Float64 Test

1import { describe, expect, it } from "vitest";
2import { query } from "./clickhouse.js";
3import { NeedMoreData, Cursor } from "../src/readers/core.js";
4import { readFloat64 } 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("readFloat64", () => {
11  it("decodes 0", async () => {
12    const r = await reader("toFloat64(0)");
13    expect(readFloat64(r)).toBe(0);
14    expect(r.pos).toBe(8);
15  });
16
17  it("decodes 1.5", async () => {
18    expect(readFloat64(await reader("toFloat64(1.5)"))).toBe(1.5);
19  });
20
21  // float64 represents 0.1 exactly as the same double JS uses.
22  it("decodes 0.1", async () => {
23    expect(readFloat64(await reader("toFloat64(0.1)"))).toBe(0.1);
24  });
25
26  it("decodes -inf", async () => {
27    expect(readFloat64(await reader("toFloat64(-inf)"))).toBe(-Infinity);
28  });
29
30  describe("advance() edge cases", () => {
31    it("throws NeedMoreData for every incomplete prefix (0 .. full.length-1)", async () => {
32      const full = await query("SELECT toFloat64(1.5) FORMAT RowBinary");
33      for (let len = 0; len < full.length; len++) {
34        const r = new Cursor(full.subarray(0, len));
35        let thrown: unknown;
36        try {
37          readFloat64(r);
38        } catch (e) {
39          thrown = e;
40        }
41        expect(thrown, `prefix length ${len} of ${full.length}`).toBe(
42          NeedMoreData,
43        );
44      }
45    });
46  });
47});