fix(Text Classifier Node): Return error for empty inputText (#15390)

packages/@n8n/nodes-langchain/nodes/chains/TextClassifier/test/processItem.test.ts

@@ -0,0 +1,144 @@
+import { ChatPromptTemplate } from '@langchain/core/prompts';
+import { FakeChatModel } from '@langchain/core/utils/testing';
+import { mock } from 'jest-mock-extended';
+import type { IExecuteFunctions } from 'n8n-workflow';
+import { NodeOperationError } from 'n8n-workflow';
+
+import * as tracing from '@utils/tracing';
+
+import { processItem } from '../processItem';
+
+jest.mock('@utils/tracing', () => ({
+	getTracingConfig: jest.fn(() => ({})),
+}));
+
+jest.mock('@langchain/core/prompts', () => ({
+	ChatPromptTemplate: {
+		fromMessages: jest.fn(),
+	},
+	SystemMessagePromptTemplate: {
+		fromTemplate: jest.fn().mockReturnValue({
+			format: jest.fn(),
+		}),
+	},
+}));
+
+describe('processItem', () => {
+	let mockContext: jest.Mocked<IExecuteFunctions>;
+	let fakeLLM: FakeChatModel;
+
+	beforeEach(() => {
+		mockContext = mock<IExecuteFunctions>();
+		fakeLLM = new FakeChatModel({});
+
+		mockContext.getNodeParameter.mockImplementation((param, _itemIndex, defaultValue) => {
+			if (param === 'inputText') return 'Test input';
+			if (param === 'options.systemPromptTemplate') return 'Test system prompt';
+			return defaultValue;
+		});
+
+		jest.clearAllMocks();
+	});
+
+	it('should throw error for empty input text', async () => {
+		mockContext.getNodeParameter.mockImplementation((param, _itemIndex, defaultValue) => {
+			if (param === 'inputText') return '';
+			return defaultValue;
+		});
+
+		await expect(
+			processItem(
+				mockContext,
+				0,
+				{ json: {} },
+				fakeLLM,
+				{ getFormatInstructions: () => 'format instructions' } as any,
+				[{ category: 'test', description: 'test category' }],
+				'multi class prompt',
+				undefined,
+			),
+		).rejects.toThrow(NodeOperationError);
+	});
+
+	it('should process item with correct parameters', async () => {
+		const mockParser = {
+			getFormatInstructions: () => '[format instructions]',
+		};
+
+		const mockChain = {
+			invoke: jest.fn().mockResolvedValue({ test: true }),
+		};
+
+		const mockPipe = jest.fn().mockReturnValue({
+			pipe: jest.fn().mockReturnValue({
+				withConfig: jest.fn().mockReturnValue(mockChain),
+			}),
+		});
+
+		const mockPrompt = {
+			pipe: mockPipe,
+		};
+
+		jest.mocked(ChatPromptTemplate.fromMessages).mockReturnValue(mockPrompt as any);
+
+		const result = await processItem(
+			mockContext,
+			0,
+			{ json: {} },
+			fakeLLM,
+			mockParser as any,
+			[{ category: 'test', description: 'test category' }],
+			'multi class prompt',
+			undefined,
+		);
+
+		expect(result).toEqual({ test: true });
+		expect(mockContext.getNodeParameter).toHaveBeenCalledWith('inputText', 0);
+		expect(mockContext.getNodeParameter).toHaveBeenCalledWith(
+			'options.systemPromptTemplate',
+			0,
+			expect.any(String),
+		);
+		expect(tracing.getTracingConfig).toHaveBeenCalledWith(mockContext);
+	});
+
+	it('should handle fallback prompt', async () => {
+		const mockParser = {
+			getFormatInstructions: () => '[format instructions]',
+		};
+
+		const mockChain = {
+			invoke: jest.fn().mockResolvedValue({ category: 'test' }),
+		};
+
+		const mockPipe = jest.fn().mockReturnValue({
+			pipe: jest.fn().mockReturnValue({
+				withConfig: jest.fn().mockReturnValue(mockChain),
+			}),
+		});
+
+		const mockPrompt = {
+			pipe: mockPipe,
+		};
+
+		jest.mocked(ChatPromptTemplate.fromMessages).mockReturnValue(mockPrompt as any);
+
+		await processItem(
+			mockContext,
+			0,
+			{ json: {} },
+			fakeLLM,
+			mockParser as any,
+			[{ category: 'test', description: 'test category' }],
+			'multi class prompt',
+			'fallback prompt',
+		);
+
+		expect(mockContext.getNodeParameter).toHaveBeenCalledWith(
+			'options.systemPromptTemplate',
+			0,
+			expect.any(String),
+		);
+		expect(tracing.getTracingConfig).toHaveBeenCalledWith(mockContext);
+	});
+});