const messages = makeMessages(4, 4000);

const parts = splitMessagesByTokenShare(messages, 2);

expect(parts.length).toBeGreaterThanOrEqual(2);

expect(parts[0]?.length).toBeGreaterThan(0);

expect(parts[1]?.length).toBeGreaterThan(0);

expect(parts.flat().length).toBe(messages.length);

expect(parts.map((chunk) => chunk.map((msg) => msg.timestamp))).toEqual([

[1, 2],

[3, 4],

]);

});

it("preserves message order across parts", () => {

const resultTimestamps = chunkWithAssistant

.filter((m) => m.role === "toolResult")

.map((m) => m.timestamp);

expect(resultTimestamps).toContain(3);

expect(resultTimestamps).toContain(4);

expect(resultTimestamps).toEqual([3, 4]);

expect(parts.flat().length).toBe(messages.length);

});

const parts = splitMessagesByTokenShare(messages, 2);

expect(parts.length).toBe(2);

const chunk1Roles = parts[0].map((m) => m.role);

expect(chunk1Roles).toContain("assistant");

expect(chunk1Roles).toContain("toolResult");

expect(parts.flat().length).toBe(messages.length);

expect(parts.map((chunk) => chunk.map((msg) => msg.timestamp))).toEqual([[1, 2], [3]]);

});

it("splits before a trailing completed tool-call pair", () => {

const parts = splitMessagesByTokenShare(messages, 2);

expect(parts.length).toBe(2);

expect(parts.flat().length).toBe(messages.length);

expect(parts.map((chunk) => chunk.map((msg) => msg.timestamp))).toEqual([[1], [2, 3]]);

});

it("splits before unfinished tool-call turns that never get a result", () => {