Index: /trunk/src/org/openstreetmap/josm/actions/downloadtasks/DownloadGpsTask.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/actions/downloadtasks/DownloadGpsTask.java	(revision 8903)
+++ /trunk/src/org/openstreetmap/josm/actions/downloadtasks/DownloadGpsTask.java	(revision 8904)
@@ -146,9 +146,13 @@
             if (layer == null) return null;
             if (newLayer || mergeLayer == null) {
-                Main.main.addLayer(layer);
+                if (Main.main != null) {
+                    Main.main.addLayer(layer);
+                }
                 return layer;
             } else {
                 mergeLayer.mergeFrom(layer);
-                Main.map.repaint();
+                if (Main.map != null) {
+                    Main.map.repaint();
+                }
                 return mergeLayer;
             }
@@ -179,5 +183,6 @@
         }
 
-        @Override protected void cancel() {
+        @Override
+        protected void cancel() {
             setCanceled(true);
             if (reader != null) {
Index: /trunk/test/unit/org/openstreetmap/josm/actions/downloadtasks/DownloadGpsTaskTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/actions/downloadtasks/DownloadGpsTaskTest.java	(revision 8904)
+++ /trunk/test/unit/org/openstreetmap/josm/actions/downloadtasks/DownloadGpsTaskTest.java	(revision 8904)
@@ -0,0 +1,54 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.actions.downloadtasks;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.concurrent.ExecutionException;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.openstreetmap.josm.JOSMFixture;
+
+/**
+ * Unit tests for class {@link DownloadGpsTask}.
+ */
+public class DownloadGpsTaskTest {
+
+    private static final String REMOTE_FILE = "https://josm.openstreetmap.de/export/head/josm/trunk/data_nodist/munich.gpx";
+
+    /**
+     * Setup test.
+     */
+    @BeforeClass
+    public static void setUp() {
+        JOSMFixture.createUnitTestFixture().init();
+    }
+
+    /**
+     * Unit test of {@code DownloadGpsTask#acceptsUrl} method.
+     */
+    @Test
+    public void testAcceptsURL() {
+        DownloadGpsTask task = new DownloadGpsTask();
+        assertFalse(task.acceptsUrl(null));
+        assertFalse(task.acceptsUrl(""));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/trackpoints?bbox=0,51.5,0.25,51.75"));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/trackpoints?bbox=0,51.5,0.25,51.75&page=0"));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/trace/5000/data"));
+        assertTrue(task.acceptsUrl("http://www.openstreetmap.org/trace/5000/data"));
+        assertTrue(task.acceptsUrl("http://www.trackmyjourney.co.uk/exportgpx.php?session=S6rZR2Bh6GwX1wpB0C&trk=79292"));
+        assertTrue(task.acceptsUrl(REMOTE_FILE));
+    }
+
+    /**
+     * Unit test of {@code DownloadGpsTask#loadUrl} method with an external file.
+     * @throws ExecutionException if the computation threw an exception
+     * @throws InterruptedException if the current thread was interrupted while waiting
+     */
+    @Test
+    public void testDownloadExternalFile() throws InterruptedException, ExecutionException {
+        DownloadGpsTask task = new DownloadGpsTask();
+        task.loadUrl(false, REMOTE_FILE, null).get();
+    }
+}
Index: /trunk/test/unit/org/openstreetmap/josm/actions/downloadtasks/DownloadOsmTaskTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/actions/downloadtasks/DownloadOsmTaskTest.java	(revision 8904)
+++ /trunk/test/unit/org/openstreetmap/josm/actions/downloadtasks/DownloadOsmTaskTest.java	(revision 8904)
@@ -0,0 +1,55 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.actions.downloadtasks;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.concurrent.ExecutionException;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.openstreetmap.josm.JOSMFixture;
+
+/**
+ * Unit tests for class {@link DownloadOsmTask}.
+ */
+public class DownloadOsmTaskTest {
+
+    private static final String REMOTE_FILE = "https://josm.openstreetmap.de/export/head/josm/trunk/data_nodist/direction-arrows.osm";
+
+    /**
+     * Setup test.
+     */
+    @BeforeClass
+    public static void setUp() {
+        JOSMFixture.createUnitTestFixture().init();
+    }
+
+    /**
+     * Unit test of {@code DownloadOsmTask#acceptsUrl} method.
+     */
+    @Test
+    public void testAcceptsURL() {
+        DownloadOsmTask task = new DownloadOsmTask();
+        assertFalse(task.acceptsUrl(null));
+        assertFalse(task.acceptsUrl(""));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/node/100"));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/way/100"));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/relation/100"));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/nodes?nodes=101,102,103"));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/ways?ways=101,102,103"));
+        assertTrue(task.acceptsUrl("http://api.openstreetmap.org/api/0.6/relations?relations=101,102,103"));
+        assertTrue(task.acceptsUrl(REMOTE_FILE));
+    }
+
+    /**
+     * Unit test of {@code DownloadOsmTask#loadUrl} method with an external file.
+     * @throws ExecutionException if the computation threw an exception
+     * @throws InterruptedException if the current thread was interrupted while waiting
+     */
+    @Test
+    public void testDownloadExternalFile() throws InterruptedException, ExecutionException {
+        DownloadOsmTask task = new DownloadOsmTask();
+        task.loadUrl(false, REMOTE_FILE, null).get();
+    }
+}