Function streamWithFinish

packages/kosong/test/step.test.ts:456–479

(
      parts: StreamedMessagePart[],
      finishReason:
        | 'completed'
        | 'truncated'
        | 'tool_calls'
        | 'filtered'
        | 'paused'
        | 'other'
        | null,
      rawFinishReason: string | null,
    )

  describe('finishReason propagation', () => {
    function streamWithFinish(
      parts: StreamedMessagePart[],
      finishReason:
        | 'completed'
        | 'truncated'
        | 'tool_calls'
        | 'filtered'
        | 'paused'
        | 'other'
        | null,
      rawFinishReason: string | null,
    ): StreamedMessage {
      return {
        id: 'mock',
        usage: null,
        finishReason,
        rawFinishReason,
        async *[Symbol.asyncIterator](): AsyncIterator<StreamedMessagePart> {
          for (const part of parts) {
            yield part;
          }
        },
      };
    }

    it('copies stream.finishReason onto the StepResult', async () => {
      const stream = streamWithFinish([{ type: 'text', text: 'hi' }], 'truncated', 'length');