Started NetherTreesListenerTest

I haven't worked that much on it yet. I've got tons of other things to do!

src/test/java/world/bentobox/bentobox/listeners/NetherTreesListenerTest.java

@@ -0,0 +1,47 @@
+package world.bentobox.bentobox.listeners;
+
+import org.junit.Before;
+import org.junit.runner.RunWith;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+import org.powermock.reflect.Whitebox;
+import world.bentobox.bentobox.BentoBox;
+import world.bentobox.bentobox.listeners.flags.NetherTreesListener;
+import world.bentobox.bentobox.managers.IslandWorldManager;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Tests {@link world.bentobox.bentobox.listeners.flags.NetherTreesListener}.
+ *
+ * @author Poslovitch
+ * @since 1.3.0
+ */
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({BentoBox.class})
+public class NetherTreesListenerTest {
+
+    /* Plugin */
+    private BentoBox plugin;
+
+    /* Island World Manager */
+    private IslandWorldManager iwm;
+
+    /* Listener */
+    private NetherTreesListener listener;
+
+    @Before
+    public void setUp() {
+        /* Plugin */
+        plugin = mock(BentoBox.class);
+        Whitebox.setInternalState(BentoBox.class, "instance", plugin);
+
+        /* Island World Manager */
+        iwm = mock(IslandWorldManager.class);
+        when(plugin.getIWM()).thenReturn(iwm);
+
+        /* Listener */
+        listener = new NetherTreesListener(plugin);
+    }
+}