deviceOrg: get Roots dao fix

components/device-mgt-extensions/io.entgra.device.mgt.core.device.mgt.extensions.device.organization/src/main/java/io/entgra/device/mgt/core/device/mgt/extensions/device/organization/dao/impl/DeviceOrganizationDAOImpl.java

@@ -323,8 +323,13 @@ public class DeviceOrganizationDAOImpl implements DeviceOrganizationDAO {
         List<DeviceOrganization> deviceOrganizations = new ArrayList<>();
         try {
             Connection conn = ConnectionManagerUtil.getDBConnection();
-            String sql = "SELECT * FROM DM_DEVICE_ORGANIZATION WHERE PARENT_DEVICE_ID IS NULL " +
+            String sql = "SELECT * FROM DM_DEVICE_ORGANIZATION " +
+                    "WHERE (PARENT_DEVICE_ID IS NULL AND " +
+                    "DEVICE_ID NOT IN " +
+                    "(SELECT DEVICE_ID FROM DM_DEVICE_ORGANIZATION " +
+                    "WHERE PARENT_DEVICE_ID IS NOT NULL)) " +
                     "LIMIT ? OFFSET ?";
+
             try (PreparedStatement stmt = conn.prepareStatement(sql)) {
                 stmt.setInt(1, request.getLimit());
                 stmt.setInt(2, request.getOffSet());

components/device-mgt-extensions/io.entgra.device.mgt.core.device.mgt.extensions.device.organization/src/test/java/io/entgra/device/mgt/core/device/mgt/extensions/device/organization/ServiceTest.java

@@ -148,7 +148,7 @@ public class ServiceTest extends BaseDeviceOrganizationTest {
 
         // Define specific combinations of deviceID and parentDeviceID
         int[][] combinations = {
-                {20, 19}, {19, 18}, {18, 17}, {20, 5}, {20, 17}, {19, 16}, {17, 16}, {16, 17}
+                {20, 19}, {19, 18}, {18, 17}, {20, 5}, {20, 17}, {19, 16}, {17, 16}, {16, 17}, {2, 1}
                 // Add more combinations as needed
         };
 
@@ -175,6 +175,17 @@ public class ServiceTest extends BaseDeviceOrganizationTest {
             iterationCount++;
         }
 
+        DeviceOrganization nullParent = new DeviceOrganization();
+        nullParent.setDeviceId(1);
+        nullParent.setParentDeviceId(null);
+        boolean isNullParentAdded = deviceOrganizationService.addDeviceOrganization(nullParent);
+
+        DeviceOrganization secondNullParent = new DeviceOrganization();
+        secondNullParent.setDeviceId(2);
+        secondNullParent.setParentDeviceId(null);
+        boolean isSecondNullParentAdded = deviceOrganizationService.addDeviceOrganization(secondNullParent);
+
+
         // Optionally, you can assert that the correct number of organizations were inserted
         Assert.assertEquals(organizationCount, combinations.length, "Inserted organizations count mismatch");
     }
@@ -270,6 +281,23 @@ public class ServiceTest extends BaseDeviceOrganizationTest {
         Assert.assertFalse(organizations.isEmpty(), "List of organizations should not be empty");
     }
 
+    @Test(dependsOnMethods = "testAddMultipleDeviceOrganizations")
+    public void testGetMultipleRootOrganizations() throws DeviceOrganizationMgtPluginException {
+        int offset = 0;
+        int limit = 10;
+        PaginationRequest request = new PaginationRequest(offset, limit);
+        List<DeviceOrganization> organizations = deviceOrganizationService.getDeviceOrganizationRoots(request);
+        for (DeviceOrganization organization : organizations) {
+            log.info("organizationID = " + organization.getOrganizationId());
+            log.info("deviceID = " + organization.getDeviceId());
+            log.info("parentDeviceID = " + organization.getParentDeviceId());
+            log.info("updateTime = " + organization.getUpdateTime());
+            log.info("----------------------------------------------");
+        }
+        Assert.assertNotNull(organizations, "List of organizations cannot be null");
+        Assert.assertFalse(organizations.isEmpty(), "List of organizations should not be empty");
+    }
+
     @Test(dependsOnMethods = "testAddDeviceOrganizationWithNullParent")
     public void testGetLeafOrganizationsWithNullParents() throws DeviceOrganizationMgtPluginException {
         int offset = 0;