diff --git a/test/functional/services/monaco_editor.ts b/test/functional/services/monaco_editor.ts
index 245a4eef2a549..43ce38aa2c787 100644
--- a/test/functional/services/monaco_editor.ts
+++ b/test/functional/services/monaco_editor.ts
@@ -8,6 +8,7 @@
  */
 
 import { type monaco } from '@kbn/monaco';
+import expect from '@kbn/expect';
 import { FtrService } from '../ftr_provider_context';
 
 export class MonacoEditorService extends FtrService {
@@ -62,6 +63,11 @@ export class MonacoEditorService extends FtrService {
         value
       );
     });
+    const newCodeEditorValue = await this.getCodeEditorValue(nthIndex);
+    expect(newCodeEditorValue).equal(
+      value,
+      `Expected value was: ${value}, but got: ${newCodeEditorValue}`
+    );
   }
 
   public async getCurrentMarkers(testSubjId: string) {
diff --git a/x-pack/plugins/painless_lab/public/application/components/request_flyout.tsx b/x-pack/plugins/painless_lab/public/application/components/request_flyout.tsx
index 3874c00416e3b..58e363bbd7e58 100644
--- a/x-pack/plugins/painless_lab/public/application/components/request_flyout.tsx
+++ b/x-pack/plugins/painless_lab/public/application/components/request_flyout.tsx
@@ -74,7 +74,12 @@ export const RequestFlyout: FunctionComponent<Props> = ({
               id: 'request',
               name: 'Request',
               content: (
-                <EuiCodeBlock language="json" paddingSize="s" isCopyable>
+                <EuiCodeBlock
+                  language="json"
+                  paddingSize="s"
+                  data-test-subj="painlessLabFlyoutRequest"
+                  isCopyable
+                >
                   {'POST _scripts/painless/_execute\n'}
                   {requestBody}
                 </EuiCodeBlock>
@@ -84,7 +89,12 @@ export const RequestFlyout: FunctionComponent<Props> = ({
               id: 'response',
               name: 'Response',
               content: (
-                <EuiCodeBlock language="json" paddingSize="s" isCopyable>
+                <EuiCodeBlock
+                  language="json"
+                  paddingSize="s"
+                  data-test-subj="painlessLabFlyoutResponse"
+                  isCopyable
+                >
                   {response}
                 </EuiCodeBlock>
               ),
diff --git a/x-pack/test/functional/apps/painless_lab/painless_lab_flyout.ts b/x-pack/test/functional/apps/painless_lab/painless_lab_flyout.ts
index 2f03212c72581..f16b0dfa6f4c3 100644
--- a/x-pack/test/functional/apps/painless_lab/painless_lab_flyout.ts
+++ b/x-pack/test/functional/apps/painless_lab/painless_lab_flyout.ts
@@ -5,12 +5,29 @@
  * 2.0.
  */
 
+import expect from '@kbn/expect';
 import { FtrProviderContext } from '../../ftr_provider_context';
 
+const TEST_SCRIPT = `return 1;`;
+const TEST_SCRIPT_REQUEST = `POST _scripts/painless/_execute
+{
+  "script": {
+    "source": """${TEST_SCRIPT}""",
+    "params": {
+      "string_parameter": "string value",
+      "number_parameter": 1.5,
+      "boolean_parameter": true
+    }
+  }
+}`;
+const TEST_SCRIPT_RESPONSE = `"1"`;
+
 export default function ({ getService, getPageObjects }: FtrProviderContext) {
   const retry = getService('retry');
   const PageObjects = getPageObjects(['common', 'console', 'header']);
   const testSubjects = getService('testSubjects');
+  const find = getService('find');
+  const monacoEditor = getService('monacoEditor');
 
   describe('Painless lab', function describeIndexTests() {
     before(async () => {
@@ -18,12 +35,27 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
       await retry.waitFor('Wait for editor to be visible', async () => {
         return testSubjects.isDisplayed('painless_lab');
       });
+      // replace the default script with a simpler one
+      await monacoEditor.setCodeEditorValue(TEST_SCRIPT);
     });
 
     it('click show API request button and flyout should appear in page', async () => {
       await testSubjects.click('btnViewRequest');
-
       await testSubjects.existOrFail('painlessLabRequestFlyoutHeader', { timeout: 10 * 1000 });
     });
+
+    it('validate request body is the expected', async () => {
+      const requestText = await testSubjects.getVisibleText('painlessLabFlyoutRequest');
+      expect(requestText).equal(TEST_SCRIPT_REQUEST);
+    });
+
+    it('validate response body is the expected', async () => {
+      await find.clickByCssSelector('#response');
+      await retry.waitFor('Wait for response to change', async () => {
+        return (
+          (await testSubjects.getVisibleText('painlessLabFlyoutResponse')) === TEST_SCRIPT_RESPONSE
+        );
+      });
+    });
   });
 }