fix(mosaic): de-flake mutator-class lease gate TTL-expiry test (#861)

packages/mosaic/src/mutator-gate/mutator-gate.acceptance.spec.ts

@@ -661,13 +661,27 @@ describe('whole mutator-class lease gate', () => {
   test('observer revocation and monotonic TTL expiry deny the next mutator', async () => {
     const { socket } = await startBroker();
     const sessionId = await register(socket);
-    const pending = await beginVerification(socket, sessionId, 'claude', 1, 1);
-    await promote(socket, sessionId, pending.receipt_challenge!);
 
+    // Establish the lease with a normal (non-racing) TTL first and prove it
+    // authorizes. This "still valid" check is setup, not a TTL-expiry
+    // assertion, so it must not share a lease with a 1-second TTL: on a
+    // contended push-CI host, scheduling delay alone between promote() and
+    // this authorize() call can consume that entire 1-second margin and
+    // spuriously deny it (CI#1945). Using a generous TTL here removes that
+    // real-time race without touching lease-gate security semantics.
+    const pending = await beginVerification(socket, sessionId, 'claude');
+    await promote(socket, sessionId, pending.receipt_challenge!);
     expect(await authorize(socket, sessionId, 'claude', 'Bash')).toMatchObject({
       ok: true,
       decision: 'allow',
     });
+
+    // A dedicated, isolated short-TTL lease drives the deliberate monotonic
+    // expiry demonstration below. It is never used for anything but the
+    // wait-then-expire assertion, so there is no setup work racing its
+    // 1-second window.
+    const shortLived = await beginVerification(socket, sessionId, 'claude', 1, 1, 2);
+    await promote(socket, sessionId, shortLived.receipt_challenge!);
     await new Promise((resolve) => setTimeout(resolve, 1_100));
     expect(await authorize(socket, sessionId, 'claude', 'Bash')).toMatchObject({
       ok: false,
@@ -675,7 +689,7 @@ describe('whole mutator-class lease gate', () => {
       decision: 'deny',
     });
 
-    const refreshed = await beginVerification(socket, sessionId, 'claude', 1, 300, 2);
+    const refreshed = await beginVerification(socket, sessionId, 'claude', 1, 300, 3);
     await promote(socket, sessionId, refreshed.receipt_challenge!);
     expect(
       await request(socket, {