lobster/test/group_by.test.ts

import test from "node:test";
import assert from "node:assert/strict";

import { runPipeline } from "../src/runtime.js";
import { createDefaultRegistry } from "../src/commands/registry.js";
import { parsePipeline } from "../src/parser.js";

async function run(pipelineText: string, input: any[]) {
	const pipeline = parsePipeline(pipelineText);
	const registry = createDefaultRegistry();
	const res = await runPipeline({
		pipeline,
		registry,
		stdin: process.stdin,
		stdout: process.stdout,
		stderr: process.stderr,
		env: process.env,
		mode: "tool",
		input: (async function* () {
			for (const x of input) yield x;
		})(),
	});
	return res.items;
}

test("groupBy groups items by key and preserves group order", async () => {
	const input = [
		{ from: "a", id: 1 },
		{ from: "b", id: 2 },
		{ from: "a", id: 3 },
	];
	const out = await run("groupBy --key from", input);
	assert.equal(out.length, 2);
	assert.deepEqual(out[0].key, "a");
	assert.deepEqual(
		out[0].items.map((x: any) => x.id),
		[1, 3],
	);
	assert.equal(out[0].count, 2);
	assert.deepEqual(out[1].key, "b");
});

test("groupBy supports nested key paths", async () => {
	const input = [{ user: { id: "u1" } }, { user: { id: "u2" } }, { user: { id: "u1" } }];
	const out = await run("groupBy --key user.id", input);
	assert.deepEqual(
		out.map((g: any) => g.key),
		["u1", "u2"],
	);
	assert.equal(out[0].count, 2);
});