| 1 | // Run: tsx src/__tests__/markdown-worker-client.test.ts |
| 2 | // |
| 3 | // MarkdownWorkerClient protocol behavior: request ids, cancellation (stale |
| 4 | // responses dropped), in-process fallback when Worker is unavailable, dispose |
| 5 | // semantics, and pending-map hygiene across many cycles. Runs without a DOM: |
| 6 | // Node has no Worker global, which also exercises the fallback branch. |
| 7 | |
| 8 | import { |
| 9 | MarkdownWorkerClient, |
| 10 | type MarkdownParseResponse, |
| 11 | type MarkdownWorkerLike, |
| 12 | } from "../lib/markdownWorkerClient"; |
| 13 | import type { MarkdownBlock, MarkdownParseResult } from "../lib/markdownPipeline"; |
| 14 | import type { MarkdownWorkerRequest } from "../lib/markdownWorkerProtocol"; |
| 15 | |
| 16 | let passed = 0; |
| 17 | let failed = 0; |
| 18 | |
| 19 | function ok(value: unknown, label: string) { |
| 20 | if (value) { |
| 21 | process.stdout.write(` PASS ${label}\n`); |
| 22 | passed += 1; |
| 23 | } else { |
| 24 | process.stdout.write(` FAIL ${label}\n`); |
| 25 | failed += 1; |
| 26 | } |
| 27 | } |
| 28 | |
| 29 | function eq(actual: unknown, expected: unknown, label: string) { |
| 30 | if (actual === expected) ok(true, label); |
| 31 | else ok(false, `${label}: expected ${JSON.stringify(expected)}, got ${JSON.stringify(actual)}`); |
| 32 | } |
| 33 | |
| 34 | const tick = () => new Promise((resolve) => setTimeout(resolve, 0)); |
| 35 | |
| 36 | // Node has no Worker global: the client only attempts worker creation when one |
| 37 | // exists. Stub it so worker-path tests reach the injected fake; the fallback |
| 38 | // test below deletes it again. |
| 39 | (globalThis as { Worker?: unknown }).Worker = class {}; |
| 40 | |
| 41 | /** Manual-response fake worker: tests decide when (or whether) it answers. */ |
| 42 | class FakeWorker implements MarkdownWorkerLike { |
| 43 | onmessage: ((event: MessageEvent<MarkdownParseResponse>) => void) | null = null; |
| 44 | onerror: ((event: ErrorEvent) => void) | null = null; |
| 45 | sent: MarkdownWorkerRequest[] = []; |
| 46 | terminated = 0; |
| 47 | postMessage(request: MarkdownWorkerRequest): void { |
| 48 | this.sent.push(request); |
| 49 | } |
| 50 | respond(id: number, result: MarkdownParseResult): void { |
| 51 | this.onmessage?.({ data: { id, result } } as MessageEvent<MarkdownParseResponse>); |
| 52 | } |
| 53 | fail(id: number, error: string): void { |
| 54 | this.onmessage?.({ data: { id, error } } as MessageEvent<MarkdownParseResponse>); |
| 55 | } |
| 56 | crash(): void { |
| 57 | // Node 24 does not expose the browser ErrorEvent constructor. The client |
| 58 | // intentionally treats worker.onerror as a signal and does not inspect it. |
| 59 | this.onerror?.({ type: "error" } as ErrorEvent); |
| 60 | } |
| 61 | terminate(): void { |
| 62 | this.terminated += 1; |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | function sentAt(worker: FakeWorker, index: number): MarkdownWorkerRequest { |
| 67 | const request = worker.sent[index]; |
| 68 | if (!request) throw new Error(`missing worker request ${index}`); |
| 69 | return request; |
| 70 | } |
| 71 | |
| 72 | const BLOCKS: MarkdownBlock[] = [{ key: "b0", fingerprint: 1, children: [{ type: "text", value: "hi" }] }]; |
| 73 | const RESULT: MarkdownParseResult = { blocks: BLOCKS, selectionText: "hi", selectionRevision: 1 }; |
| 74 | |
| 75 | console.log("\nmarkdown worker client"); |
| 76 | |
| 77 | // ── happy path over a fake worker ──────────────────────────────────────────── |
| 78 | { |
| 79 | const worker = new FakeWorker(); |
| 80 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 81 | const handle = client.parse("hello"); |
