Merge branch 'mc-1.16.x' into mc-1.18.x

build.gradle

@@ -88,6 +88,23 @@ minecraft {
             args '--mod', 'computercraft', '--all', '--output', file('src/generated/resources/'), '--existing', file('src/main/resources/')
         }
 
+        testClient {
+            workingDirectory project.file('test-files/client')
+            parent runs.client
+
+            mods {
+                cctest {
+                    source sourceSets.testMod
+                }
+            }
+
+            lazyToken('minecraft_classpath') {
+                (configurations.shade.copyRecursive().resolve() + configurations.testModExtra.copyRecursive().resolve())
+                    .collect { it.absolutePath }
+                    .join(File.pathSeparator)
+            }
+        }
+
         gameTestServer {
             workingDirectory project.file('test-files/server')
 

src/main/java/dan200/computercraft/ComputerCraftAPIImpl.java

@@ -6,6 +6,7 @@
 package dan200.computercraft;
 
 import dan200.computercraft.api.ComputerCraftAPI.IComputerCraftAPI;
+import dan200.computercraft.api.detail.IDetailProvider;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.lua.GenericSource;
@@ -24,6 +25,7 @@ import dan200.computercraft.shared.BundledRedstone;
 import dan200.computercraft.shared.MediaProviders;
 import dan200.computercraft.shared.Peripherals;
 import dan200.computercraft.shared.peripheral.generic.GenericPeripheralProvider;
+import dan200.computercraft.shared.peripheral.generic.data.DetailProviders;
 import dan200.computercraft.shared.peripheral.modem.wireless.WirelessNetwork;
 import dan200.computercraft.shared.util.IDAssigner;
 import dan200.computercraft.shared.wired.WiredNode;
@@ -155,6 +157,12 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
         ApiFactories.register( factory );
     }
 
+    @Override
+    public <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider )
+    {
+        DetailProviders.registerProvider( type, provider );
+    }
+
     @Nonnull
     @Override
     public IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element )

src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -5,6 +5,8 @@
  */
 package dan200.computercraft.api;
 
+import dan200.computercraft.api.detail.BlockReference;
+import dan200.computercraft.api.detail.IDetailProvider;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.lua.GenericSource;
@@ -20,10 +22,12 @@ import dan200.computercraft.api.peripheral.IPeripheralProvider;
 import dan200.computercraft.api.redstone.IBundledRedstoneProvider;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.BlockGetter;
 import net.minecraft.world.level.Level;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.util.LazyOptional;
+import net.minecraftforge.fluids.FluidStack;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -196,6 +200,20 @@ public final class ComputerCraftAPI
         getInstance().registerAPIFactory( factory );
     }
 
+    /**
+     * Registers a detail provider to provide additional details for blocks, fluids and items when inspected by methods
+     * such as {@code turtle.getItemDetail()} or {@code turtle.inspect()}.
+     *
+     * @param type     The type of object that this provider can provide details for. Should be {@link BlockReference},
+     *                 {@link FluidStack} or {@link ItemStack}.
+     * @param provider The detail provider to register.
+     * @param <T>      The type of object that this provider can provide details for.
+     */
+    public static <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider )
+    {
+        getInstance().registerDetailProvider( type, provider );
+    }
+
     /**
      * Construct a new wired node for a given wired element.
      *
@@ -272,6 +290,8 @@ public final class ComputerCraftAPI
 
         void registerAPIFactory( @Nonnull ILuaAPIFactory factory );
 
+        <T> void registerDetailProvider( @Nonnull Class<T> type, @Nonnull IDetailProvider<T> provider );
+
         @Nonnull
         IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element );
 

