2 files changed, 21 insertions, 2 deletions
diff --git a/src/test/java/org/traccar/helper/ChecksumTest.java b/src/test/java/org/traccar/helper/ChecksumTest.java
index 5737b9ff5..ff48527bc 100644
--- a/src/test/java/org/traccar/helper/ChecksumTest.java
+++ b/src/test/java/org/traccar/helper/ChecksumTest.java
@@ -4,6 +4,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import org.junit.Test;
 
+import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 
 import static org.junit.Assert.assertEquals;
@@ -36,4 +37,13 @@ public class ChecksumTest {
         assertEquals(0, Checksum.luhn(63070019470771L));
     }
 
+    @Test
+    public void testModulo256() {
+        assertEquals(0x00, Checksum.modulo256(ByteBuffer.wrap(new byte[] {0x00})));
+        assertEquals(0x00, Checksum.modulo256(ByteBuffer.wrap(new byte[] {0x00, 0x00, 0x00})));
+        assertEquals(0xca, Checksum.modulo256(ByteBuffer.wrap(new byte[] {0x77, 0x77, 0x77, 0x77, 0x77, 0x77})));
+
+
+    }
+
 }
diff --git a/src/test/java/org/traccar/helper/ServletHelperTest.java b/src/test/java/org/traccar/helper/ServletHelperTest.java
index 7359bf3dd..e419b6491 100644
--- a/src/test/java/org/traccar/helper/ServletHelperTest.java
+++ b/src/test/java/org/traccar/helper/ServletHelperTest.java
@@ -11,7 +11,7 @@ import static org.junit.Assert.assertEquals;
 public class ServletHelperTest {
 
     @Test
-    public void testIpBehindReverseProxy() {
+    public void testRetrieveRemoteAddressProxyMultiple() {
         MockRequest request = new MockRequest();
         request.setRemoteAddress("147.120.1.5");
         request.addHeader("X-FORWARDED-FOR", "231.23.45.65, 10.20.10.33, 10.20.20.34");
@@ -20,7 +20,16 @@ public class ServletHelperTest {
     }
 
     @Test
-    public void testNormalIp() {
+    public void testRetrieveRemoteAddressProxySingle() {
+        MockRequest request = new MockRequest();
+        request.setRemoteAddress("147.120.1.5");
+        request.addHeader("X-FORWARDED-FOR", "231.23.45.65");
+
+        assertEquals("231.23.45.65", ServletHelper.retrieveRemoteAddress(request));
+    }
+
+    @Test
+    public void testRetrieveRemoteAddressNoProxy() {
         MockRequest request = new MockRequest();
         request.setRemoteAddress("231.23.45.65");