| 82 | await tick(); |
| 83 | eq(worker.sent.length, 1, "request posted to the worker"); |
| 84 | worker.respond(worker.sent[0].id, RESULT); |
| 85 | const result = await handle.promise; |
| 86 | eq(result, RESULT, "response resolves with the full parse result"); |
| 87 | eq(client.pendingCount, 0, "pending map drains after a response"); |
| 88 | } |
| 89 | |
| 90 | // ── retained document protocol avoids full-source transfer and worker churn ─ |
| 91 | { |
| 92 | const worker = new FakeWorker(); |
| 93 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 94 | const open = client.parseDocument("doc-a", "hello", { priority: "interactive" }); |
| 95 | await tick(); |
| 96 | eq(sentAt(worker, 0).op, "open", "first document parse opens worker state"); |
| 97 | worker.respond(sentAt(worker, 0).id, RESULT); |
| 98 | await open.promise; |
| 99 | |
| 100 | const append = client.parseDocument("doc-a", "hello world", { priority: "interactive" }); |
| 101 | await tick(); |
| 102 | const appendRequest = sentAt(worker, 1); |
| 103 | eq(appendRequest.op, "append", "prefix growth uses append protocol"); |
| 104 | eq("text" in appendRequest ? appendRequest.text : undefined, " world", "append transfers only the new suffix"); |
| 105 | worker.respond(appendRequest.id, RESULT); |
| 106 | await append.promise; |
| 107 | |
| 108 | const replace = client.parseDocument("doc-a", "reset", { priority: "visible" }); |
| 109 | await tick(); |
| 110 | eq(sentAt(worker, 2).op, "replace", "non-prefix edits replace worker state"); |
| 111 | worker.respond(sentAt(worker, 2).id, RESULT); |
| 112 | await replace.promise; |
| 113 | |
| 114 | const finalize = client.parseDocument("doc-a", "reset!", { final: true }); |
| 115 | await tick(); |
| 116 | eq(sentAt(worker, 3).op, "finalize", "settled content finalizes with an authoritative snapshot"); |
| 117 | worker.respond(sentAt(worker, 3).id, RESULT); |
| 118 | await finalize.promise; |
| 119 | client.releaseDocument("doc-a"); |
| 120 | eq(sentAt(worker, 4).op, "release", "unmounted document releases worker-owned state"); |
| 121 | } |
| 122 | |
| 123 | // ── a superseded live document drops stale output without respawning worker ─ |
| 124 | { |
| 125 | const worker = new FakeWorker(); |
| 126 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 127 | const stale = client.parseDocument("doc-live", "one", { priority: "interactive" }); |
| 128 | await tick(); |
| 129 | const first = sentAt(worker, 0); |
| 130 | stale.cancel(); |
| 131 | eq(await stale.promise, undefined, "superseded document parse settles quietly"); |
| 132 | const current = client.parseDocument("doc-live", "one two", { priority: "interactive" }); |
| 133 | eq(worker.terminated, 0, "superseding a live document keeps the worker alive"); |
| 134 | worker.respond(first.id, RESULT); |
| 135 | await tick(); |
| 136 | const second = sentAt(worker, 1); |
| 137 | eq(second.op, "append", "newest snapshot resumes from worker-owned prefix"); |
| 138 | worker.respond(second.id, RESULT); |
| 139 | eq(await current.promise, RESULT, "newest live parse publishes normally"); |
| 140 | } |
| 141 | |
| 142 | // ── interactive work overtakes queued background history ─────────────────── |
| 143 | { |
| 144 | const worker = new FakeWorker(); |
| 145 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 146 | const active = client.parse("active"); |
| 147 | await tick(); |
| 148 | const background = client.parseDocument("doc-bg", "background", { priority: "background" }); |
| 149 | const interactive = client.parseDocument("doc-live", "interactive", { priority: "interactive" }); |
| 150 | worker.respond(sentAt(worker, 0).id, RESULT); |
