Index: trunk/test/unit/org/openstreetmap/josm/gui/preferences/imagery/ImageryPreferenceTestIT.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/gui/preferences/imagery/ImageryPreferenceTestIT.java	(revision 14482)
+++ trunk/test/unit/org/openstreetmap/josm/gui/preferences/imagery/ImageryPreferenceTestIT.java	(revision 14482)
@@ -0,0 +1,101 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.preferences.imagery;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+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.testutils.JOSMTestRules;
+import org.openstreetmap.josm.tools.HttpClient;
+import org.openstreetmap.josm.tools.HttpClient.Response;
+import org.openstreetmap.josm.tools.Logging;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
+/**
+ * Integration tests of {@link ImageryPreference} class.
+ */
+public class ImageryPreferenceTestIT {
+
+    /**
+     * Setup rule
+     */
+    @Rule
+    @SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
+    public JOSMTestRules test = new JOSMTestRules().https().timeout(10000*60);
+
+    private final Map<ImageryInfo, List<String>> errors = Collections.synchronizedMap(new HashMap<>());
+    private final Set<URL> workingURLs = Collections.synchronizedSet(new HashSet<>());
+
+    private boolean addError(ImageryInfo info, String error) {
+        return errors.computeIfAbsent(info, x -> new ArrayList<>()).add(error);
+    }
+
+    private void checkUrl(ImageryInfo info, String url) {
+        if (url != null) {
+            try {
+                checkUrl(info, new URL(url));
+            } catch (MalformedURLException e) {
+                addError(info, url + " -> " + e.getMessage());
+            }
+        }
+    }
+
+    private void checkUrl(ImageryInfo info, URL url) {
+        if (url != null && !workingURLs.contains(url)) {
+            try {
+                Response response = HttpClient.create(url).connect();
+                if (response.getResponseCode() >= 400) {
+                    addError(info, url.toExternalForm() + " -> HTTP " + response.getResponseCode());
+                } else {
+                    workingURLs.add(url);
+                }
+                response.disconnect();
+            } catch (IOException e) {
+                addError(info, url + " -> " + e.getMessage());
+            }
+        }
+    }
+
+    private void checkEntry(ImageryInfo info) {
+        Logging.info("Checking "+ info);
+
+        if (info.getAttributionImageRaw() != null && info.getAttributionImage() == null) {
+            addError(info, "Can't fetch attribution image: " + info.getAttributionImageRaw());
+        }
+
+        checkUrl(info, info.getAttributionImageURL());
+        checkUrl(info, info.getAttributionLinkURL());
+        checkUrl(info, info.getEulaAcceptanceRequired());
+        checkUrl(info, info.getPermissionReferenceURL());
+        checkUrl(info, info.getTermsOfUseURL());
+
+        for (ImageryInfo mirror : info.getMirrors()) {
+            checkEntry(mirror);
+        }
+    }
+
+    /**
+     * Test that available imagery entries are valid.
+     * @throws Exception in case of error
+     */
+    @Test
+    public void testValidityOfAvailableImageryEntries() throws Exception {
+        ImageryLayerInfo.instance.load(false);
+        ImageryLayerInfo.instance.getDefaultLayers().parallelStream().forEach(this::checkEntry);
+        assertTrue(errors.toString(), errors.isEmpty());
+    }
+}