src/main/java/dan200/computercraft/api/detail/BasicItemDetailProvider.java

@@ -0,0 +1,79 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.detail;
+
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+
+import javax.annotation.Nonnull;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * An item detail provider for {@link ItemStack}'s whose {@link Item} has a specific type.
+ *
+ * @param <T> The type the stack's item must have.
+ */
+public abstract class BasicItemDetailProvider<T> implements IDetailProvider<ItemStack>
+{
+    private final Class<T> itemType;
+    private final String namespace;
+
+    /**
+     * Create a new item detail provider. Meta will be inserted into a new sub-map named as per {@code namespace}.
+     *
+     * @param itemType  The type the stack's item must have.
+     * @param namespace The namespace to use for this provider.
+     */
+    public BasicItemDetailProvider( String namespace, @Nonnull Class<T> itemType )
+    {
+        Objects.requireNonNull( itemType );
+        this.itemType = itemType;
+        this.namespace = namespace;
+    }
+
+    /**
+     * Create a new item detail provider. Meta will be inserted directly into the results.
+     *
+     * @param itemType The type the stack's item must have.
+     */
+    public BasicItemDetailProvider( @Nonnull Class<T> itemType )
+    {
+        this( null, itemType );
+    }
+
+    /**
+     * Provide additional details for the given {@link Item} and {@link ItemStack}. This method is called by
+     * {@code turtle.getItemDetail()}. New properties should be added to the given {@link Map}, {@code data}.
+     *
+     * This method is always called on the server thread, so it is safe to interact with the world here, but you should
+     * take care to avoid long blocking operations as this will stall the server and other computers.
+     *
+     * @param data  The full details to be returned for this item stack. New properties should be added to this map.
+     * @param stack The item stack to provide details for.
+     * @param item  The item to provide details for.
+     */
+    public abstract void provideDetails( @Nonnull Map<? super String, Object> data, @Nonnull ItemStack stack,
+                                         @Nonnull T item );
+
+    @Override
+    public void provideDetails( @Nonnull Map<? super String, Object> data, @Nonnull ItemStack stack )
+    {
+        Item item = stack.getItem();
+        if( !itemType.isInstance( item ) ) return;
+
+        // If `namespace` is specified, insert into a new data map instead of the existing one.
+        Map<? super String, Object> child = namespace == null ? data : new HashMap<>();
+
+        provideDetails( child, stack, itemType.cast( item ) );
+
+        if( namespace != null )
+        {
+            data.put( namespace, child );
+        }
+    }
+}

src/main/java/dan200/computercraft/api/detail/BlockReference.java

@@ -0,0 +1,35 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.detail;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.state.BlockState;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * A reference to a block in the world, used by block detail providers.
+ *
+ * @param level       The level the block exists in.
+ * @param pos         The position of the block.
+ * @param state       The block state at this position.
+ * @param blockEntity The block entity at this position, if it exists.
+ */
+public record BlockReference(
+    @Nonnull Level level,
+    @Nonnull BlockPos pos,
+    @Nonnull BlockState state,
+    @Nullable BlockEntity blockEntity
+)
+{
+    public BlockReference( Level level, BlockPos pos )
+    {
+        this( level, pos, level.getBlockState( pos ), level.getBlockEntity( pos ) );
+    }
+}

src/main/java/dan200/computercraft/api/detail/IDetailProvider.java

@@ -0,0 +1,32 @@
+/*
+ * This file is part of the public ComputerCraft API - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. This API may be redistributed unmodified and in full only.
+ * For help using the API, and posting your mods, visit the forums at computercraft.info.
+ */
+package dan200.computercraft.api.detail;
+
+import javax.annotation.Nonnull;
+import java.util.Map;
+
+/**
+ * This interface is used to provide details about a block, fluid, or item.
+ *
+ * @param <T> The type of object that this provider can provide details for.
+ * @see dan200.computercraft.api.ComputerCraftAPI#registerDetailProvider(Class, IDetailProvider)
+ */
+@FunctionalInterface
+public interface IDetailProvider<T>
+{
+    /**
+     * Provide additional details for the given object. This method is called by functions such as
+     * {@code turtle.getItemDetail()} and {@code turtle.inspect()}. New properties should be added to the given
+     * {@link Map}, {@code data}.
+     *
+     * This method is always called on the server thread, so it is safe to interact with the world here, but you should
+     * take care to avoid long blocking operations as this will stall the server and other computers.
+     *
+     * @param data   The full details to be returned. New properties should be added to this map.
+     * @param object The object to provide details for.
+     */
+    void provideDetails( @Nonnull Map<? super String, Object> data, @Nonnull T object );
+}

src/main/java/dan200/computercraft/client/gui/ComputerScreenBase.java

@@ -58,7 +58,7 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
     protected abstract WidgetTerminal createTerminal();
 
     @Override
-    protected final void init()
+    protected void init()
     {
         super.init();
         minecraft.keyboardHandler.setSendRepeatsToGui( true );
@@ -69,21 +69,21 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
     }
 
