import { describe, it } from "node:test";
import assert from "node:assert/strict";
import { chunkText } from "./chunk.js";

describe("chunkText", () => {
    it("returns empty array for blank input", () => {
        assert.deepEqual(chunkText(""), []);
        assert.deepEqual(chunkText("   "), []);
    });

    it("keeps short text as a single chunk", () => {
        const text = "A short paragraph.";
        assert.deepEqual(chunkText(text), [text]);
    });

    it("splits long text into overlapping chunks under 2000 chars", () => {
        const word = "word ";
        const text = word.repeat(900);
        const chunks = chunkText(text);
        assert.ok(chunks.length > 1);
        for (const chunk of chunks) {
            assert.ok(chunk.length <= 2000);
        }
        const overlap = chunks[0].slice(-50);
        assert.ok(chunks[1].includes(overlap.trim().slice(0, 20)));
    });
});