Function captureRequestBody

packages/kosong/test/google-genai.test.ts:48–81

Capture the request body by mocking the client's generateContentStream.

(
  provider: GoogleGenAIChatProvider,
  systemPrompt: string,
  tools: Tool[],
  history: Message[],
)

/** Capture the request body by mocking the client's generateContentStream. */
async function captureRequestBody(
  provider: GoogleGenAIChatProvider,
  systemPrompt: string,
  tools: Tool[],
  history: Message[],
): Promise<Record<string, unknown>> {
  let capturedBody: Record<string, unknown> | undefined;

  const mockModels = (provider as any)._client.models as Record<string, unknown>;

  async function* mockStream() {
    yield makeGenerateContentResponse();
  }

  mockModels['generateContentStream'] = vi.fn().mockImplementation((params: unknown) => {
    capturedBody = params as Record<string, unknown>;
    return Promise.resolve(mockStream());
  });

  mockModels['generateContent'] = vi.fn().mockImplementation((params: unknown) => {
    capturedBody = params as Record<string, unknown>;
    return Promise.resolve(makeGenerateContentResponse());
  });

  const stream = await provider.generate(systemPrompt, tools, history);
  for await (const part of stream) {
    void part;
  }

  if (capturedBody === undefined) {
    throw new Error('Expected provider.generate() to call a Google GenAI model endpoint');
  }
  return capturedBody;
}

/** Collect all parts from a StreamedMessage. */
async function collectParts(msg: {