diff --git a/tests/testSaveMigration.cpp b/tests/testSaveMigration.cpp
index 8313d3c..414ba8f 100644
--- a/tests/testSaveMigration.cpp
+++ b/tests/testSaveMigration.cpp
@@ -313,3 +313,110 @@ VF_TEST(peekVersionReadsTheHeaderWithoutTheBody) {
     ByteBuffer buffer = writeSaveContainer(original);
     ByteBuffer headerOnly(buffer.begin(), buffer.begin() + saveHeaderBytes);
 
+    SaveVersion version = SaveVersion::V1;
+    CHECK(SaveMigrator::peekVersion(headerOnly.data(), headerOnly.size(), version));
+    CHECK(version == SaveVersion::V3);
+
+    ByteBuffer shorter(buffer.begin(), buffer.begin() + 12);
+    CHECK(!SaveMigrator::peekVersion(shorter.data(), shorter.size(), version));
+}
+
+VF_TEST(defaultLightIsBlockedByOpaqueBlocksAndLitByEmitters) {
+    Chunk chunk;
+    chunk.set(0, 0, 0, Block::Air);
+    chunk.set(1, 0, 0, Block::Stone);
+    chunk.set(2, 0, 0, Block::Glowstone);
+
+    std::vector<uint8_t> plane = defaultChunkLight(chunk, saveDefaultSkyLight);
+    CHECK_EQ(plane.size(), static_cast<std::size_t>(chunkVolume));
+
+    uint8_t openCell = plane[static_cast<std::size_t>(localIndex(0, 0, 0))];
+    uint8_t stoneCell = plane[static_cast<std::size_t>(localIndex(1, 0, 0))];
+    uint8_t lampCell = plane[static_cast<std::size_t>(localIndex(2, 0, 0))];
+
+    CHECK_EQ(static_cast<int>(openCell >> 4), 15);
+    CHECK_EQ(static_cast<int>(openCell & 0x0F), 0);
+    CHECK_EQ(static_cast<int>(stoneCell >> 4), 0);
+    CHECK_EQ(static_cast<int>(lampCell & 0x0F), blockLightEmission(Block::Glowstone));
+
+    std::vector<uint8_t> dim = defaultChunkLight(chunk, 4);
+    CHECK_EQ(static_cast<int>(dim[static_cast<std::size_t>(localIndex(0, 0, 0))] >> 4), 4);
+}
+
+VF_TEST(worldImportKeepsOnlyTheChunksOfTheAskedForRegion) {
+    World world;
+    world.ensureChunk({1, 0, 1}) = texturedChunk(1);
+    world.ensureChunk({2, 3, 4}) = texturedChunk(2);
+    world.ensureChunk({20, 0, 0}) = texturedChunk(3);
+    world.ensureChunk({5, 0, 5});
+
+    SaveContainer container = saveContainerFromWorld(world, RegionCoord{0, 0}, currentSaveVersion);
+    CHECK_EQ(container.chunks.size(), static_cast<std::size_t>(2));
+    CHECK(container.find({1, 0, 1}) != nullptr);
+    CHECK(container.find({2, 3, 4}) != nullptr);
+    CHECK(container.find({20, 0, 0}) == nullptr);
+    CHECK(container.find({5, 0, 5}) == nullptr);
+
+    SaveContainer neighbour = saveContainerFromWorld(world, RegionCoord{1, 0}, currentSaveVersion);
+    CHECK_EQ(neighbour.chunks.size(), static_cast<std::size_t>(1));
+    CHECK(neighbour.find({20, 0, 0}) != nullptr);
+}
+
+VF_TEST(applyingAContainerBackToAWorldRestoresTheBlocks) {
+    World source;
+    source.ensureChunk({1, 0, 1}) = texturedChunk(11);
+    source.ensureChunk({2, 1, 3}) = texturedChunk(12);
+
+    SaveContainer container = saveContainerFromWorld(source, RegionCoord{0, 0}, currentSaveVersion);
+    ByteBuffer buffer = writeSaveContainer(container);
+
+    SaveContainer reloaded;
+    CHECK(readSaveContainer(buffer.data(), buffer.size(), reloaded));
+    World rebuilt;
+    applySaveContainerToWorld(reloaded, rebuilt);
+
+    CHECK_EQ(rebuilt.chunkCount(), static_cast<std::size_t>(2));
+    CHECK(sameBlocks(*source.chunkAt({1, 0, 1}), *rebuilt.chunkAt({1, 0, 1})));
+    CHECK(sameBlocks(*source.chunkAt({2, 1, 3}), *rebuilt.chunkAt({2, 1, 3})));
+}
+
+VF_TEST(payloadBytesCanBePulledOutOfAContainerVerbatim) {
+    SaveContainer container = buildContainer(SaveVersion::V4, 3);
+    ByteBuffer buffer = writeSaveContainer(container);
+
+    ByteBuffer payload;
+    CHECK(readChunkPayloadBytes(buffer.data(), buffer.size(), Vec3i{1, 0, 3}, payload));
+    CHECK(!payload.empty());
+
+    SaveChunkRecord decoded;
+    CHECK(decodeChunkPayload(SaveVersion::V4, payload.data(), payload.size(), decoded));
+    const SaveChunkRecord* original = container.find({1, 0, 3});
+    CHECK(original != nullptr);
+    if (original != nullptr) CHECK(sameBlocks(original->blocks, decoded.blocks));
+
+    ByteBuffer missing;
+    CHECK(!readChunkPayloadBytes(buffer.data(), buffer.size(), Vec3i{9, 9, 9}, missing));
+}
+
+VF_TEST(recordChecksumCoversTheBodyAndNotItsFraming) {
+    SaveContainer container = buildContainer(SaveVersion::V4, 1);
+    const SaveChunkRecord& record = container.chunks[0];
+
+    ByteBuffer loose = encodeChunkPayload(SaveVersion::V4, record, false);
+    ByteBuffer tight = encodeChunkPayload(SaveVersion::V4, record, true);
+    CHECK(tight.size() < loose.size());
+
+    uint32_t looseStored = 0, looseComputed = 0, tightStored = 0, tightComputed = 0;
+    CHECK(verifyChunkPayloadChecksum(SaveVersion::V4, loose.data(), loose.size(), looseStored,
+                                     looseComputed));
+    CHECK(verifyChunkPayloadChecksum(SaveVersion::V4, tight.data(), tight.size(), tightStored,
+                                     tightComputed));
+    CHECK_EQ(looseStored, looseComputed);
+    CHECK_EQ(tightStored, tightComputed);
+    CHECK_EQ(looseStored, tightStored);
+
+    uint32_t stored = 0, computed = 0;
+    ByteBuffer ancient = encodeChunkPayload(SaveVersion::V1, record, false);
+    CHECK(!verifyChunkPayloadChecksum(SaveVersion::V1, ancient.data(), ancient.size(), stored,
+                                      computed));
+}