     @Override
-    public final void removed()
+    public void removed()
     {
         super.removed();
         minecraft.keyboardHandler.setSendRepeatsToGui( false );
     }
 
     @Override
-    public final void containerTick()
+    public void containerTick()
     {
         super.containerTick();
         terminal.update();
     }
 
     @Override
-    public final boolean keyPressed( int key, int scancode, int modifiers )
+    public boolean keyPressed( int key, int scancode, int modifiers )
     {
         // Forward the tab key to the terminal, rather than moving between controls.
         if( key == GLFW.GLFW_KEY_TAB && getFocused() != null && getFocused() == terminal )
@@ -96,7 +96,7 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
 
 
     @Override
-    public final void render( @Nonnull PoseStack stack, int mouseX, int mouseY, float partialTicks )
+    public void render( @Nonnull PoseStack stack, int mouseX, int mouseY, float partialTicks )
     {
         renderBackground( stack );
         super.render( stack, mouseX, mouseY, partialTicks );
@@ -114,7 +114,7 @@ public abstract class ComputerScreenBase<T extends ContainerComputerBase> extend
     }
 
     @Override
-    public final boolean mouseDragged( double x, double y, int button, double deltaX, double deltaY )
+    public boolean mouseDragged( double x, double y, int button, double deltaX, double deltaY )
     {
         return (getFocused() != null && getFocused().mouseDragged( x, y, button, deltaX, deltaY ))
             || super.mouseDragged( x, y, button, deltaX, deltaY );

src/main/java/dan200/computercraft/core/lua/CobaltLuaMachine.java

@@ -6,7 +6,10 @@
 package dan200.computercraft.core.lua;
 
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.api.lua.*;
+import dan200.computercraft.api.lua.IDynamicLuaObject;
+import dan200.computercraft.api.lua.ILuaAPI;
+import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.ILuaFunction;
 import dan200.computercraft.core.asm.LuaMethod;
 import dan200.computercraft.core.asm.ObjectSource;
 import dan200.computercraft.core.computer.Computer;
@@ -14,7 +17,6 @@ import dan200.computercraft.core.computer.TimeoutState;
 import dan200.computercraft.core.tracking.Tracking;
 import dan200.computercraft.core.tracking.TrackingField;
 import dan200.computercraft.shared.util.ThreadUtils;
-import org.squiddev.cobalt.LuaTable;
 import org.squiddev.cobalt.*;
 import org.squiddev.cobalt.compiler.CompileException;
 import org.squiddev.cobalt.compiler.LoadState;

src/main/java/dan200/computercraft/core/lua/ResultInterpreterFunction.java

@@ -6,7 +6,10 @@
 package dan200.computercraft.core.lua;
 
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.api.lua.*;
+import dan200.computercraft.api.lua.ILuaCallback;
+import dan200.computercraft.api.lua.ILuaContext;
+import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.lua.MethodResult;
 import dan200.computercraft.core.asm.LuaMethod;
 import org.squiddev.cobalt.*;
 import org.squiddev.cobalt.debug.DebugFrame;

src/main/java/dan200/computercraft/shared/computer/apis/CommandAPI.java

@@ -8,6 +8,7 @@ package dan200.computercraft.shared.computer.apis;
 import com.mojang.brigadier.tree.CommandNode;
 import com.mojang.brigadier.tree.LiteralCommandNode;
 import dan200.computercraft.ComputerCraft;
+import dan200.computercraft.api.detail.BlockReference;
 import dan200.computercraft.api.lua.*;
 import dan200.computercraft.shared.computer.blocks.TileCommandComputer;
 import dan200.computercraft.shared.peripheral.generic.data.BlockData;
@@ -21,7 +22,6 @@ import net.minecraft.resources.ResourceLocation;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.entity.BlockEntity;
-import net.minecraft.world.level.block.state.BlockState;
 
 import javax.annotation.Nonnull;
 import java.util.*;
@@ -76,10 +76,10 @@ public class CommandAPI implements ILuaAPI
     private static Map<?, ?> getBlockInfo( Level world, BlockPos pos )
     {
         // Get the details of the block
-        BlockState state = world.getBlockState( pos );
+        BlockReference block = new BlockReference( world, pos );
-        Map<String, Object> table = BlockData.fill( new HashMap<>(), state );
+        Map<String, Object> table = BlockData.fill( new HashMap<>(), block );
 