| 151 | await active.promise; |
| 152 | await tick(); |
| 153 | const prioritized = sentAt(worker, 1); |
| 154 | eq("documentId" in prioritized ? prioritized.documentId : undefined, "doc-live", "interactive document overtakes background parse"); |
| 155 | worker.respond(prioritized.id, RESULT); |
| 156 | await interactive.promise; |
| 157 | await tick(); |
| 158 | worker.respond(sentAt(worker, 2).id, RESULT); |
| 159 | await background.promise; |
| 160 | } |
| 161 | |
| 162 | // ── cancellation drops the stale response ──────────────────────────────────── |
| 163 | { |
| 164 | const worker = new FakeWorker(); |
| 165 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 166 | const handle = client.parse("stale"); |
| 167 | await tick(); |
| 168 | handle.cancel(); |
| 169 | const cancelled = await handle.promise; |
| 170 | eq(cancelled, undefined, "cancelled parse resolves undefined"); |
| 171 | eq(worker.terminated, 1, "cancelling active work terminates the stale parser"); |
| 172 | worker.respond(worker.sent[0].id, RESULT); // late response for a dead id |
| 173 | await tick(); |
| 174 | eq(client.pendingCount, 0, "late response for a cancelled id is dropped"); |
| 175 | } |
| 176 | |
| 177 | // ── cancel while the worker chunk is still loading ─────────────────────────── |
| 178 | { |
| 179 | let releaseWorker: (worker: FakeWorker) => void = () => {}; |
| 180 | const workerPromise = new Promise<FakeWorker>((resolve) => { |
| 181 | releaseWorker = resolve; |
| 182 | }); |
| 183 | const client = new MarkdownWorkerClient({ createWorker: () => workerPromise }); |
| 184 | const handle = client.parse("early cancel"); |
| 185 | handle.cancel(); |
| 186 | releaseWorker(new FakeWorker()); |
| 187 | eq(await handle.promise, undefined, "parse cancelled during worker startup resolves undefined"); |
| 188 | await tick(); |
| 189 | eq(client.pendingCount, 0, "no pending entry survives an early cancel"); |
| 190 | } |
| 191 | |
| 192 | // ── worker error rejects (callers fall back main-thread) ───────────────────── |
| 193 | { |
| 194 | const worker = new FakeWorker(); |
| 195 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 196 | const handle = client.parse("boom"); |
| 197 | await tick(); |
| 198 | worker.fail(worker.sent[0].id, "parse exploded"); |
| 199 | const message = await handle.promise.then( |
| 200 | () => "resolved", |
| 201 | (error: Error) => error.message, |
| 202 | ); |
| 203 | eq(message, "parse exploded", "worker parse error rejects with its message"); |
| 204 | eq(client.pendingCount, 0, "pending map drains after an error"); |
| 205 | } |
| 206 | |
| 207 | // ── worker crash rejects stranded requests, next parse retries ─────────────── |
| 208 | { |
| 209 | const worker = new FakeWorker(); |
| 210 | let creations = 0; |
| 211 | const client = new MarkdownWorkerClient({ |
| 212 | createWorker: () => { |
| 213 | creations += 1; |
| 214 | return Promise.resolve(worker); |
| 215 | }, |
| 216 | }); |
| 217 | const handle = client.parse("stranded"); |
| 218 | await tick(); |
| 219 | worker.crash(); |
| 220 | const message = await handle.promise.then( |
| 221 | () => "resolved", |
| 222 | (error: Error) => error.message, |
| 223 | ); |
| 224 | eq(message, "markdown worker failed", "crashed worker rejects stranded requests"); |
| 225 | const retry = client.parse("again"); |
| 226 | await tick(); |
| 227 | eq(creations, 2, "a fresh parse recreates the worker after a crash"); |
| 228 | worker.respond(worker.sent[worker.sent.length - 1].id, RESULT); |
| 229 | eq(await retry.promise, RESULT, "recreated worker serves the retry"); |
| 230 | } |
| 231 | |
