Added test class.

src/main/java/world/bentobox/bentobox/hooks/ItemsAdderHook.java

@@ -38,6 +38,12 @@ public class ItemsAdderHook extends Hook {
 
     private BentoBox plugin;
 
+    private BlockInteractListener listener;
+
+    /**
+     * Register the hook
+     * @param plugin BentoBox
+     */
     public ItemsAdderHook(BentoBox plugin) {
         super("ItemsAdder", Material.NETHER_STAR);
         this.plugin = plugin;
@@ -50,14 +56,17 @@ public boolean hook() {
             return false;
         }
         // Register listener
-        Bukkit.getPluginManager().registerEvents(new BlockInteractListener(), plugin);
+        listener = new BlockInteractListener();
+        Bukkit.getPluginManager().registerEvents(listener, plugin);
         plugin.getFlagsManager().registerFlag(ITEMS_ADDER_EXPLOSIONS);
         return true;
     }
 
-    @Override
-    public String getFailureCause() {
-        return ""; // No errors
+    /**
+     * @return the listener
+     */
+    protected BlockInteractListener getListener() {
+        return listener;
     }
 
     /**
@@ -70,6 +79,10 @@ public void clearBlockInfo(Location location) {
 
     class BlockInteractListener extends FlagListener {
 
+        /**
+         * Handles explosions of ItemAdder items
+         * @param event explosion event
+         */
         @EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
         public void onExplosion(EntityExplodeEvent event)
         {

