Add linking game tests

src/main/java/net/dnorberg/rivencraft/gametest/LinkingGameTests.java

@@ -0,0 +1,78 @@
+package net.dnorberg.rivencraft.gametest;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.book.LinkTarget;
+import net.dnorberg.rivencraft.book.LinkingService;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.GlobalPos;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.block.Blocks;
+import net.neoforged.neoforge.gametest.GameTestHolder;
+import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
+
+/** Server-side regression coverage for persistent linking-book data and travel safety. */
+@GameTestHolder(Rivencraft.MOD_ID)
+@PrefixGameTestTemplate(false)
+public final class LinkingGameTests {
+    private static final BlockPos ORIGIN = new BlockPos(0, 1, 0);
+
+    private LinkingGameTests() {
+    }
+
+    @GameTest(template = "empty")
+    public static void linkTargetSurvivesItemSerialization(GameTestHelper helper) {
+        LinkTarget expected = new LinkTarget(
+                GlobalPos.of(helper.getLevel().dimension(), helper.absolutePos(ORIGIN)),
+                127.5F,
+                -31.25F
+        );
+        ItemStack book = new ItemStack(ModItems.LINKING_BOOK.get());
+        book.set(ModDataComponents.LINK_TARGET.get(), expected);
+
+        CompoundTag serialized = (CompoundTag) book.saveOptional(helper.getLevel().registryAccess());
+        ItemStack restored = ItemStack.parseOptional(helper.getLevel().registryAccess(), serialized);
+
+        helper.assertValueEqual(restored.get(ModDataComponents.LINK_TARGET.get()), expected,
+                "A Linking Book must retain its dimension, position, and orientation after serialization");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void travelUsesRecordedSafePosition(GameTestHelper helper) {
+        helper.setBlock(ORIGIN.below(), Blocks.STONE);
+        BlockPos destination = helper.absolutePos(ORIGIN);
+        ServerPlayer player = helper.makeMockServerPlayerInLevel();
+        LinkTarget target = new LinkTarget(GlobalPos.of(helper.getLevel().dimension(), destination), 90.0F, 15.0F);
+
+        LinkingService.LinkResult result = LinkingService.travel(player, target);
+
+        helper.assertValueEqual(result, LinkingService.LinkResult.SUCCESS,
+                "A Linking Book must travel to a clear location with a sturdy floor");
+        helper.assertTrue(player.level() == helper.getLevel(), "Travel must remain in the recorded dimension");
+        helper.assertTrue(Math.abs(player.getYRot() - 90.0F) < 0.01F && Math.abs(player.getXRot() - 15.0F) < 0.01F,
+                "Travel must restore the recorded orientation");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void travelRejectsBlockedDestination(GameTestHelper helper) {
+        BlockPos absoluteOrigin = helper.absolutePos(ORIGIN);
+        for (BlockPos position : BlockPos.betweenClosed(
+                absoluteOrigin.offset(-4, -2, -4), absoluteOrigin.offset(4, 2, 4))) {
+            helper.getLevel().setBlockAndUpdate(position, Blocks.STONE.defaultBlockState());
+        }
+
+        ServerPlayer player = helper.makeMockServerPlayerInLevel();
+        LinkTarget target = new LinkTarget(GlobalPos.of(helper.getLevel().dimension(), absoluteOrigin), 0.0F, 0.0F);
+
+        helper.assertValueEqual(LinkingService.travel(player, target), LinkingService.LinkResult.NO_SAFE_DESTINATION,
+                "Linking must fail rather than placing a player inside a blocked destination");
+        helper.succeed();
+    }
+}