Tuple Named Test

1import { describe, expect, it } from "vitest";
2import { query } from "./clickhouse.js";
3import { readNullable, readTupleNamed } from "../src/readers/composite.js";
4import { NeedMoreData, Cursor } from "../src/readers/core.js";
5import { readUInt32, readUInt8 } from "../src/readers/integers.js";
6import { readString } from "../src/readers/strings.js";
7
8async function reader(expr: string): Promise<Cursor> {
9  return new Cursor(await query(`SELECT ${expr} FORMAT RowBinary`));
10}
11
12describe("readTupleNamed", () => {
13  it("decodes a named tuple into an object (same wire as unnamed)", async () => {
14    const r = await reader("CAST((42, 'hi') AS Tuple(a UInt32, b String))");
15    const obj = readTupleNamed({
16      a: readUInt32,
17      b: readString,
18    })(r);
19    expect(obj).toEqual({ a: 42, b: "hi" });
20    expect(r.pos).toBe(7); // 4 (UInt32) + 1 (len) + 2 ("hi")
21  });
22
23  // Keys are read in listed order; the result object carries the names.
24  it("composes with Nullable and preserves field names", async () => {
25    const r = await reader(
26      "CAST((1, NULL) AS Tuple(id UInt8, parent Nullable(UInt8)))",
27    );
28    const obj = readTupleNamed({
29      id: readUInt8,
30      parent: readNullable(readUInt8),
31    })(r);
32    expect(obj).toEqual({ id: 1, parent: null });
33    expect(r.pos).toBe(2);
34  });
35
36  describe("advance() edge cases", () => {
37    it("throws NeedMoreData for every incomplete prefix (0 .. full.length-1)", async () => {
38      const full = await query(
39        "SELECT CAST((1, 'x') AS Tuple(a UInt8, b String)) FORMAT RowBinary",
40      );
41      for (let len = 0; len < full.length; len++) {
42        const r = new Cursor(full.subarray(0, len));
43        let thrown: unknown;
44        try {
45          readTupleNamed({ a: readUInt8, b: readString })(r);
46        } catch (e) {
47          thrown = e;
48        }
49        expect(thrown, `prefix length ${len} of ${full.length}`).toBe(
50          NeedMoreData,
51        );
52      }
53    });
54  });
55});