HDDS-1480. Add unit test

Signed-off-by: Rishabh Patel <ptlrshb@gmail.com>

hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/helpers/TestContainerUtils.java

@@ -46,6 +46,7 @@
 import static org.apache.hadoop.hdds.HddsUtils.processForDebug;
 import static org.apache.hadoop.ozone.container.ContainerTestHelper.getDummyCommandRequestProto;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
@@ -100,6 +101,13 @@ public void testDatanodeIDPersistent(@TempDir File tempDir) throws Exception {
       InetAddress mockedInetAddress = mock(InetAddress.class);
       mockedStaticInetAddress.when(() -> InetAddress.getByName(id1.getHostName()))
           .thenReturn(mockedInetAddress);
+
+      // If persisted ip address is different from resolved ip address,
+      // DatanodeDetails should be set with the resolved ip address
+      when(mockedInetAddress.getHostAddress())
+          .thenReturn("127.0.0.1");
+      assertWriteReadWithChangedIpAddress(tempDir, id1);
+
       when(mockedInetAddress.getHostAddress())
           .thenReturn(id1.getIpAddress());
 
@@ -146,6 +154,17 @@ private void assertWriteRead(@TempDir File tempDir,
     assertEquals(details.getCurrentVersion(), read.getCurrentVersion());
   }
 
+  private void assertWriteReadWithChangedIpAddress(@TempDir File tempDir,
+                                                   DatanodeDetails details) throws IOException {
+    // Write a single ID to the file and read it out
+    File file = new File(tempDir, "valid-values.id");
+    ContainerUtils.writeDatanodeDetailsTo(details, file, conf);
+
+    DatanodeDetails read = ContainerUtils.readDatanodeDetailsFrom(file);
+
+    assertNotEquals(details.toString(), read.toString());
+  }
+
   private void createMalformedIDFile(File malformedFile)
       throws IOException {
     DatanodeDetails id = randomDatanodeDetails();