fix(Merge Node): Do not error if expected key is missing

packages/nodes-base/nodes/CompareDatasets/test/utils/utils.test.ts

@@ -0,0 +1,32 @@
+import type { INodeExecutionData } from 'n8n-workflow';
+import { checkInput } from '../../GenericFunctions';
+
+describe('Test Compare Datasets Node utils', () => {
+	it('test checkInput', () => {
+		const input1 = [
+			{ json: {} },
+			{
+				json: {
+					name: 'Test',
+					age: 30,
+				},
+			},
+			{
+				json: {
+					name: 'Test2',
+					age: 30,
+				},
+			},
+		];
+
+		expect(checkInput(input1).length).toEqual(2);
+
+		const input2: INodeExecutionData[] = [{ json: {} }];
+
+		expect(checkInput(input2).length).toEqual(0);
+
+		const input3 = undefined;
+
+		expect(checkInput(input3 as unknown as INodeExecutionData[]).length).toEqual(0);
+	});
+});