88 lines
2.3 KiB
TypeScript
88 lines
2.3 KiB
TypeScript
import assert from 'node:assert/strict';
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import test, { describe } from 'node:test';
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import { PduFramer } from '../src/pdu-framer.ts';
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import { objToPdu } from '../src/pdu.ts';
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function pdu(seqNr: number): Buffer {
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const { buffer } = objToPdu({ cmdName: 'enquire_link', seqNr });
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assert.ok(buffer);
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return buffer;
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}
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describe('PduFramer', () => {
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test('yields nothing until a whole PDU has arrived', () => {
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const framer = new PduFramer();
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const whole = pdu(1);
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framer.push(whole.subarray(0, 8));
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assert.deepEqual(framer.next(), { pdus: [] });
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framer.push(whole.subarray(8));
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assert.deepEqual(framer.next(), { pdus: [whole] });
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});
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test('splits several PDUs delivered in one chunk', () => {
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const framer = new PduFramer();
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framer.push(Buffer.concat([pdu(1), pdu(2), pdu(3)]));
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const { pdus } = framer.next();
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assert.ok(pdus);
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assert.equal(pdus.length, 3);
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assert.deepEqual(pdus[2], pdu(3));
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});
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test('reassembles a PDU dribbled one octet at a time', () => {
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const framer = new PduFramer();
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const whole = pdu(42);
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for (const octet of whole) {
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framer.push(Buffer.from([octet]));
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}
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assert.deepEqual(framer.next(), { pdus: [whole] });
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assert.equal(framer.buffered, 0);
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});
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test('keeps a trailing partial PDU buffered for the next chunk', () => {
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const framer = new PduFramer();
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const second = pdu(2);
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framer.push(Buffer.concat([pdu(1), second.subarray(0, 4)]));
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const first = framer.next();
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assert.ok(first.pdus);
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assert.equal(first.pdus.length, 1);
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assert.equal(framer.buffered, 4);
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framer.push(second.subarray(4));
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assert.deepEqual(framer.next(), { pdus: [second] });
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});
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// 0.4.0 read a command length of 0 as "discard the buffer" and looped; anything absurd was
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// simply trusted and allocated.
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test('reports an impossible command length instead of trusting it', () => {
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const zero = new PduFramer();
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const huge = new PduFramer();
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zero.push(Buffer.alloc(16));
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assert.ok(zero.next().err instanceof Error);
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huge.push(Buffer.from('ffffffff0000001500000000000000ff', 'hex'));
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assert.ok(huge.next().err instanceof Error);
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});
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test('ignores empty chunks', () => {
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const framer = new PduFramer();
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framer.push(Buffer.alloc(0));
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assert.equal(framer.buffered, 0);
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assert.deepEqual(framer.next(), { pdus: [] });
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});
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});
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