Add testing for registry lists

Towny/pom.xml

@@ -252,6 +252,12 @@
             <version>21.3</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.github.seeseemelk</groupId>
+            <artifactId>MockBukkit-v1.20</artifactId>
+            <version>3.17.0</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
     <pluginRepositories>
         <pluginRepository>

Towny/src/main/java/com/palmergames/bukkit/towny/object/AbstractRegistryList.java

@@ -8,6 +8,7 @@
 import org.bukkit.Registry;
 import org.bukkit.Tag;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.VisibleForTesting;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Locale;
@@ -45,6 +46,11 @@ public boolean contains(@NotNull String element) {
 		final T matched = BukkitTools.matchRegistry(this.registry, element);
 		return matched != null && this.contains(matched);
 	}
+
+	@VisibleForTesting
+	public Collection<T> tagged() {
+		return this.tagged;
+	}
 
 	@SuppressWarnings("unused")
 	public static class Builder<T extends Keyed, F extends AbstractRegistryList<T>> {

Towny/src/test/java/com/palmergames/bukkit/towny/test/RegistryListTests.java

@@ -0,0 +1,22 @@
+package com.palmergames.bukkit.towny.test;
+
+import be.seeseemelk.mockbukkit.MockBukkit;
+import com.palmergames.bukkit.util.ItemLists;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class RegistryListTests {
+
+	@BeforeAll
+	static void mock() {
+		MockBukkit.mock();
+	}
+
+	@Test
+	void testListAdd() {
+		ItemLists itemList = ItemLists.newBuilder().add("stone").build();
+		assertEquals(1, itemList.tagged().size());
+	}
+}