diff --git a/remote-api/src/test/java/org/alfresco/rest/api/impl/SizeDetailsImplTest.java b/remote-api/src/test/java/org/alfresco/rest/api/impl/SizeDetailsImplTest.java
new file mode 100644
index 0000000000..987d97702f
--- /dev/null
+++ b/remote-api/src/test/java/org/alfresco/rest/api/impl/SizeDetailsImplTest.java
@@ -0,0 +1,109 @@
+/*
+ * #%L
+ * Alfresco Remote API
+ * %%
+ * Copyright (C) 2005 - 2024 Alfresco Software Limited
+ * %%
+ * This file is part of the Alfresco software.
+ * If the software was purchased under a paid Alfresco license, the terms of
+ * the paid license agreement will prevail.  Otherwise, the software is
+ * provided under the following open source license terms:
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ * #L%
+ */
+package org.alfresco.rest.api.impl;
+
+import org.alfresco.repo.action.executer.NodeSizeDetailsActionExecutor;
+import org.alfresco.repo.cache.SimpleCache;
+import org.alfresco.rest.api.Nodes;
+import org.alfresco.rest.api.model.Node;
+import org.alfresco.rest.api.model.NodeSizeDetails;
+import org.alfresco.service.cmr.action.Action;
+import org.alfresco.service.cmr.action.ActionService;
+import org.alfresco.service.cmr.repository.NodeRef;
+import org.alfresco.service.cmr.repository.NodeService;
+import org.alfresco.service.cmr.security.PermissionService;
+import org.alfresco.service.namespace.QName;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.Serializable;
+import java.util.Map;
+
+import static org.junit.Assert.assertNull;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Unit tests for {@link SizeDetailsImpl} class.
+ *
+ */
+public class SizeDetailsImplTest
+{
+    private final static int DEFAULT_ITEMS = 1000;
+    private SizeDetailsImpl sizeDetailsImpl;
+    private Nodes nodes;
+    private NodeService nodeService;
+    private ActionService actionService;
+    private SimpleCache<Serializable, Map<String, Object>> simpleCache;
+    private Action action;
+    private static final String NAMESPACE = "http://www.alfresco.org/test/NodeSizeDetailsTest";
+    private static final QName TYPE_FOLDER = QName.createQName(NAMESPACE, "folder");
+
+    @Before
+    public void setUp()
+    {
+        sizeDetailsImpl = new SizeDetailsImpl();
+        nodes = mock(Nodes.class);
+        nodeService = mock(NodeService.class);
+        PermissionService permissionService = mock(PermissionService.class);
+        actionService = mock(ActionService.class);
+        action = mock(Action.class);
+        simpleCache  = mock(SimpleCache.class);
+
+        sizeDetailsImpl.setNodes(nodes);
+        sizeDetailsImpl.setNodeService(nodeService);
+        sizeDetailsImpl.setPermissionService(permissionService);
+        sizeDetailsImpl.setActionService(actionService);
+        sizeDetailsImpl.setSimpleCache(simpleCache);
+        sizeDetailsImpl.setDefaultItems(DEFAULT_ITEMS);
+    }
+
+    @Test
+    public void calculateNodeSize()
+    {
+        String nodeName = "folderNode";
+        String nodeId = "node-id";
+        NodeRef nodeRef = new NodeRef("protocol", "identifier", nodeId);
+        action.setTrackStatus(true);
+        action.setExecuteAsynchronously(true);
+        action.setParameterValue(NodeSizeDetailsActionExecutor.DEFAULT_SIZE, DEFAULT_ITEMS);
+
+        Node node = new Node();
+        node.setIsFolder(true);
+        node.setNodeRef(nodeRef);
+        node.setName(nodeName);
+        node.setNodeType(TYPE_FOLDER.getLocalName());
+        node.setNodeId(nodeRef.getId());
+
+        when(nodes.validateNode(nodeId)).thenReturn(nodeRef);
+        when(nodes.getNode(nodeId)).thenReturn(node);
+        when(nodeService.getType(nodeRef)).thenReturn(TYPE_FOLDER);
+        when(actionService.createAction(NodeSizeDetailsActionExecutor.NAME)).thenReturn(action);
+        NodeSizeDetails nodeSizeDetails = sizeDetailsImpl.calculateNodeSize(nodeId);
+        assertNull("After executing POST/request-size-details first time, it will provide null with 202 status code",nodeSizeDetails);
+    }
+
+}