src/test/java/world/bentobox/bentobox/hooks/ItemsAdderHookTest.java

@@ -0,0 +1,218 @@
+package world.bentobox.bentobox.hooks;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.UUID;
+
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.Material;
+import org.bukkit.World;
+import org.bukkit.block.Block;
+import org.bukkit.entity.EntityType;
+import org.bukkit.entity.Player;
+import org.bukkit.event.entity.EntityExplodeEvent;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.plugin.PluginManager;
+import org.eclipse.jdt.annotation.Nullable;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.stubbing.Answer;
+import org.powermock.api.mockito.PowerMockito;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+import org.powermock.reflect.Whitebox;
+
+import dev.lone.itemsadder.api.CustomBlock;
+import world.bentobox.bentobox.BentoBox;
+import world.bentobox.bentobox.api.user.Notifier;
+import world.bentobox.bentobox.api.user.User;
+import world.bentobox.bentobox.database.objects.Island;
+import world.bentobox.bentobox.database.objects.Players;
+import world.bentobox.bentobox.hooks.ItemsAdderHook.BlockInteractListener;
+import world.bentobox.bentobox.managers.FlagsManager;
+import world.bentobox.bentobox.managers.IslandWorldManager;
+import world.bentobox.bentobox.managers.IslandsManager;
+import world.bentobox.bentobox.managers.LocalesManager;
+import world.bentobox.bentobox.managers.PlaceholdersManager;
+import world.bentobox.bentobox.managers.PlayersManager;
+
+/**
+ * Test class for ItemsAdder hook
+ */
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({ BentoBox.class, Bukkit.class, CustomBlock.class })
+public class ItemsAdderHookTest {
+
+    @Mock
+    private BentoBox plugin;
+    private ItemsAdderHook hook;
+    @Mock
+    private PluginManager pim;
+    @Mock
+    private Plugin itemsAdder;
+    @Mock
+    private FlagsManager fm;
+    @Mock
+    private Location location;
+    @Mock
+    private Player entity;
+    @Mock
+    private IslandWorldManager iwm;
+    @Mock
+    private World world;
+    @Mock
+    private IslandsManager im;
+    @Mock
+    private Island island;
+    @Mock
+    private PlayersManager pm;
+    @Mock
+    private PlaceholdersManager phm;
+    @Mock
+    private Notifier notifier;
+
+    /**
+     * @throws java.lang.Exception
+     */
+    @Before
+    public void setUp() throws Exception {
+        // Set up plugin
+        plugin = mock(BentoBox.class);
+        Whitebox.setInternalState(BentoBox.class, "instance", plugin);
+
+        // User
+        UUID uuid = UUID.randomUUID();
+        when(entity.getUniqueId()).thenReturn(uuid);
+        User.setPlugin(plugin);
+        User.getInstance(entity);
+
+        // Flags Manager
+        when(plugin.getFlagsManager()).thenReturn(fm);
+
+        // Bukkit
+        PowerMockito.mockStatic(Bukkit.class, Mockito.RETURNS_MOCKS);
+        when(Bukkit.getPluginManager()).thenReturn(pim);
+        when(pim.getPlugin("ItemsAdder")).thenReturn(itemsAdder);
+
+        // IWM
+        when(plugin.getIWM()).thenReturn(iwm);
+        when(iwm.inWorld(location)).thenReturn(true);
+
+        // CustomBlock
+        PowerMockito.mockStatic(CustomBlock.class, Mockito.RETURNS_MOCKS);
+
+        // Location
+        when(world.getName()).thenReturn("bskyblock");
+        when(location.getWorld()).thenReturn(world);
+
+        // Island manager
+        when(plugin.getIslands()).thenReturn(im);
+
+        when(im.getProtectedIslandAt(location)).thenReturn(Optional.of(island));
+
+        // Players Manager
+        when(plugin.getPlayers()).thenReturn(pm);
+        @Nullable
+        Players playerObject = new Players();
+        playerObject.setUniqueId(uuid.toString());
+        when(pm.getPlayer(uuid)).thenReturn(playerObject);
+
+        // Locales
+        LocalesManager lm = mock(LocalesManager.class);
+        when(lm.get(any(), any())).thenAnswer((Answer<String>) invocation -> invocation.getArgument(1, String.class));
+        when(plugin.getLocalesManager()).thenReturn(lm);
+
+        // Return the same string
+        when(phm.replacePlaceholders(any(), anyString()))
+                .thenAnswer((Answer<String>) invocation -> invocation.getArgument(1, String.class));
+        when(plugin.getPlaceholdersManager()).thenReturn(phm);
+
+        // Notifier
+        when(plugin.getNotifier()).thenReturn(notifier);
+
+        hook = new ItemsAdderHook(plugin);
+    }
+
+    /**
+     * @throws java.lang.Exception
+     */
+    @After
+    public void tearDown() throws Exception {
+        User.clearUsers();
+    }
+
+    /**
+     * Test method for {@link world.bentobox.bentobox.hooks.ItemsAdderHook#hook()}.
+     */
+    @Test
+    public void testHook() {
+        assertTrue(hook.hook());
+        verify(pim).registerEvents(hook.getListener(), plugin);
+        verify(fm).registerFlag(ItemsAdderHook.ITEMS_ADDER_EXPLOSIONS);
+    }
+
+    /**
+     * Test method for {@link world.bentobox.bentobox.hooks.ItemsAdderHook#hook()}.
+     */
+    @Test
+    public void testHookFail() {
+        // No plugin
+        when(pim.getPlugin("ItemsAdder")).thenReturn(null);
+        assertFalse(hook.hook());
+        verify(pim, never()).registerEvents(any(), any());
+        verify(fm, never()).registerFlag(any());
+    }
+
+    /**
+     * Test method for {@link world.bentobox.bentobox.hooks.ItemsAdderHook.BlockInteractListener#onExplosion(EntityExplodeEvent)}
+     */
+    @Test
+    public void testListener() {
+        // Make listener
+        assertTrue(hook.hook());
+        BlockInteractListener listener = hook.getListener();
+        when(entity.getType()).thenReturn(EntityType.PLAYER);
+        when(entity.hasPermission("XXXXXX")).thenReturn(true);
+        List<Block> list = new ArrayList<>();
+        EntityExplodeEvent event = new EntityExplodeEvent(entity, location, list, 0);
+        listener.onExplosion(event);
+        assertTrue(event.isCancelled());
+    }
+
+    /**
+     * Test method for {@link world.bentobox.bentobox.hooks.ItemsAdderHook#ItemsAdderHook(world.bentobox.bentobox.BentoBox)}.
+     */
+    @Test
+    public void testItemsAdderHook() {
+        assertNotNull(hook);
+        assertEquals(Material.NETHER_STAR, hook.getIcon());
+    }
+
+    /**
+     * Test method for {@link world.bentobox.bentobox.hooks.ItemsAdderHook#clearBlockInfo(org.bukkit.Location)}.
+     */
+    @Test
+    public void testClearBlockInfo() {
+        hook.clearBlockInfo(location);
+        PowerMockito.verifyStatic(CustomBlock.class);
+        CustomBlock.remove(location);
+    }
+
+}