-        BlockEntity tile = world.getBlockEntity( pos );
+        BlockEntity tile = block.blockEntity();
         if( tile != null ) table.put( "nbt", NBTUtil.toLua( tile.saveWithFullMetadata() ) );
 
         return table;

src/main/java/dan200/computercraft/shared/peripheral/generic/data/BlockData.java

@@ -5,6 +5,7 @@
  */
 package dan200.computercraft.shared.peripheral.generic.data;
 
+import dan200.computercraft.api.detail.BlockReference;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.block.state.properties.Property;
 
@@ -15,8 +16,10 @@ import java.util.Map;
 public class BlockData
 {
     @Nonnull
-    public static <T extends Map<? super String, Object>> T fill( @Nonnull T data, @Nonnull BlockState state )
+    public static <T extends Map<? super String, Object>> T fill( @Nonnull T data, @Nonnull BlockReference block )
     {
+        BlockState state = block.state();
+
         data.put( "name", DataHelpers.getId( state.getBlock() ) );
 
         Map<Object, Object> stateTable = new HashMap<>();
@@ -28,6 +31,8 @@ public class BlockData
         data.put( "state", stateTable );
         data.put( "tags", DataHelpers.getTags( state.getTags() ) );
 
+        DetailProviders.fillData( BlockReference.class, data, block );
+
         return data;
     }
 

src/main/java/dan200/computercraft/shared/peripheral/generic/data/DetailProviders.java

@@ -0,0 +1,43 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+package dan200.computercraft.shared.peripheral.generic.data;
+
+import dan200.computercraft.api.detail.BlockReference;
+import dan200.computercraft.api.detail.IDetailProvider;
+import net.minecraft.world.item.ItemStack;
+import net.minecraftforge.fluids.FluidStack;
+
+import java.util.*;
+
+public final class DetailProviders
+{
+    private static final Map<Class<?>, Collection<IDetailProvider<?>>> allProviders = new HashMap<>();
+
+    public static synchronized <T> void registerProvider( Class<T> type, IDetailProvider<T> provider )
+    {
+        Objects.requireNonNull( type, "type cannot be null" );
+        Objects.requireNonNull( provider, "provider cannot be null" );
+
+        if( type != BlockReference.class && type != ItemStack.class && type != FluidStack.class )
+        {
+            throw new IllegalArgumentException( "type must be assignable from BlockReference, ItemStack or FluidStack" );
+        }
+
+        allProviders.computeIfAbsent( type, k -> new LinkedHashSet<>() ).add( provider );
+    }
+
+    @SuppressWarnings( "unchecked" )
+    public static <T> void fillData( Class<T> type, Map<? super String, Object> data, T value )
+    {
+        Collection<IDetailProvider<T>> providers = (Collection<IDetailProvider<T>>) (Object) allProviders.get( type );
+        if( providers == null ) return;
+
+        for( IDetailProvider<T> provider : providers )
+        {
+            provider.provideDetails( data, value );
+        }
+    }
+}

src/main/java/dan200/computercraft/shared/peripheral/generic/data/FluidData.java

@@ -24,10 +24,13 @@ public class FluidData
     public static <T extends Map<? super String, Object>> T fill( @Nonnull T data, @Nonnull FluidStack stack )
     {
         fillBasic( data, stack );
+
         // FluidStack doesn't have a getTags method, so we need to use the deprecated builtInRegistryHolder.
         @SuppressWarnings( "deprecation" )
         var holder = stack.getFluid().builtInRegistryHolder();
         data.put( "tags", DataHelpers.getTags( holder ) );
+
+        DetailProviders.fillData( FluidStack.class, data, stack );
         return data;
     }
 }

src/main/java/dan200/computercraft/shared/peripheral/generic/data/ItemData.java

@@ -97,6 +97,8 @@ public class ItemData
             data.put( "unbreakable", true );
         }
 
+        DetailProviders.fillData( ItemStack.class, data, stack );
+
         return data;
     }
 

src/main/java/dan200/computercraft/shared/peripheral/printer/ContainerPrinter.java

@@ -7,6 +7,7 @@ package dan200.computercraft.shared.peripheral.printer;
 
 import dan200.computercraft.shared.Registry;
 import dan200.computercraft.shared.util.SingleIntArray;
+import dan200.computercraft.shared.util.ValidatingSlot;
 import net.minecraft.world.Container;
 import net.minecraft.world.SimpleContainer;
 import net.minecraft.world.entity.player.Inventory;
@@ -33,13 +34,16 @@ public class ContainerPrinter extends AbstractContainerMenu
         addDataSlots( properties );
 
