Int16 Test

1import { describe, expect, it } from "vitest";
2import { query } from "./clickhouse.js";
3import { NeedMoreData, Cursor } from "../src/readers/core.js";
4import { readInt16 } from "../src/readers/integers.js";
5
6/**
7 * Int16 is 2 bytes, little-endian, two's-complement. Each case selects the
8 * value with `FORMAT RowBinary` and decodes the bytes the server produces.
9 */
10async function int16Reader(expr: string): Promise<Cursor> {
11  return new Cursor(await query(`SELECT toInt16(${expr}) FORMAT RowBinary`));
12}
13
14describe("readInt16", () => {
15  it("decodes 0", async () => {
16    const r = await int16Reader("0");
17    expect(readInt16(r)).toBe(0);
18    expect(r.pos).toBe(2);
19  });
20
21  it("decodes 1", async () => {
22    const r = await int16Reader("1");
23    expect(readInt16(r)).toBe(1);
24  });
25
26  it("decodes -1 (0xffff)", async () => {
27    const r = await int16Reader("-1");
28    expect(readInt16(r)).toBe(-1);
29  });
30
31  // Confirms little-endian byte order: 258 = 0x0102 -> bytes 02 01.
32  it("decodes 258 (little-endian byte order)", async () => {
33    const r = await int16Reader("258");
34    expect(readInt16(r)).toBe(258);
35  });
36
37  it("decodes 32767 (max)", async () => {
38    const r = await int16Reader("32767");
39    expect(readInt16(r)).toBe(32767);
40  });
41
42  it("decodes -32768 (min)", async () => {
43    const r = await int16Reader("-32768");
44    expect(readInt16(r)).toBe(-32768);
45  });
46
47  // Guards the byteOffset handling: a Buffer that is a window into a larger
48  // ArrayBuffer (nonzero byteOffset) must still decode correctly.
49  it("decodes from a buffer window with a nonzero byteOffset", () => {
50    const ab = Uint8Array.from([0xaa, 0xbb, 0xcc, 0x02, 0x01]).buffer; // 258 at offset 3
51    const sub = Buffer.from(ab, 3, 2);
52    expect(sub.byteOffset).toBe(3);
53    expect(readInt16(new Cursor(sub))).toBe(258);
54  });
55
56  describe("advance() edge cases", () => {
57    it("throws NeedMoreData for every incomplete prefix (0 .. full.length-1)", async () => {
58      const full = await query("SELECT toInt16(-12345) FORMAT RowBinary");
59      for (let len = 0; len < full.length; len++) {
60        const r = new Cursor(full.subarray(0, len));
61        let thrown: unknown;
62        try {
63          readInt16(r);
64        } catch (e) {
65          thrown = e;
66        }
67        expect(thrown, `prefix length ${len} of ${full.length}`).toBe(
68          NeedMoreData,
69        );
70      }
71    });
72  });
73});