Tests for chat completion

src/functions/functions.js

@@ -1,6 +1,7 @@
 const COMPLETION_ENTITY_KIND = 'openai-excel-formulas:chat-completion';
 
-CustomFunctions.associate('CHAT_COMPLETE', async (messages, params) => {
+CustomFunctions.associate('CHAT_COMPLETE', chatComplete);
+async function chatComplete(messages, params) {
   const {
     API_KEY: apiKey,
     API_BASE: apiBase = 'https://api.openai.com/',
@@ -26,7 +27,9 @@ CustomFunctions.associate('CHAT_COMPLETE', async (messages, params) => {
   try {
     const requestBody = {
       ...userParams,
-      messages: messages.map(([role, content]) => ({ role, content })),
+      messages: messages
+        .filter(([role]) => role !== 0)
+        .map(([role, content]) => ({ role, content })),
     };
 
     const response = await fetch(`${apiBase}v1/chat/completions`, {
@@ -78,7 +81,7 @@ CustomFunctions.associate('CHAT_COMPLETE', async (messages, params) => {
       e.message,
     );
   }
-});
+}
 
 // Terminology note: our _cost_ is driven by usage and OpenAI's _prices_.
 CustomFunctions.associate('COST', cost);
@@ -185,6 +188,7 @@ function mapObject(object, callback) {
 // For unit testing.
 if (typeof module === 'object') {
   module.exports = {
+    chatComplete,
     cost,
     cotAnswer,
   };

src/functions/functions.test.mjs

@@ -1,7 +1,178 @@
 import assert from 'node:assert';
-import { describe, it, mock } from 'node:test';
+import { describe, it } from 'node:test';
 import { makeCompletionEntity } from '../../testFramework/completionEntityStub.mjs';
-import { cost, cotAnswer } from './functions.js';
+import { chatComplete, cost, cotAnswer } from './functions.js';
+import { makeCompletionResponse } from '../../testFramework/completionResponseStub.mjs';
+
+describe('CHAT_COMPLETE', () => {
+  it('makes a completion for given messages', async (t) => {
+    const mockResponseBody = makeCompletionResponse({ content: 'Hello' });
+    t.mock.method(global, 'fetch', () => mockResponseOk(mockResponseBody));
+
+    const completion = await chatComplete(
+      [['user', 'Say hello']],
+      [['API_KEY', 'someapikey']],
+    );
+
+    const requestBody = JSON.parse(fetch.mock.calls[0].arguments[1].body);
+    assert.deepStrictEqual(requestBody.messages, [
+      { role: 'user', content: 'Say hello' },
+    ]);
+
+    assert.strictEqual(completion.text, 'Hello');
+  });
+
+  it('assembles messages structure for a single-cell prompt', async (t) => {
+    t.mock.method(global, 'fetch', () =>
+      mockResponseOk(makeCompletionResponse()),
+    );
+
+    await chatComplete([['Say hello']], [['API_KEY', 'someapikey']]);
+
+    const requestBody = JSON.parse(fetch.mock.calls[0].arguments[1].body);
+    assert.deepStrictEqual(requestBody.messages[1], {
+      role: 'user',
+      content: 'Say hello',
+    });
+  });
+
+  it('does not propagate empty cells in the messages range to the API', async (t) => {
+    t.mock.method(global, 'fetch', () =>
+      mockResponseOk(makeCompletionResponse()),
+    );
+
+    await chatComplete(
+      [
+        ['user', 'Say hello'],
+        [0, 0],
+      ],
+      [['API_KEY', 'someapikey']],
+    );
+
+    const requestBody = JSON.parse(fetch.mock.calls[0].arguments[1].body);
+    assert.strictEqual(requestBody.messages.length, 1);
+  });
+
+  it('propagates only the user parameters to the API', async (t) => {
+    t.mock.method(global, 'fetch', () =>
+      mockResponseOk(makeCompletionResponse()),
+    );
+
+    await chatComplete(
+      [['Say hello']],
+      [
+        ['API_KEY', 'someapikey'],
+        ['temperature', 0.3],
+      ],
+    );
+
+    const requestBody = JSON.parse(fetch.mock.calls[0].arguments[1].body);
+    assert.strictEqual(requestBody.temperature, 0.3);
+    assert(!('API_KEY' in requestBody));
+  });
+
+  it('does not propagate empty cells in the params range to the API', async (t) => {
+    const mockResponseBody = {
+      id: 'chatcmpl-8X6b8XW77Md4oc06Yd3tc18lFzqT9',
+      object: 'chat.completion',
+      created: 0,
+      model: 'gpt-3.5-turbo-0613',
+      choices: [
+        {
+          index: 0,
+          message: { role: 'assistant', content: 'Hello' },
+          logprobs: null,
+          finish_reason: 'stop',
+        },
+      ],
+      usage: { prompt_tokens: 78, completion_tokens: 23, total_tokens: 101 },
+      system_fingerprint: null,
+    };
+    t.mock.method(global, 'fetch', () => mockResponseOk(mockResponseBody));
+
+    await chatComplete(
+      [['user', 'Say hello']],
+      [
+        ['API_KEY', 'someapikey'],
+        [0, 0],
+      ],
+    );
+
+    const requestBody = JSON.parse(fetch.mock.calls[0].arguments[1].body);
+    assert(!('0' in requestBody));
+  });
+
+  it('throws an error when no API key is provided - key absent', () => {
+    assert.rejects(() => chatComplete([['Say hello']], []), {
+      code: '#VALUE!',
+      message: 'API_KEY is required',
+    });
+  });
+
+  it('throws an error when no API key is provided - value cell empty', () => {
+    assert.rejects(() => chatComplete([['Say hello']], [['API_KEY', 0]]), {
+      code: '#VALUE!',
+      message: 'API_KEY is required',
+    });
+  });
+
+  it('throws an error for an API error with a provided message', (t) => {
+    const errorResponseBody = {
+      error: {
+        message: "0 is less than the minimum of 1 - 'n'",
+        type: 'invalid_request_error',
+        param: null,
+        code: null,
+      },
+    };
+    t.mock.method(
+      global,
+      'fetch',
+      async () =>
+        new Response(JSON.stringify(errorResponseBody), {
+          status: 400,
+          headers: { 'Content-Type': 'application/json' },
+        }),
+    );
+
+    assert.rejects(
+      () => chatComplete([['Say hello']], [['API_KEY', 'someapikey']]),
+      {
+        code: '#N/A',
+        message: "API error: 0 is less than the minimum of 1 - 'n'",
+      },
+    );
+  });
+
+  it('throws an error for an API error not providing a message', (t) => {
+    const errorResponseBody = {
+      error: {
+        message: "0 is less than the minimum of 1 - 'n'",
+        type: 'invalid_request_error',
+        param: null,
+        code: null,
+      },
+    };
+    t.mock.method(
+      global,
+      'fetch',
+      async () =>
+        new Response('', {
+          status: 502,
+          statusText: 'Bad Gateway',
+          headers: { 'Content-Type': 'text/plain' },
+        }),
+    );
+
+    assert.rejects(
+      () => chatComplete([['Say hello']], [['API_KEY', 'someapikey']]),
+      {
+        code: '#N/A',
+        message: 'API error: 502 Bad Gateway',
+      },
+    );
+  });
+});
 
