Add some jqwik arbitraries for Minecraft types

This requires supporting registries in our platform test
code. Thankfully this is mostly the same as what we can do in Fabric -
the duplication is unfortunate - but it's easy enough.

projects/common/src/test/java/dan200/computercraft/TestPlatformHelper.java

@@ -21,6 +21,7 @@ import net.minecraft.commands.synchronization.ArgumentTypeInfo;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.core.Registry;
+import net.minecraft.core.registries.BuiltInRegistries;
 import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
@@ -50,6 +51,7 @@ import net.minecraft.world.phys.Vec3;
 
 import javax.annotation.Nullable;
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.List;
 import java.util.function.BiFunction;
 import java.util.function.Consumer;
@@ -68,30 +70,41 @@ public class TestPlatformHelper extends AbstractComputerCraftAPI implements Plat
         throw new UnsupportedOperationException("Cannot create config file inside tests");
     }
 
-    @Override
-    public <T> RegistryWrappers.RegistryWrapper<T> wrap(ResourceKey<Registry<T>> registry) {
-        throw new UnsupportedOperationException("Cannot query registry inside tests");
-    }
-
     @Override
     public <T> RegistrationHelper<T> createRegistrationHelper(ResourceKey<Registry<T>> registry) {
         throw new UnsupportedOperationException("Cannot query registry inside tests");
     }
 
-    @Override
-    public <K> ResourceLocation getRegistryKey(ResourceKey<Registry<K>> registry, K object) {
-        throw new UnsupportedOperationException("Cannot query registry inside tests");
+    @SuppressWarnings("unchecked")
+    private static <T> Registry<T> getRegistry(ResourceKey<Registry<T>> id) {
+        var registry = (Registry<T>) BuiltInRegistries.REGISTRY.get(id.location());
+        if (registry == null) throw new IllegalArgumentException("Unknown registry " + id);
+        return registry;
     }
 
     @Override
-    public <K> K getRegistryObject(ResourceKey<Registry<K>> registry, ResourceLocation id) {
-        throw new UnsupportedOperationException("Cannot query registry inside tests");
+    public <T> ResourceLocation getRegistryKey(ResourceKey<Registry<T>> registry, T object) {
+        var key = getRegistry(registry).getKey(object);
+        if (key == null) throw new IllegalArgumentException(object + " was not registered in " + registry);
+        return key;
+    }
+
+    @Override
+    public <T> T getRegistryObject(ResourceKey<Registry<T>> registry, ResourceLocation id) {
+        var value = getRegistry(registry).get(id);
+        if (value == null) throw new IllegalArgumentException(id + " was not registered in " + registry);
+        return value;
+    }
+
+    @Override
+    public <T> RegistryWrappers.RegistryWrapper<T> wrap(ResourceKey<Registry<T>> registry) {
+        return new RegistryWrapperImpl<>(registry.location(), getRegistry(registry));
     }
 
     @Nullable
     @Override
     public <T> T tryGetRegistryObject(ResourceKey<Registry<T>> registry, ResourceLocation id) {
-        throw new UnsupportedOperationException("Cannot query registries");
+        return getRegistry(registry).get(id);
     }
 
     @Override
@@ -239,4 +252,48 @@ public class TestPlatformHelper extends AbstractComputerCraftAPI implements Plat
     public String getInstalledVersion() {
         return "1.0";
     }
+
+    private record RegistryWrapperImpl<T>(
+        ResourceLocation name, Registry<T> registry
+    ) implements RegistryWrappers.RegistryWrapper<T> {
+        @Override
+        public int getId(T object) {
+            return registry.getId(object);
+        }
+
+        @Override
+        public ResourceLocation getKey(T object) {
+            var key = registry.getKey(object);
+            if (key == null) throw new IllegalArgumentException(object + " was not registered in " + name);
+            return key;
+        }
+
+        @Override
+        public T get(ResourceLocation location) {
+            var object = registry.get(location);
+            if (object == null) throw new IllegalArgumentException(location + " was not registered in " + name);
+            return object;
+        }
+
+        @Nullable
+        @Override
+        public T tryGet(ResourceLocation location) {
+            return registry.get(location);
+        }
+
+        @Override
+        public @Nullable T byId(int id) {
+            return registry.byId(id);
+        }
+
+        @Override
+        public int size() {
+            return registry.size();
+        }
+
+        @Override
+        public Iterator<T> iterator() {
+            return registry.iterator();
+        }
+    }
 }