diff --git a/test/convert/transformers/decomposedLabelsTransformer.test.ts b/test/convert/transformers/decomposedLabelsTransformer.test.ts
index 924eab931..22b42b68c 100644
--- a/test/convert/transformers/decomposedLabelsTransformer.test.ts
+++ b/test/convert/transformers/decomposedLabelsTransformer.test.ts
@@ -5,7 +5,10 @@
  * For full license text, see LICENSE.txt file in the repo root or https://opensource.org/licenses/BSD-3-Clause
  */
 import { join } from 'node:path';
-import { expect } from 'chai';
+import { expect, assert } from 'chai';
+import { parser } from '../../../src/utils/metadata';
+import { stream2buffer } from '../../../src/convert/streams';
+import { DecomposedLabelsFinalizer } from '../../../src/convert/convertContext/decomposedLabelsFinalizer';
 import { ComponentSet } from '../../../src/collections/componentSet';
 import { RegistryAccess } from '../../../src/registry/registryAccess';
 import {
@@ -14,6 +17,7 @@ import {
   ONLY_LABEL_CMP_IN_ANOTHER_DIR_CMP,
   ONLY_LABEL_CMP_IN_DEFAULT_DIR_CMP,
   ONLY_LABEL_NO_DIR_CMP,
+  OTHER_LABEL_CMP,
   THREE_CUSTOM_LABELS_CMP,
 } from '../../mock/type-constants/decomposedCustomLabelsConstant';
 import {
@@ -129,5 +133,43 @@ describe('DecomposedCustomLabelTransformer', () => {
         expect(stateEntry?.fullName).to.deep.equal(component.fullName);
       });
     });
+    describe('finalizer', () => {
+      it('single label from source to mdapi', async () => {
+        const component = ONLY_LABEL_CMP_IN_DEFAULT_DIR_CMP;
+        const xf = new LabelMetadataTransformer(regAcc);
+        await xf.toMetadataFormat(component);
+        const finalizer = new DecomposedLabelsFinalizer();
+        finalizer.customLabelsType = regAcc.getTypeByName('CustomLabels');
+        finalizer.transactionState = xf.context.decomposedLabels.transactionState;
+        const result = await finalizer.finalize();
+        expect(result).to.have.length(1);
+        expect(result[0].component.fullName).to.equal('CustomLabels');
+        expect(result[0].component.type.name).to.equal('CustomLabels');
+        expect(result[0].writeInfos).to.have.length(1);
+        assert(result[0].writeInfos[0].source);
+        const contents = (await stream2buffer(result[0].writeInfos[0].source)).toString();
+        expect(parser.parse(contents)).to.deep.equal(await ONE_CUSTOM_LABELS_CMP.parseXml());
+      });
+      it('2 labels from source to mdapi', async () => {
+        const component1 = ONLY_LABEL_CMP_IN_DEFAULT_DIR_CMP;
+        const component2 = OTHER_LABEL_CMP;
+        const xf = new LabelMetadataTransformer(regAcc);
+        await xf.toMetadataFormat(component1);
+        await xf.toMetadataFormat(component2);
+        const finalizer = new DecomposedLabelsFinalizer();
+        finalizer.customLabelsType = regAcc.getTypeByName('CustomLabels');
+        finalizer.transactionState = xf.context.decomposedLabels.transactionState;
+        const result = await finalizer.finalize();
+        expect(result).to.have.length(1);
+        expect(result[0].component.fullName).to.equal('CustomLabels');
+        expect(result[0].component.type.name).to.equal('CustomLabels');
+        // still produces only 1 writeInfo
+        expect(result[0].writeInfos).to.have.length(1);
+        assert(result[0].writeInfos[0].source);
+        const contents = (await stream2buffer(result[0].writeInfos[0].source)).toString();
+        // with 2 labels in it
+        expect(parser.parse(contents).CustomLabels.labels).to.have.length(2);
+      });
+    });
   });
 });
diff --git a/test/mock/type-constants/decomposedCustomLabelsConstant.ts b/test/mock/type-constants/decomposedCustomLabelsConstant.ts
index 2c475cf5d..cf891da92 100644
--- a/test/mock/type-constants/decomposedCustomLabelsConstant.ts
+++ b/test/mock/type-constants/decomposedCustomLabelsConstant.ts
@@ -171,3 +171,29 @@ export const ONLY_LABEL_NO_DIR_CMP = new SourceComponent(
     },
   ])
 );
+
+export const OTHER_LABEL_CMP = new SourceComponent(
+  {
+    name: 'OtherLabel',
+    type: customLabelType,
+    xml: join('labels', 'OtherLabel.label-meta.xml'),
+  },
+  new VirtualTreeContainer([
+    {
+      dirPath: 'labels',
+      children: [
+        {
+          name: 'OtherLabel.label-meta.xml',
+          data: Buffer.from(`<?xml version="1.0" encoding="UTF-8"?>
+<CustomLabel xmlns="http://soap.sforce.com/2006/04/metadata">
+  <fullName>OtherLabel</fullName>
+  <language>en_US</language>
+  <protected>true</protected>
+  <shortDescription>OtherLabel</shortDescription>
+  <value>OtherLabel</value>
+</CustomLabel>`),
+        },
+      ],
+    },
+  ])
+);