         // Ink slot
-        addSlot( new Slot( inventory, 0, 13, 35 ) );
+        addSlot( new ValidatingSlot( inventory, 0, 13, 35, TilePrinter::isInk ) );
 
         // In-tray
-        for( int x = 0; x < 6; x++ ) addSlot( new Slot( inventory, x + 1, 61 + x * 18, 22 ) );
+        for( int x = 0; x < 6; x++ )
+        {
+            addSlot( new ValidatingSlot( inventory, x + 1, 61 + x * 18, 22, TilePrinter::isPaper ) );
+        }
 
         // Out-tray
-        for( int x = 0; x < 6; x++ ) addSlot( new Slot( inventory, x + 7, 61 + x * 18, 49 ) );
+        for( int x = 0; x < 6; x++ ) addSlot( new ValidatingSlot( inventory, x + 7, 61 + x * 18, 49, o -> false ) );
 
         // Player inv
         for( int y = 0; y < 3; y++ )

src/main/java/dan200/computercraft/shared/peripheral/printer/TilePrinter.java

@@ -308,7 +308,7 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         return ColourUtils.getStackColour( stack ) != null;
     }
 
-    private static boolean isPaper( @Nonnull ItemStack stack )
+    static boolean isPaper( @Nonnull ItemStack stack )
     {
         Item item = stack.getItem();
         return item == Items.PAPER

src/main/java/dan200/computercraft/shared/turtle/core/TurtleInspectCommand.java

@@ -5,6 +5,7 @@
  */
 package dan200.computercraft.shared.turtle.core;
 
+import dan200.computercraft.api.detail.BlockReference;
 import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.ITurtleCommand;
 import dan200.computercraft.api.turtle.TurtleCommandResult;
@@ -12,7 +13,6 @@ import dan200.computercraft.shared.peripheral.generic.data.BlockData;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.world.level.Level;
-import net.minecraft.world.level.block.state.BlockState;
 
 import javax.annotation.Nonnull;
 import java.util.HashMap;
@@ -39,10 +39,10 @@ public class TurtleInspectCommand implements ITurtleCommand
         BlockPos oldPosition = turtle.getPosition();
         BlockPos newPosition = oldPosition.relative( direction );
 
-        BlockState state = world.getBlockState( newPosition );
+        BlockReference block = new BlockReference( world, newPosition );
-        if( state.isAir() ) return TurtleCommandResult.failure( "No block to inspect" );
+        if( block.state().isAir() ) return TurtleCommandResult.failure( "No block to inspect" );
 
-        Map<String, Object> table = BlockData.fill( new HashMap<>(), state );
+        Map<String, Object> table = BlockData.fill( new HashMap<>(), block );
 
         return TurtleCommandResult.success( new Object[] { table } );
 

src/main/java/dan200/computercraft/shared/util/ValidatingSlot.java

@@ -10,17 +10,21 @@ import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 
 import javax.annotation.Nonnull;
+import java.util.function.Predicate;
 
 public class ValidatingSlot extends Slot
 {
-    public ValidatingSlot( Container inventoryIn, int index, int xPosition, int yPosition )
+    private final Predicate<ItemStack> predicate;
+
+    public ValidatingSlot( Container inventoryIn, int index, int xPosition, int yPosition, Predicate<ItemStack> predicate )
     {
         super( inventoryIn, index, xPosition, yPosition );
+        this.predicate = predicate;
     }
 
     @Override
     public boolean mayPlace( @Nonnull ItemStack stack )
     {
-        return true; // inventory.isItemValidForSlot( slotNumber, stack );
+        return predicate.test( stack );
     }
 }

src/test/java/dan200/computercraft/core/apis/AsyncRunner.kt

@@ -107,7 +107,7 @@ class AsyncRunner : NullApiEnvironment() {
         private val empty: Array<Any?> = arrayOf()
 