 describe('COST', () => {
   it('calculates the cost of a single completion', () => {
@@ -45,7 +216,7 @@ describe('COST', () => {
 });
 
 describe('COT_ANSWER', () => {
-  it('extracts the answer (basic case)', () => {
+  it('extracts the answer', () => {
     const completion = makeCompletionEntity({
       content:
         'The color of the door has been explicitly stated in the provided statement.\n\n<!-- END CoT -->\nBlue',
@@ -81,3 +252,10 @@ describe('COT_ANSWER', () => {
     assert.strictEqual(cotAnswer(completion, null), 'Blue');
   });
 });
+
+async function mockResponseOk(body) {
+  return new Response(JSON.stringify(body), {
+    status: 200,
+    headers: { 'Content-Type': 'application/json' },
+  });
+}

testFramework/completionEntityStub.mjs

@@ -3,7 +3,7 @@ export function makeCompletionEntity({
   modelUsed,
   tokensPrompt,
   tokensCompletion,
-}) {
+} = {}) {
   return {
     type: 'Entity',
     basicType: 'Error',

testFramework/completionResponseStub.mjs

@@ -0,0 +1,21 @@
+export function makeCompletionResponse({ content } = {}) {
+  return {
+    id: 'chatcmpl-00000000000000000000000000000',
+    object: 'chat.completion',
+    created: 0,
+    model: 'gpt-0-0000',
+    choices: [
+      {
+        index: 0,
+        message: {
+          role: 'assistant',
+          content: content ?? '',
+        },
+        logprobs: null,
+        finish_reason: 'stop',
+      },
+    ],
+    usage: { prompt_tokens: -1, completion_tokens: -1, total_tokens: -1 },
+    system_fingerprint: null,
+  };
+}

testFramework/excelStubs.cjs

@@ -1,5 +1,9 @@
 // Copy Excel constants from DevTools using "copy object".
 
+global.fetch = () => {
+  throw new Error('fetch() must be mocked');
+};
+
 global.CustomFunctions = {
   Error: class CustomFunctionsError {
     constructor(code, message) {
@@ -35,4 +39,15 @@ global.Excel = {
     notAvailable: 'NotAvailable',
     webImage: 'WebImage',
   },
+
+  RangeValueType: {
+    unknown: 'Unknown',
+    empty: 'Empty',
+    string: 'String',
+    integer: 'Integer',
+    double: 'Double',
+    boolean: 'Boolean',
+    error: 'Error',
+    richValue: 'RichValue',
+  },
 };