File size: 2,576 Bytes
5cb63c1 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 | import { describe, expect, it } from "vitest";
import { truncateCloseReason } from "./close-reason.js";
describe("truncateCloseReason", () => {
it("returns the reason unchanged when it fits within the byte cap", () => {
expect(truncateCloseReason("short reason")).toBe("short reason");
});
it("returns 'invalid handshake' for empty string", () => {
expect(truncateCloseReason("")).toBe("invalid handshake");
});
it("truncates ASCII-only reasons at exactly maxBytes", () => {
const reason = "a".repeat(200);
const result = truncateCloseReason(reason);
expect(Buffer.byteLength(result)).toBe(120);
expect(result).toBe("a".repeat(120));
});
it("does not cut mid-UTF-8 sequence — result stays within maxBytes", () => {
// 118 ASCII chars + emoji starting at byte 118; emoji is 4 bytes so the
// naive subarray(0, 120) would cut it at byte 2, leaving two continuation
// bytes that decode to two U+FFFD (3 bytes each) = 122 bytes total.
const reason = "x".repeat(118) + "😀".repeat(5);
const result = truncateCloseReason(reason);
expect(Buffer.byteLength(result)).toBeLessThanOrEqual(120);
expect(result).not.toContain("�");
expect(result).toBe("x".repeat(118));
});
it("does not cut mid-UTF-8 sequence for 2-byte chars (e.g. é)", () => {
// Each 'é' is 2 bytes. 119 'a' + 'é' = 121 bytes; cap is 120, which falls
// at the second byte of 'é'. The fix should back up and return 119 'a'.
const reason = "a".repeat(119) + "é".repeat(5);
const result = truncateCloseReason(reason);
expect(Buffer.byteLength(result)).toBeLessThanOrEqual(120);
expect(result).not.toContain("�");
expect(result).toBe("a".repeat(119));
});
it("does not cut mid-UTF-8 sequence for 3-byte chars (e.g. ✓)", () => {
// Each '✓' is 3 bytes. 119 'a' + '✓' = 122 bytes; the naive slice at 120
// cuts the second byte of '✓'. The fix backs up to byte 119.
const reason = "a".repeat(119) + "✓".repeat(5);
const result = truncateCloseReason(reason);
expect(Buffer.byteLength(result)).toBeLessThanOrEqual(120);
expect(result).not.toContain("�");
expect(result).toBe("a".repeat(119));
});
it("respects a custom maxBytes cap", () => {
const reason = "😀".repeat(10); // each 4 bytes = 40 bytes
const result = truncateCloseReason(reason, 10);
expect(Buffer.byteLength(result)).toBeLessThanOrEqual(10);
expect(result).not.toContain("�");
expect(result).toBe("😀".repeat(2)); // 8 bytes, next emoji would exceed 10
});
});
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