perf(web): add idempotent batch verification fast paths

web/tests/unit/wbv2-fast-paths.test.mjs

@@ -0,0 +1,48 @@
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import test from "node:test";
+
+import {
+  adaptiveBatchSize,
+  batchContract,
+  commandBudget,
+  completedBatch,
+} from "../../../tools/web/wbv2-batch-contract.mjs";
+import { createFailureLedgerSession } from "../../../tools/web/wbv2-failure-ledger.mjs";
+
+test("batch contract is stable and completion is idempotent", () => {
+  const module = { moduleId: "FCURVE", coverageBindings: ["rna:a", "rna:b"] };
+  const contract = batchContract("WBV2-P1-001", module);
+  assert.equal(contract.selectedCount, 2);
+  assert.match(contract.batchId, /^WBV2-P1-001:FCURVE:[a-f0-9]{16}$/u);
+  assert.equal(completedBatch({ status: "done", batchId: contract.batchId, selectedRecordIds: contract.selectedRecordIds }, "WBV2-P1-001", module), true);
+});
+
+test("adaptive batches follow the three-cycle fast and slow paths", () => {
+  assert.equal(adaptiveBatchSize({ currentSize: 24, maxSize: 32, history: [{ durationMs: 120_000, commands: 10, focusedGateFailure: false }] }), 28);
+  assert.equal(adaptiveBatchSize({ currentSize: 24, maxSize: 32, history: [{ durationMs: 901_000, commands: 10 }] }), 12);
+  assert.equal(adaptiveBatchSize({ currentSize: 24, maxSize: 32, remaining: 5, history: [] }), 5);
+});
+
+test("command budget separates exploration from execution", () => {
+  assert.equal(commandBudget(["cat file", "npm run build"]).withinBudget, true);
+  assert.equal(commandBudget(Array.from({ length: 49 }, () => "npm run focused")).withinBudget, false);
+  assert.equal(commandBudget(Array.from({ length: 17 }, () => "rg pattern")).withinBudget, false);
+});
+
+test("failure ledger hydrates completed cycles and flushes once", () => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "wbv2-fast-path-ledger-"));
+  const logPath = "tests/golden/WBV2/cycle.log";
+  fs.mkdirSync(path.dirname(path.join(root, logPath)), { recursive: true });
+  fs.writeFileSync(path.join(root, logPath), 'prefix {"event":"cycle.completed","failure":{"task":"T","phase":"gate","reason":"failed"}}\n');
+  const session = createFailureLedgerSession(root, { logPaths: [logPath] });
+  assert.equal(session.ledger.entries.length, 1);
+  session.record({ task: "T2", phase: "gate", reason: "failed" });
+  assert.equal(fs.existsSync(path.join(root, "tests/golden/WBV2/failure-ledger.json")), false);
+  session.flush();
+  const written = JSON.parse(fs.readFileSync(path.join(root, "tests/golden/WBV2/failure-ledger.json"), "utf8"));
+  assert.equal(written.entries.length, 2);
+  assert.deepEqual(written.hydratedLogs, [logPath]);
+});