adds function tests

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

@@ -1,5 +1,57 @@
 import { testWorkflows, getWorkflowFilenames } from '@test/nodes/Helpers';
+import { NodeOperationError, type IExecuteFunctions, type IDataObject } from 'n8n-workflow';
+import { checkIfFieldExists, type Aggregations } from '../utils';
 
 const workflows = getWorkflowFilenames(__dirname);
 
 describe('Test Summarize Node', () => testWorkflows(workflows));
+
+describe('Test Summarize Node, checkIfFieldExists', () => {
+	let mockExecuteFunctions: IExecuteFunctions;
+
+	beforeEach(() => {
+		mockExecuteFunctions = {
+			getNode: jest.fn().mockReturnValue({ name: 'test-node' }),
+		} as unknown as IExecuteFunctions;
+	});
+
+	const items = [{ a: 1 }, { b: 2 }, { c: 3 }];
+
+	it('should not throw error if all fields exist', () => {
+		const aggregations: Aggregations = [
+			{ aggregation: 'sum', field: 'a' },
+			{ aggregation: 'count', field: 'c' },
+		];
+		const getValue = (item: IDataObject, field: string) => item[field];
+		expect(() => {
+			checkIfFieldExists.call(mockExecuteFunctions, items, aggregations, getValue);
+		}).not.toThrow();
+	});
+
+	it('should throw NodeOperationError if any field does not exist', () => {
+		const aggregations: Aggregations = [
+			{ aggregation: 'sum', field: 'b' },
+			{ aggregation: 'count', field: 'd' },
+		];
+		const getValue = (item: IDataObject, field: string) => item[field];
+		expect(() => {
+			checkIfFieldExists.call(mockExecuteFunctions, items, aggregations, getValue);
+		}).toThrow(NodeOperationError);
+	});
+
+	it("should throw NodeOperationError with error message containing the field name that doesn't exist", () => {
+		const aggregations: Aggregations = [{ aggregation: 'count', field: 'D' }];
+		const getValue = (item: IDataObject, field: string) => item[field];
+		expect(() => {
+			checkIfFieldExists.call(mockExecuteFunctions, items, aggregations, getValue);
+		}).toThrow("The field 'D' does not exist in any items");
+	});
+
+	it('should not throw error if field is empty string', () => {
+		const aggregations: Aggregations = [{ aggregation: 'count', field: '' }];
+		const getValue = (item: IDataObject, field: string) => item[field];
+		expect(() => {
+			checkIfFieldExists.call(mockExecuteFunctions, items, aggregations, getValue);
+		}).not.toThrow();
+	});
+});