         @OptIn(ExperimentalTime::class)
-        fun runTest(timeout: Duration = Duration.seconds(5), fn: suspend AsyncRunner.() -> Unit) {
+        fun runTest(timeout: Duration = 5.seconds, fn: suspend AsyncRunner.() -> Unit) {
             runBlocking {
                 val runner = AsyncRunner()
                 try {

src/test/java/dan200/computercraft/core/computer/ComputerThreadTest.java

@@ -85,7 +85,7 @@ public class ComputerThreadTest
             assertEquals( budget, TimeUnit.MILLISECONDS.toNanos( 25 ), "Budget should be 25ms" );
 
             long delay = ConcurrentHelpers.waitUntil( timeout::isPaused );
-            assertThat( "Paused within 25ms", delay * 1e-9, closeTo( 0.03, 0.015 ) );
+            assertThat( "Paused within 25ms", delay * 1e-9, closeTo( 0.03, 0.02 ) );
 
             computer.shutdown();
             return MachineResult.OK;

src/testMod/java/dan200/computercraft/ingame/TurtleTest.kt

@@ -1,11 +1,15 @@
 package dan200.computercraft.ingame
 
 import dan200.computercraft.ComputerCraft
+import dan200.computercraft.api.ComputerCraftAPI
+import dan200.computercraft.api.detail.BasicItemDetailProvider
 import dan200.computercraft.ingame.api.Timeouts.COMPUTER_TIMEOUT
 import dan200.computercraft.ingame.api.sequence
 import dan200.computercraft.ingame.api.thenComputerOk
+import dan200.computercraft.shared.media.items.ItemPrintout
 import net.minecraft.gametest.framework.GameTest
 import net.minecraft.gametest.framework.GameTestHelper
+import net.minecraft.world.item.ItemStack
 import net.minecraftforge.gametest.GameTestHolder
 
 @GameTestHolder(ComputerCraft.MOD_ID)
@@ -75,4 +79,25 @@ class Turtle_Test {
      */
     @GameTest(required = false)
     fun Cleaned_with_cauldrons(helper: GameTestHelper) = helper.sequence { thenComputerOk() }
+
+    /**
+     * Checks turtles can use IDetailProviders by getting details for a printed page.
+     */
+    @GameTest(timeoutTicks = COMPUTER_TIMEOUT)
+    fun Item_detail_provider(helper: GameTestHelper) = helper.sequence {
+        this
+            .thenComputerOk(marker = "initial")
+            .thenExecute {
+                // Register a dummy provider for printout items
+                ComputerCraftAPI.registerDetailProvider(
+                    ItemStack::class.java,
+                    object : BasicItemDetailProvider<ItemPrintout>("printout", ItemPrintout::class.java) {
+                        override fun provideDetails(data: MutableMap<in String, Any>, stack: ItemStack, item: ItemPrintout) {
+                            data["type"] = item.type.toString();
+                        }
+                    }
+                )
+            }
+            .thenComputerOk()
+    }
 }

src/testMod/java/dan200/computercraft/ingame/api/TestExtensions.kt

@@ -29,9 +29,11 @@ object Times {
  * Custom timeouts for various test types.
  */
 object Timeouts {
-    const val COMPUTER_TIMEOUT: Int = 200
+    private const val SECOND: Int = 20
 
-    const val CLIENT_TIMEOUT: Int = 400
+    const val COMPUTER_TIMEOUT: Int = SECOND * 15
+
+    const val CLIENT_TIMEOUT: Int = SECOND * 20
 }
 
 /**

src/testMod/java/dan200/computercraft/ingame/mod/Copier.java

@@ -6,6 +6,7 @@
 package dan200.computercraft.ingame.mod;
 
 import com.google.common.io.MoreFiles;
+import com.google.common.io.RecursiveDeleteOption;
 
 import java.io.IOException;
 import java.nio.file.FileVisitResult;
@@ -55,7 +56,7 @@ final class Copier extends SimpleFileVisitor<Path>
 
     public static void replicate( Path from, Path to, Predicate<Path> check ) throws IOException
     {
-        if( Files.exists( to ) ) MoreFiles.deleteRecursively( to );
+        if( Files.exists( to ) ) MoreFiles.deleteRecursively( to, RecursiveDeleteOption.ALLOW_INSECURE );
         Files.walkFileTree( from, new Copier( from, to, check ) );
     }
 }

src/testMod/server-files/computers/computer/0/startup.lua

@@ -4,6 +4,14 @@ if label == nil then return test.fail("Label a computer to use it.") end
 local fn, err = loadfile("tests/" .. label .. ".lua", nil, _ENV)
 if not fn then return test.fail(err) end
 
