diff --git a/tests/testSchematic.cpp b/tests/testSchematic.cpp
index 7e0568f..408ca8c 100644
--- a/tests/testSchematic.cpp
+++ b/tests/testSchematic.cpp
@@ -159,3 +159,159 @@ VF_TEST(rotatingFourTimesByNinetyDegreesReturnsTheOriginal) {
     twoQuarters.rotate(Rotation::Cw90);
     CHECK(half.buffer().sameContent(twoQuarters.buffer()));
 
+    Schematic backAgain = original;
+    backAgain.rotate(Rotation::Cw90);
+    backAgain.rotate(Rotation::Cw270);
+    CHECK(backAgain.buffer().sameContent(original.buffer()));
+}
+
+VF_TEST(aQuarterTurnSwapsTheHorizontalDimensionsAndMovesTheMarker) {
+    ClipboardBuffer buffer({4, 1, 2}, {0, 0, 0});
+    for (int z = 0; z < 2; ++z)
+        for (int x = 0; x < 4; ++x) buffer.put(x, 0, z, Block::Stone);
+    buffer.put(0, 0, 0, Block::Glowstone);
+
+    ClipboardBuffer turned = buffer.rotatedY(Rotation::Cw90);
+    CHECK(turned.dims() == Vec3i(2, 1, 4));
+    CHECK_EQ(turned.filledCount(), 8u);
+    // (0,0,0) maps to (dimZ - 1, 0, 0) under a clockwise quarter turn.
+    CHECK(turned.at(1, 0, 0) == Block::Glowstone);
+    CHECK(turned.at(0, 0, 0) == Block::Stone);
+}
+
+VF_TEST(mirroringTwiceOnTheSameAxisReturnsTheOriginal) {
+    ClipboardBuffer buffer({3, 2, 4}, {1, 0, 2});
+    for (int y = 0; y < 2; ++y)
+        for (int z = 0; z < 4; ++z)
+            for (int x = 0; x < 3; ++x) buffer.put(x, y, z, Block::Planks);
+    buffer.put(0, 0, 0, Block::Chest);
+
+    ClipboardBuffer flipped = buffer.mirrored(MirrorAxis::X);
+    CHECK(flipped.at(2, 0, 0) == Block::Chest);
+    CHECK(flipped.at(0, 0, 0) == Block::Planks);
+    CHECK(flipped.anchor() == Vec3i(1, 0, 2));
+
+    CHECK(flipped.mirrored(MirrorAxis::X).sameContent(buffer));
+    CHECK(buffer.mirrored(MirrorAxis::Y).mirrored(MirrorAxis::Y).sameContent(buffer));
+    CHECK(buffer.mirrored(MirrorAxis::Z).mirrored(MirrorAxis::Z).sameContent(buffer));
+
+    ClipboardBuffer alongZ = buffer.mirrored(MirrorAxis::Z);
+    CHECK(alongZ.at(0, 0, 3) == Block::Chest);
+    CHECK(alongZ.anchor() == Vec3i(1, 0, 1));
+}
+
+VF_TEST(trimmingDropsEmptyMarginsAndKeepsTheAnchorOnTheSameBlock) {
+    ClipboardBuffer padded({8, 8, 8}, {5, 5, 5});
+    for (int y = 4; y <= 5; ++y)
+        for (int z = 4; z <= 6; ++z)
+            for (int x = 5; x <= 6; ++x) padded.put(x, y, z, Block::Bricks);
+
+    ClipboardBuffer tight = padded.trimmed();
+    CHECK(tight.dims() == Vec3i(2, 2, 3));
+    CHECK_EQ(tight.filledCount(), 12u);
+    CHECK(tight.anchor() == Vec3i(0, 1, 1));
+    CHECK(tight.at(0, 0, 0) == Block::Bricks);
+
+    World empty;
+    Schematic schematic = Schematic::fromBuffer(padded, "pad", "foksiu", 3u);
+    schematic.trim();
+    CHECK(schematic.header().dims == Vec3i(2, 2, 3));
+    CHECK_EQ(schematic.pasteInto(empty, {0, 0, 0}, ClipboardBuffer::PasteMode::Overwrite), 12u);
+}
+
+VF_TEST(versionOneDataIsMigratedToVersionTwoWhenLoaded) {
+    World source = terrainWorld(6, 6);
+    Schematic saved = Schematic::capture(source, Selection::box({0, 0, 0}, {5, 4, 5}), "legacy",
+                                         "foksiu", 777u);
+
+    ByteBuffer oldBytes = saved.encode(SchematicVersion::V1);
+    ByteBuffer newBytes = saved.encode(SchematicVersion::V2);
+    CHECK(oldBytes.size() < newBytes.size());
+
+    SchematicError error = SchematicError::BadMagic;
+    Schematic loaded = decodedCopy(oldBytes, error);
+    CHECK(error == SchematicError::None);
+    CHECK(loaded.migratedFromV1());
+    CHECK(loaded.header().version == SchematicVersion::V2);
+    CHECK(loaded.header().name.empty());
+    CHECK(loaded.header().author.empty());
+    CHECK_EQ(loaded.header().tick, 0u);
+    CHECK(loaded.buffer().sameContent(saved.buffer()));
+
+    // Re-saving the migrated schematic yields a v2 buffer that carries metadata.
