BFloat16 Test

1import { describe, expect, it } from "vitest";
2import { query } from "./clickhouse.js";
3import { NeedMoreData, Cursor } from "../src/readers/core.js";
4import { readBFloat16 } from "../src/readers/floats.js";
5
6async function reader(expr: string): Promise<Cursor> {
7  return new Cursor(await query(`SELECT ${expr} FORMAT RowBinary`));
8}
9
10describe("readBFloat16", () => {
11  it("decodes 0", async () => {
12    const r = await reader("toBFloat16(0)");
13    expect(readBFloat16(r)).toBe(0);
14    expect(r.pos).toBe(2);
15  });
16
17  // Values whose float32 mantissa fits in BFloat16's 7 bits, so they survive
18  // the round-trip exactly.
19  it("decodes 1.5", async () => {
20    expect(readBFloat16(await reader("toBFloat16(1.5)"))).toBe(1.5);
21  });
22
23  it("decodes -2.5", async () => {
24    expect(readBFloat16(await reader("toBFloat16(-2.5)"))).toBe(-2.5);
25  });
26
27  describe("advance() edge cases", () => {
28    it("throws NeedMoreData for every incomplete prefix (0 .. full.length-1)", async () => {
29      const full = await query("SELECT toBFloat16(1.5) FORMAT RowBinary");
30      for (let len = 0; len < full.length; len++) {
31        const r = new Cursor(full.subarray(0, len));
32        let thrown: unknown;
33        try {
34          readBFloat16(r);
35        } catch (e) {
36          thrown = e;
37        }
38        expect(thrown, `prefix length ${len} of ${full.length}`).toBe(
39          NeedMoreData,
40        );
41      }
42    });
43  });
44});