+local source = "@" .. label .. ".lua"
+debug.sethook(function()
+    local i = debug.getinfo(2, "lS")
+    if i.source == source and i.currentline then
+        test.log("At line " .. i.currentline)
+    end
+end, "l")
+
 local ok, err = pcall(fn)
 if not ok then return test.fail(err) end
 

src/testMod/server-files/computers/computer/0/tests/turtle_test.item_detail_provider.lua

@@ -0,0 +1,7 @@
+test.ok("initial")
+
+local details = turtle.getItemDetail(1, true)
+
+test.assert(details, "Has details")
+test.assert(details.printout, "Has printout meta")
+test.eq("PAGE", details.printout.type)

src/testMod/server-files/structures/turtle_test.item_detail_provider.snbt

@@ -0,0 +1,39 @@
+{
+    DataVersion: 2975,
+    size: [3, 3, 3],
+    data: [
+        {pos: [0, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [0, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [0, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [0, 1, 0], state: "minecraft:air"},
+        {pos: [0, 1, 1], state: "minecraft:air"},
+        {pos: [0, 1, 2], state: "minecraft:air"},
+        {pos: [1, 1, 0], state: "computercraft:turtle_normal{facing:south,waterlogged:false}", nbt: {ComputerId: 0, Fuel: 0, Items: [{Count: 1b, Slot: 0b, id: "computercraft:printed_page", tag: {Color0: "fffffffffffffffffffffffff", Color1: "fffffffffffffffffffffffff", Color10: "fffffffffffffffffffffffff", Color11: "fffffffffffffffffffffffff", Color12: "fffffffffffffffffffffffff", Color13: "fffffffffffffffffffffffff", Color14: "fffffffffffffffffffffffff", Color15: "fffffffffffffffffffffffff", Color16: "fffffffffffffffffffffffff", Color17: "fffffffffffffffffffffffff", Color18: "fffffffffffffffffffffffff", Color19: "fffffffffffffffffffffffff", Color2: "fffffffffffffffffffffffff", Color20: "fffffffffffffffffffffffff", Color3: "fffffffffffffffffffffffff", Color4: "fffffffffffffffffffffffff", Color5: "fffffffffffffffffffffffff", Color6: "fffffffffffffffffffffffff", Color7: "fffffffffffffffffffffffff", Color8: "fffffffffffffffffffffffff", Color9: "fffffffffffffffffffffffff", Pages: 1, Text0: "Example                  ", Text1: "                         ", Text10: "                         ", Text11: "                         ", Text12: "                         ", Text13: "                         ", Text14: "                         ", Text15: "                         ", Text16: "                         ", Text17: "                         ", Text18: "                         ", Text19: "                         ", Text2: "                         ", Text20: "                         ", Text3: "                         ", Text4: "                         ", Text5: "                         ", Text6: "                         ", Text7: "                         ", Text8: "                         ", Text9: "                         ", Title: "Example page"}}], Label: "turtle_test.item_detail_provider", On: 1b, Owner: {LowerId: -6876936588741668278L, Name: "Dev", UpperId: 4039158846114182220L}, Slot: 0, id: "computercraft:turtle_normal"}},
+        {pos: [1, 1, 1], state: "minecraft:air"},
+        {pos: [1, 1, 2], state: "minecraft:air"},
+        {pos: [2, 1, 0], state: "minecraft:air"},
+        {pos: [2, 1, 1], state: "minecraft:air"},
+        {pos: [2, 1, 2], state: "minecraft:air"},
+        {pos: [0, 2, 0], state: "minecraft:air"},
+        {pos: [0, 2, 1], state: "minecraft:air"},
+        {pos: [0, 2, 2], state: "minecraft:air"},
+        {pos: [1, 2, 0], state: "minecraft:air"},
+        {pos: [1, 2, 1], state: "minecraft:air"},
+        {pos: [1, 2, 2], state: "minecraft:air"},
+        {pos: [2, 2, 0], state: "minecraft:air"},
+        {pos: [2, 2, 1], state: "minecraft:air"},
+        {pos: [2, 2, 2], state: "minecraft:air"}
+    ],
+    entities: [],
+    palette: [
+        "minecraft:polished_andesite",
+        "minecraft:air",
+        "computercraft:turtle_normal{facing:south,waterlogged:false}"
+    ]
+}