add Pinger test

src/test/java/org/springstack/rsf/util/PingerTest.java

@@ -0,0 +1,37 @@
+package org.springstack.rsf.util;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Test;
+import org.springstack.rsf.RSFServer;
+
+public class PingerTest {
+
+    @Test
+    public void testCheckServerListAvaliable(){
+        List<RSFServer> servers = new ArrayList<RSFServer>();
+
+        RSFServer baidu = new RSFServer("baidu.com");
+        servers.add(baidu);
+        assertFalse(baidu.isAlive());
+
+        RSFServer example = new RSFServer("example.com");
+        servers.add(example);
+        assertFalse(example.isAlive());
+
+        RSFServer abs = new RSFServer("notfound.domain");
+        servers.add(abs);
+        assertFalse(abs.isAlive());
+
+        new Pinger(servers).runPinger();
+
+        assertTrue(baidu.isAlive());
+        assertTrue(example.isAlive());
+        assertFalse(abs.isAlive());
+    }
+}
+