Avoid UnknownHostException in WalkEncryptionTest

Prevent that WalkEncryptionTest fails when it can't determine the public
IP address using http://checkip.amazonws.com. Also set timeouts when
determining IP address in order to prevent long wait times during tests.

Change-Id: I1d2fe09f99df2a5f75f8077811a72fb2271cdddb
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/WalkEncryptionTest.java

@@ -43,6 +43,20 @@
 
 package org.eclipse.jgit.transport;
 
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.UTF_8;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.cryptoCipherListPBE;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.cryptoCipherListTrans;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.folderDelete;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.permitLongTests;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.policySetup;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.product;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.proxySetup;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.publicAddress;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.reportPolicy;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.securityProviderName;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.textWrite;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.transferStream;
+import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.verifyFileContent;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -59,7 +73,10 @@ import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.PrintWriter;
+import java.net.SocketTimeoutException;
 import java.net.URL;
+import java.net.URLConnection;
+import java.net.UnknownHostException;
 import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.security.GeneralSecurityException;
@@ -94,8 +111,6 @@ import org.junit.runners.Suite;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import static org.eclipse.jgit.transport.WalkEncryptionTest.Util.*;
-
 /**
  * Amazon S3 encryption pipeline test.
  *
@@ -401,14 +416,22 @@ public class WalkEncryptionTest {
 		 * @throws Exception
 		 */
 		static String publicAddress() throws Exception {
-			String service = "http://checkip.amazonaws.com";
-			URL url = new URL(service);
-			BufferedReader reader = new BufferedReader(
-					new InputStreamReader(url.openStream()));
 			try {
-				return reader.readLine();
-			} finally {
-				reader.close();
+				String service = "http://checkip.amazonaws.com";
+				URL url = new URL(service);
+				URLConnection c = url.openConnection();
+				c.setConnectTimeout(500);
+				c.setReadTimeout(500);
+				BufferedReader reader = new BufferedReader(
+						new InputStreamReader(c.getInputStream()));
+				try {
+					return reader.readLine();
+				} finally {
+					reader.close();
+				}
+			} catch (UnknownHostException | SocketTimeoutException e) {
+				return "Can't reach http://checkip.amazonaws.com to"
+						+ " determine public address";
 			}
 		}