	}

	TestObject->TestCollisionArray.Reset();
	for (const int32 Value : {4, 5, 5, 4})
	{
		AddCollisionValue(Value);
	}
	FDirectiveUtilCollisionValue MostCommonCollision;
	MostCommonCount = 0;
	TestTrue("GetMostCommon should resolve hash collisions", UDirectiveUtilArrayFunctionLibrary::GenericArray_GetMostCommon(
		&TestObject->TestCollisionArray,
		CollisionArrayProperty,
		&MostCommonCollision,
		&MostCommonCount));
	TestEqual("GetMostCommon should use first occurrence to break collision ties", MostCommonCollision.Value, 4);
	TestEqual("GetMostCommon should report the collision value count", MostCommonCount, 2);

	TestObject->TestArray.SetNumUninitialized(100);
	for (int32 Index = 0; Index < TestObject->TestArray.Num(); ++Index)
	{
		TestObject->TestArray[Index] = Index;
	}
	for (const int32 Count : {10, 75})
	{
		FRandomStream CompatibilityStream(9917);
		UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(
			&TestObject->TestArray,
			ArrayProperty,
			Count,
			false,
			&CompatibilityStream,
			&SampledValues,
			ArrayProperty);
		TestEqual(
			FString::Printf(TEXT("Sampling %d values should match dense Fisher-Yates"), Count),
			SampledValues,
			BuildReferenceSample(TestObject->TestArray.Num(), Count, 9917));
	}

	TArray<int32> SelectionCounts;
	SelectionCounts.Init(0, 5);
	TestObject->TestArray = {0, 1, 2, 3, 4};
	FRandomStream UniformityStream(77123);
	for (int32 Iteration = 0; Iteration < 5000; ++Iteration)
	{
		UDirectiveUtilArrayFunctionLibrary::GenericArray_Sample(
			&TestObject->TestArray,
			ArrayProperty,
			1,
			false,
			&UniformityStream,
			&SampledValues,
			ArrayProperty);
		if (SampledValues.Num() == 1 && SelectionCounts.IsValidIndex(SampledValues[0]))
		{
			++SelectionCounts[SampledValues[0]];
		}
	}
	for (int32 Value = 0; Value < SelectionCounts.Num(); ++Value)
	{
		TestTrue(
			FString::Printf(TEXT("Sampling frequency for value %d should remain within tolerance"), Value),
			FMath::Abs(SelectionCounts[Value] - 1000) <= 150);
	}

	FRandomStream FuzzStream(18181);
	for (int32 Iteration = 0; Iteration < 100; ++Iteration)
	{
		TArray<int32> SourceValues;
		const int32 ValueCount = FuzzStream.RandRange(0, 128);
		SourceValues.Reserve(ValueCount);
		for (int32 Index = 0; Index < ValueCount; ++Index)
		{
			SourceValues.Add(FuzzStream.RandRange(-12, 12));
		}
		const TArray<int32> ExpectedDistinct = BuildReferenceDistinct(SourceValues);
		TestObject->TestArray = SourceValues;
		UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveDuplicates(&TestObject->TestArray, ArrayProperty);
		TestEqual(FString::Printf(TEXT("RemoveDuplicates fuzz case %d"), Iteration), TestObject->TestArray, ExpectedDistinct);
		TestObject->TestArray = SourceValues;
		UDirectiveUtilArrayFunctionLibrary::GenericArray_GetDistinct(&TestObject->TestArray, ArrayProperty, &DistinctOut, ArrayProperty);
		TestEqual(FString::Printf(TEXT("GetDistinct fuzz case %d"), Iteration), DistinctOut, ExpectedDistinct);

		TArray<int32> InsertValues;
		const int32 InsertCount = FuzzStream.RandRange(0, 32);
		InsertValues.Reserve(InsertCount);
		for (int32 Index = 0; Index < InsertCount; ++Index)
		{
			InsertValues.Add(FuzzStream.RandRange(-20, 20));
		}
		const int32 InsertIndex = FuzzStream.RandRange(0, SourceValues.Num());
		TArray<int32> ExpectedInsert = SourceValues;
		ExpectedInsert.Insert(InsertValues, InsertIndex);
		TestObject->TestArray = SourceValues;
		TestEqual(
			FString::Printf(TEXT("InsertOptimized fuzz result %d"), Iteration),
			UDirectiveUtilArrayFunctionLibrary::GenericArray_InsertOptimized(
				&TestObject->TestArray,
				ArrayProperty,
				&InsertValues,
				ArrayProperty,
				InsertIndex),
			!InsertValues.IsEmpty());
		TestEqual(
			FString::Printf(TEXT("InsertOptimized fuzz values %d"), Iteration),
			TestObject->TestArray,
			ExpectedInsert);

		TArray<int32> RemovalIndices;
		const int32 RemovalCount = FuzzStream.RandRange(0, 48);
		RemovalIndices.Reserve(RemovalCount);
		for (int32 Index = 0; Index < RemovalCount; ++Index)
		{
			RemovalIndices.Add(FuzzStream.RandRange(-8, SourceValues.Num() + 8));
		}
		const TArray<int32> ExpectedRemoval = BuildReferenceRemoval(SourceValues, RemovalIndices);
		TestObject->TestArray = SourceValues;
		const int32 RemovedCount = UDirectiveUtilArrayFunctionLibrary::GenericArray_RemoveAtIndices(
			&TestObject->TestArray,
			ArrayProperty,
			RemovalIndices);
		TestEqual(
			FString::Printf(TEXT("RemoveAtIndices fuzz count %d"), Iteration),
			RemovedCount,
			SourceValues.Num() - ExpectedRemoval.Num());
		TestEqual(
			FString::Printf(TEXT("RemoveAtIndices fuzz values %d"), Iteration),
			TestObject->TestArray,
			ExpectedRemoval);
	}

	TArray<FString> StableNaturalStrings = {TEXT("ItemA"), TEXT("itema"), TEXT("ItemB"), TEXT("itemb")};
	UDirectiveUtilArrayFunctionLibrary::NaturalSortStringArray(StableNaturalStrings);
	TestEqual(
		"Natural string sort should preserve equivalent-key order",
		StableNaturalStrings,
		TArray<FString>({TEXT("ItemA"), TEXT("itema"), TEXT("ItemB"), TEXT("itemb")}));
	UDirectiveUtilArrayFunctionLibrary::NaturalSortStringArray(StableNaturalStrings, true);
	TestEqual(
		"Descending natural string sort should preserve equivalent-key order",
		StableNaturalStrings,
		TArray<FString>({TEXT("ItemB"), TEXT("itemb"), TEXT("ItemA"), TEXT("itema")}));

	return true;
}