fix(Remove Duplicates Node): Tolerate null fields (#9642)

packages/nodes-base/nodes/Transform/RemoveDuplicates/test/RemoveDuplicates.test.ts

@@ -1,5 +1,62 @@
+import type { INode } from 'n8n-workflow';
+import { validateInputData } from '../utils';
 import { testWorkflows, getWorkflowFilenames } from '@test/nodes/Helpers';
 
 const workflows = getWorkflowFilenames(__dirname);
 
 describe('Test Remove Duplicates Node', () => testWorkflows(workflows));
+
+describe('Test Remove Duplicates Node, validateInputData util', () => {
+	test('Should throw error for version 1', () => {
+		expect(() =>
+			validateInputData(
+				{
+					name: 'Remove Duplicates',
+					type: 'n8n-nodes-base.removeDuplicates',
+					typeVersion: 1,
+				} as INode,
+				[
+					{ json: { country: 'uk' } },
+					{ json: { country: 'us' } },
+					{ json: { country: 'uk' } },
+					{ json: { country: null } },
+				],
+				['country'],
+				false,
+			),
+		).toThrow("'country' isn't always the same type");
+	});
+	test('Should ignore null values and not throw error for version grater than 1', () => {
+		expect(() =>
+			validateInputData(
+				{
+					name: 'Remove Duplicates',
+					type: 'n8n-nodes-base.removeDuplicates',
+					typeVersion: 1.1,
+				} as INode,
+				[
+					{ json: { country: 'uk' } },
+					{ json: { country: 'us' } },
+					{ json: { country: 'uk' } },
+					{ json: { country: null } },
+				],
+				['country'],
+				false,
+			),
+		).not.toThrow();
+	});
+	test('Should throw error for different types, version grater than 1', () => {
+		expect(() =>
+			validateInputData(
+				{
+					name: 'Remove Duplicates',
+					type: 'n8n-nodes-base.removeDuplicates',
+					typeVersion: 1.1,
+				} as INode,
+				[{ json: { id: 1 } }, { json: { id: '1' } }, { json: { id: 2 } }, { json: { id: null } }],
+				['id'],
+				false,
+			),
+		).toThrow("'id' isn't always the same type");
+	});
+});