Index: trunk/test/data/minimal.gpx
===================================================================
--- trunk/test/data/minimal.gpx	(revision 9719)
+++ trunk/test/data/minimal.gpx	(revision 9719)
@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
+<gpx xmlns="http://www.topografix.com/GPX/1/1" creator="MapSource 6.16.3" version="1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
+
+  <metadata>
+    <link href="http://www.garmin.com">
+      <text>Garmin International</text>
+    </link>
+    <time>2016-01-09T19:37:38Z</time>
+    <bounds maxlat="47.201499743387103" maxlon="8.798418799415231" minlat="47.18490038998425" minlon="8.77192972227931"/>
+  </metadata>
+
+  <wpt lat="47.192017380148172" lon="8.795854020863771">
+    <ele>480</ele>
+    <time>2016-01-09T19:29:38Z</time>
+    <name>Schranke</name>
+    <cmt>Pfad</cmt>
+    <desc>Pfad</desc>
+    <sym>Toll Booth</sym>
+    <extensions>
+      <gpxx:WaypointExtension xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3">
+        <gpxx:DisplayMode>SymbolAndName</gpxx:DisplayMode>
+      </gpxx:WaypointExtension>
+    </extensions>
+  </wpt>
+
+  <trk>
+    <name>2016-01-03 20:40:14</name>
+    <extensions>
+      <gpxx:TrackExtension xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3">
+        <gpxx:DisplayColor>Black</gpxx:DisplayColor>
+      </gpxx:TrackExtension>
+    </extensions>
+    <trkseg>
+      <trkpt lat="47.19286847859621" lon="8.79732714034617">
+        <ele>471.86000000000001</ele>
+        <time>2016-01-03T11:59:58Z</time>
+      </trkpt>
+      <trkpt lat="47.192921955138445" lon="8.797342479228973">
+        <ele>471.43000000000001</ele>
+        <time>2016-01-03T11:59:59Z</time>
+      </trkpt>
+      <trkpt lat="47.192975012585521" lon="8.797344239428639">
+        <ele>470.69</ele>
+        <time>2016-01-03T12:00:00Z</time>
+      </trkpt>
+    </trkseg>
+  </trk>
+
+</gpx>
Index: trunk/test/unit/org/openstreetmap/josm/gui/layer/gpx/DownloadWmsAlongTrackActionTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/gui/layer/gpx/DownloadWmsAlongTrackActionTest.java	(revision 9719)
+++ trunk/test/unit/org/openstreetmap/josm/gui/layer/gpx/DownloadWmsAlongTrackActionTest.java	(revision 9719)
@@ -0,0 +1,65 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.layer.gpx;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.openstreetmap.josm.JOSMFixture;
+import org.openstreetmap.josm.Main;
+import org.openstreetmap.josm.TestUtils;
+import org.openstreetmap.josm.data.gpx.GpxData;
+import org.openstreetmap.josm.data.imagery.ImageryInfo;
+import org.openstreetmap.josm.gui.layer.TMSLayer;
+import org.openstreetmap.josm.gui.layer.gpx.DownloadWmsAlongTrackAction.PrecacheWmsTask;
+import org.openstreetmap.josm.io.GpxReaderTest;
+
+/**
+ * Unit tests of {@link DownloadWmsAlongTrackAction} class.
+ */
+public class DownloadWmsAlongTrackActionTest {
+
+    /**
+     * Setup test.
+     */
+    @BeforeClass
+    public static void setUpBeforeClass() {
+        JOSMFixture.createUnitTestFixture().init(true);
+    }
+
+    /**
+     * Test action without layer.
+     */
+    @Test
+    public void testNoLayer() {
+        assertNull(new DownloadWmsAlongTrackAction(new GpxData()).createTask());
+    }
+
+    /**
+     * Test action with a TMS layer.
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testTmsLayer() throws Exception {
+        // Create new TMS layer and clear cache
+        TMSLayer layer = new TMSLayer(new ImageryInfo("OSM TMS", "https://a.tile.openstreetmap.org/{zoom}/{x}/{y}.png", "tms", null, null));
+        try {
+            Main.main.addLayer(layer);
+            TMSLayer.getCache().clear();
+            assertTrue(TMSLayer.getCache().getMatching(".*").isEmpty());
+            // Perform action
+            final GpxData gpx = GpxReaderTest.parseGpxData(TestUtils.getTestDataRoot() + "minimal.gpx");
+            PrecacheWmsTask task = new DownloadWmsAlongTrackAction(gpx).createTask();
+            assertNotNull(task);
+            task.run();
+            // Ensure cache is not empty
+            assertFalse(TMSLayer.getCache().getMatching(".*").isEmpty());
+        } finally {
+            // Ensure we clean the place before leaving, even if test fails.
+            Main.main.removeLayer(layer);
+        }
+    }
+}