+    loaded.setName("legacy");
+    loaded.setAuthor("foksiu");
+    loaded.setTick(777u);
+    SchematicError second = SchematicError::BadMagic;
+    Schematic again = decodedCopy(loaded.encode(), second);
+    CHECK(second == SchematicError::None);
+    CHECK(!again.migratedFromV1());
+    CHECK(again.header().name == std::string("legacy"));
+}
+
+VF_TEST(theVoidMaskKeepsHolesInVersionTwoAndIsLostInVersionOne) {
+    World stoneBlock;
+    for (int y = 0; y < 9; ++y)
+        for (int z = 0; z < 9; ++z)
+            for (int x = 0; x < 9; ++x) stoneBlock.setBlock(x, y, z, Block::Stone);
+
+    Selection ball = Selection::sphere({4, 4, 4}, 4);
+    Schematic saved = Schematic::capture(stoneBlock, ball, "ball", "foksiu", 5u);
+    CHECK(saved.header().hasVoidMask);
+    CHECK(saved.buffer().filledCount() < saved.buffer().volume());
+
+    SchematicError error = SchematicError::BadMagic;
+    Schematic loaded = decodedCopy(saved.encode(), error);
+    CHECK(error == SchematicError::None);
+    CHECK(loaded.header().hasVoidMask);
+    CHECK_EQ(loaded.buffer().filledCount(), saved.buffer().filledCount());
+    CHECK(!loaded.buffer().filledAt(0, 0, 0));
+
+    SchematicError legacyError = SchematicError::BadMagic;
+    Schematic legacy = decodedCopy(saved.encode(SchematicVersion::V1), legacyError);
+    CHECK(legacyError == SchematicError::None);
+    CHECK(!legacy.header().hasVoidMask);
+    CHECK_EQ(legacy.buffer().filledCount(), legacy.buffer().volume());
+    CHECK(legacy.buffer().at(0, 0, 0) == Block::Air);
+
+    World target;
+    loaded.pasteInto(target, {0, 0, 0}, ClipboardBuffer::PasteMode::Overwrite);
+    CHECK(target.blockAt(4, 4, 4) == Block::Stone);
+    CHECK(target.blockAt(0, 0, 0) == Block::Air);
+    CHECK(target.blockAt(8, 8, 8) == Block::Air);
+}
+
+VF_TEST(aBufferWithTheWrongMagicNumberIsRejected) {
+    World source = terrainWorld(3, 3);
+    ByteBuffer bytes =
+        Schematic::capture(source, Selection::box({0, 0, 0}, {2, 2, 2}), "m", "f", 1u).encode();
+    bytes[0] = 0x00;
+
+    Schematic loaded;
+    CHECK(Schematic::decode(bytes.data(), bytes.size(), loaded) == SchematicError::BadMagic);
+
+    ByteBuffer garbage = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};
+    CHECK(Schematic::decode(garbage.data(), garbage.size(), loaded) == SchematicError::BadMagic);
+}
+
+VF_TEST(anUnknownFormatVersionIsRejected) {
+    World source = terrainWorld(3, 3);
+    ByteBuffer bytes =
+        Schematic::capture(source, Selection::box({0, 0, 0}, {2, 2, 2}), "v", "f", 1u).encode();
+    writeU32(bytes, 4, 7u);
+
+    Schematic loaded;
+    CHECK(Schematic::decode(bytes.data(), bytes.size(), loaded) ==
+          SchematicError::UnsupportedVersion);
+
+    writeU32(bytes, 4, 0u);
+    CHECK(Schematic::decode(bytes.data(), bytes.size(), loaded) ==
+          SchematicError::UnsupportedVersion);
+}
+
+VF_TEST(aTruncatedBufferIsRejectedAtEveryCutPoint) {
+    World source = terrainWorld(5, 5);
+    ByteBuffer bytes =
+        Schematic::capture(source, Selection::box({0, 0, 0}, {4, 4, 4}), "cut", "f", 1u).encode();
+    CHECK(bytes.size() > 40u);
+