Index: trunk/test/unit/org/openstreetmap/josm/gui/dialogs/layer/CycleLayerActionTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/gui/dialogs/layer/CycleLayerActionTest.java	(revision 15923)
+++ trunk/test/unit/org/openstreetmap/josm/gui/dialogs/layer/CycleLayerActionTest.java	(revision 15923)
@@ -0,0 +1,116 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.dialogs.layer;
+
+import static org.junit.Assert.assertEquals;
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.openstreetmap.josm.data.imagery.ImageryInfo;
+import org.openstreetmap.josm.data.imagery.ImageryLayerInfo;
+import org.openstreetmap.josm.data.osm.DataSet;
+import org.openstreetmap.josm.gui.MainApplication;
+import org.openstreetmap.josm.gui.layer.ImageryLayer;
+import org.openstreetmap.josm.gui.layer.MainLayerManager;
+import org.openstreetmap.josm.gui.layer.OsmDataLayer;
+import org.openstreetmap.josm.testutils.JOSMTestRules;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
+/**
+ * Test class for {@link CycleLayerDownAction}
+ *
+ * @author Taylor Smock
+ */
+public class CycleLayerActionTest {
+    /** Layers need a projection */
+    @Rule
+    @SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
+    public JOSMTestRules test = new JOSMTestRules().main().preferences().projection().fakeImagery();
+
+    private CycleLayerDownAction cycleDown;
+    private CycleLayerUpAction cycleUp;
+    private MainLayerManager manager;
+
+    /**
+     * Set up common items (make layers, etc.)
+     */
+    @Before
+    public void setUp() {
+        cycleDown = new CycleLayerDownAction();
+        cycleUp = new CycleLayerUpAction();
+        manager = MainApplication.getLayerManager();
+        for (int i = 0; i < 10; i++) {
+            manager.addLayer(new OsmDataLayer(new DataSet(), tr("Layer {0}", i), null));
+        }
+    }
+
+    /**
+     * Test going down from the bottom
+     */
+    @Test
+    public void testDownBottom() {
+        manager.setActiveLayer(manager.getLayers().get(0));
+        cycleDown.actionPerformed(null);
+        assertEquals(manager.getLayers().size() - 1, manager.getLayers().indexOf(manager.getActiveLayer()));
+    }
+
+    /**
+     * Check going up from the top
+     */
+    @Test
+    public void testUpTop() {
+        manager.setActiveLayer(manager.getLayers().get(manager.getLayers().size() - 1));
+        cycleUp.actionPerformed(null);
+        assertEquals(0, manager.getLayers().indexOf(manager.getActiveLayer()));
+    }
+
+    /**
+     * Check going down
+     */
+    @Test
+    public void testDown() {
+        manager.setActiveLayer(manager.getLayers().get(3));
+        cycleDown.actionPerformed(null);
+        assertEquals(2, manager.getLayers().indexOf(manager.getActiveLayer()));
+    }
+
+    /**
+     * Check going up
+     */
+    @Test
+    public void testUp() {
+        manager.setActiveLayer(manager.getLayers().get(3));
+        cycleUp.actionPerformed(null);
+        assertEquals(4, manager.getLayers().indexOf(manager.getActiveLayer()));
+    }
+
+    /**
+     * Test no layers
+     */
+    @Test
+    public void testNoLayers() {
+        manager.getLayers().forEach(manager::removeLayer);
+        cycleUp.actionPerformed(null);
+        cycleDown.actionPerformed(null);
+        assertEquals(0, manager.getLayers().size());
+    }
+
+    /**
+     * Test with an aerial imagery layer
+     */
+    @Test
+    public void testWithAerialImagery() {
+        final ImageryInfo magentaTilesInfo = ImageryLayerInfo.instance.getLayers().stream()
+                .filter(i -> i.getName().equals("Magenta Tiles")).findAny().get();
+        ImageryLayer imageryLayer = ImageryLayer.create(magentaTilesInfo);
+        manager.addLayer(imageryLayer);
+        manager.moveLayer(imageryLayer, 5);
+        manager.setActiveLayer(manager.getLayers().get(4));
+        cycleUp.actionPerformed(null);
+        assertEquals(6, manager.getLayers().indexOf(manager.getActiveLayer()));
+        cycleDown.actionPerformed(null);
+        assertEquals(4, manager.getLayers().indexOf(manager.getActiveLayer()));
+    }
+}