diff --git a/tests/testEndGen.cpp b/tests/testEndGen.cpp
new file mode 100644
index 0000000..3f7e2f5
--- /dev/null
+++ b/tests/testEndGen.cpp
@@ -0,0 +1,156 @@
+#include "testHarness.h"
+#include "vf/EndGen.h"
+
+#include <cmath>
+#include <set>
+
+using namespace vf;
+
+namespace {
+
+float distanceFromOrigin(int gx, int gz) {
+    float x = static_cast<float>(gx);
+    float z = static_cast<float>(gz);
+    return std::sqrt(x * x + z * z);
+}
+
+bool locateOuterIsland(const EndGenerator& generator, int& outX, int& outZ) {
+    const EndGenerator::Params& params = generator.settings();
+    for (int gx = params.outerDistance; gx < params.outerDistance + 2000; gx += 4) {
+        for (int gz = -600; gz <= 600; gz += 4) {
+            if (generator.biomeAt(gx, gz) != EndBiome::OuterIsland) continue;
+            outX = gx;
+            outZ = gz;
+            return true;
+        }
+    }
+    return false;
+}
+
+int tallyBlocks(const World& world, Block block, int minX, int minZ, int span, int ceilingY) {
+    int total = 0;
+    for (int gx = minX; gx < minX + span; ++gx)
+        for (int gz = minZ; gz < minZ + span; ++gz)
+            for (int gy = 0; gy < ceilingY; ++gy)
+                if (world.blockAt(gx, gy, gz) == block) ++total;
+    return total;
+}
+
+} // namespace
+
+VF_TEST(endChunkGenerationRepeatsExactlyOnTheSameSeed) {
+    EndGenerator generator;
+    Chunk first, second;
+    generator.generateChunk(first, {1, 3, -1});
+    generator.generateChunk(second, {1, 3, -1});
+    CHECK(first.raw() == second.raw());
+
+    EndGenerator::Params other;
+    other.seed = 24601u;
+    EndGenerator reseeded(other);
+    Chunk different;
+    reseeded.generateChunk(different, {1, 3, -1});
+    CHECK(first.raw() != different.raw());
+}
+
+VF_TEST(endColumnIsByteIdenticalAcrossTwoRuns) {
+    EndGenerator generator;
+    World first, second;
+    generator.generateColumn(first, 2, -2);
+    generator.generateColumn(second, 2, -2);
+
+    CHECK_EQ(first.chunkCount(), second.chunkCount());
+    int mismatches = 0;
+    for (const auto& entry : first.allChunks()) {
+        const Chunk* twin = second.chunkAt(entry.first);
+        if (!twin || twin->raw() != entry.second->raw()) ++mismatches;
+    }
+    CHECK_EQ(mismatches, 0);
+}
+
+VF_TEST(endCentralIslandIsSurroundedByVoid) {
+    EndGenerator generator;
+    const EndGenerator::Params& params = generator.settings();
+
+    CHECK(!generator.isVoid(0, 0));
+    CHECK_EQ(generator.biomeAt(0, 0), EndBiome::CentralIsland);
+
+    int solidNearCentre = 0;
+    for (int gx = -40; gx <= 40; gx += 5)
+        for (int gz = -40; gz <= 40; gz += 5)
+            if (!generator.isVoid(gx, gz)) ++solidNearCentre;
+    CHECK(solidNearCentre > 200);
+
+    int intruders = 0;
+    int checkedRing = 0;
+    for (int gx = -600; gx <= 600; gx += 9) {
+        for (int gz = -600; gz <= 600; gz += 9) {
+            float distance = distanceFromOrigin(gx, gz);
+            if (distance <= params.centralRadius + params.edgeAmplitude) continue;
+            if (distance >= static_cast<float>(params.outerDistance)) continue;
+            ++checkedRing;
+            if (!generator.isVoid(gx, gz)) ++intruders;
+            if (generator.biomeAt(gx, gz) != EndBiome::Void) ++intruders;
+            if (generator.islandAt(gx, gz).valid()) ++intruders;
+        }
+    }
+    CHECK(checkedRing > 1000);
+    CHECK_EQ(intruders, 0);
+}
+
+VF_TEST(endIslandEdgeIsRaggedNotACleanCircle) {
+    EndGenerator generator;
+    const EndGenerator::Params& params = generator.settings();
+
+    int inside = 0;
+    int outside = 0;
+    for (int step = 0; step < 360; step += 3) {
+        float angle = 3.14159265f * static_cast<float>(step) / 180.0f;
+        int gx = static_cast<int>(std::lround(std::cos(angle) * params.centralRadius));
+        int gz = static_cast<int>(std::lround(std::sin(angle) * params.centralRadius));
+        if (generator.isVoid(gx, gz)) ++outside;
+        else ++inside;
+    }
+    CHECK(inside > 0);
+    CHECK(outside > 0);
+}
+
+VF_TEST(endTerrainIsEndStoneUnderAnEmptySky) {
+    EndGenerator generator;
+    World world;
+    generator.generateColumn(world, 0, 0);
+
+    int surface = generator.surfaceHeight(8, 8);
+    CHECK(surface > generator.settings().floorY);
+    CHECK_EQ(world.blockAt(8, surface, 8), Block::EndStone);
+    CHECK(generator.isStone(8, surface, 8));
+    CHECK(!generator.isStone(8, surface + 1, 8));
+
+    int deepBottom = surface;
+    while (generator.isStone(8, deepBottom - 1, 8)) --deepBottom;
+    CHECK(deepBottom > generator.settings().floorY);
+    CHECK_EQ(world.blockAt(8, deepBottom - 1, 8), Block::Air);
+    CHECK_EQ(world.blockAt(8, 120, 8), Block::Air);
+}
+
+VF_TEST(voidColumnsReportNoSurfaceAtAll) {
+    EndGenerator generator;
+    CHECK(generator.isVoid(300, 300));
+    CHECK_EQ(generator.surfaceHeight(300, 300), generator.settings().floorY - 1);
+    CHECK(!generator.isStone(300, 52, 300));
+    CHECK_EQ(generator.biomeAt(300, 300), EndBiome::Void);
+
+    World world;
+    generator.generateColumn(world, 20, 20);
+    CHECK_EQ(tallyBlocks(world, Block::EndStone, 320, 320, 16, 128), 0);
+}
+
+VF_TEST(obsidianPillarsRingTheCentreDeterministically) {
+    EndGenerator generator;
+    const EndGenerator::Params& params = generator.settings();
+    std::vector<ObsidianPillar> ring = generator.pillars();
+    std::vector<ObsidianPillar> again = generator.pillars();
+
+    CHECK_EQ(ring.size(), static_cast<std::size_t>(params.pillarCount));
+    CHECK_EQ(again.size(), ring.size());
+