| 232 | // ── in-process fallback when Worker is unavailable ─────────────────────────── |
| 233 | { |
| 234 | delete (globalThis as { Worker?: unknown }).Worker; |
| 235 | const seen: string[] = []; |
| 236 | const client = new MarkdownWorkerClient({ |
| 237 | parseInProcess: (text) => { |
| 238 | seen.push(text); |
| 239 | return RESULT; |
| 240 | }, |
| 241 | }); |
| 242 | const blocks = await client.parse("fallback text").promise; |
| 243 | eq(blocks, RESULT, "fallback resolves the parse result without a Worker"); |
| 244 | eq(seen.join(","), "fallback text", "fallback receives the exact source text"); |
| 245 | (globalThis as { Worker?: unknown }).Worker = class {}; |
| 246 | } |
| 247 | |
| 248 | // ── dispose settles pending work and terminates the worker ─────────────────── |
| 249 | { |
| 250 | const worker = new FakeWorker(); |
| 251 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 252 | const first = client.parse("one"); |
| 253 | const second = client.parse("two"); |
| 254 | await tick(); |
| 255 | client.dispose(); |
| 256 | eq(await first.promise, undefined, "dispose settles a pending request (1)"); |
| 257 | eq(await second.promise, undefined, "dispose settles a pending request (2)"); |
| 258 | eq(worker.terminated, 1, "dispose terminates the worker"); |
| 259 | eq(client.pendingCount, 0, "dispose drains the pending map"); |
| 260 | const after = await client.parse("post-dispose").promise; |
| 261 | eq(after, undefined, "parse after dispose resolves undefined immediately"); |
| 262 | } |
| 263 | |
| 264 | // ── pending-map hygiene across 100 cycles ──────────────────────────────────── |
| 265 | { |
| 266 | const worker = new FakeWorker(); |
| 267 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 268 | const unhandled: unknown[] = []; |
| 269 | const onUnhandled = (reason: unknown) => unhandled.push(reason); |
| 270 | process.on("unhandledRejection", onUnhandled); |
| 271 | try { |
| 272 | for (let cycle = 0; cycle < 100; cycle += 1) { |
| 273 | const handle = client.parse(`cycle ${cycle}`); |
| 274 | await tick(); |
| 275 | const id = worker.sent[worker.sent.length - 1].id; |
| 276 | if (cycle % 3 === 0) { |
| 277 | handle.cancel(); |
| 278 | worker.respond(id, RESULT); // dropped |
| 279 | } else if (cycle % 3 === 1) { |
| 280 | worker.respond(id, RESULT); |
| 281 | } else { |
| 282 | worker.fail(id, `error ${cycle}`); |
| 283 | } |
| 284 | await handle.promise.catch(() => {}); |
| 285 | } |
| 286 | await tick(); |
| 287 | eq(client.pendingCount, 0, "no pending-request growth across 100 mixed cycles"); |
| 288 | eq(unhandled.length, 0, "no unhandled rejections across 100 mixed cycles"); |
| 289 | eq(worker.sent.length, 100, "every cycle issued exactly one request"); |
| 290 | } finally { |
| 291 | process.off("unhandledRejection", onUnhandled); |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | // ── request ids are monotonic ──────────────────────────────────────────────── |
| 296 | { |
| 297 | const worker = new FakeWorker(); |
| 298 | const client = new MarkdownWorkerClient({ createWorker: () => Promise.resolve(worker) }); |
| 299 | const a = client.parse("a"); |
| 300 | const b = client.parse("b"); |
| 301 | await tick(); |
| 302 | eq(worker.sent.length, 1, "worker queue runs only one parse at a time"); |
| 303 | worker.respond(worker.sent[0].id, RESULT); |
| 304 | await a.promise; |
| 305 | await tick(); |
| 306 | ok(worker.sent[1].id > worker.sent[0].id, "request ids increase monotonically"); |
| 307 | client.dispose(); |
| 308 | await b.promise; |
| 309 | } |
| 310 | |
| 311 | console.log(`\n${passed} passed, ${failed} failed, ${passed + failed} total`); |
| 312 | if (failed > 0) process.exit(1); |
| 313 |