test: stabilize gateway restart loop signals

src/cli/gateway-cli/run-loop.test.ts

@@ -241,20 +241,6 @@ async function waitForStart(started: Promise<void>) {
   await new Promise<void>((resolve) => setImmediate(resolve));
 }
 
-async function waitForAssertion(assertion: () => void, maxTicks = 20) {
-  for (let tick = 0; tick < maxTicks; tick += 1) {
-    try {
-      assertion();
-      return;
-    } catch (err) {
-      if (tick === maxTicks - 1) {
-        throw err;
-      }
-      await new Promise<void>((resolve) => setImmediate(resolve));
-    }
-  }
-}
-
 async function createSignaledLoopHarness(exitCallOrder?: string[]) {
   const close = vi.fn(async () => {});
   const { start, started } = createSignaledStart(close);
@@ -292,10 +278,17 @@ describe("runGatewayLoop", () => {
       const closeFirst = vi.fn(async () => {});
       const closeSecond = vi.fn(async () => {});
       const { runtime, exited } = createRuntimeWithExitSignal();
+      let resolveSecond: (() => void) | null = null;
+      const startedSecond = new Promise<void>((resolve) => {
+        resolveSecond = resolve;
+      });
       const start = vi
         .fn()
         .mockResolvedValueOnce({ close: closeFirst })
-        .mockResolvedValueOnce({ close: closeSecond });
+        .mockImplementationOnce(async () => {
+          resolveSecond?.();
+          return { close: closeSecond };
+        });
       const { runGatewayLoop } = await import("./run-loop.js");
       void runGatewayLoop({
         start: start as unknown as Parameters<typeof runGatewayLoop>[0]["start"],
@@ -316,7 +309,9 @@ describe("runGatewayLoop", () => {
         reason: "gateway restarting",
         restartExpectedMs: 1500,
       });
-      await waitForAssertion(() => expect(start).toHaveBeenCalledTimes(2));
+      await startedSecond;
+      expect(start).toHaveBeenCalledTimes(2);
+      await new Promise<void>((resolve) => setImmediate(resolve));
 
       sigint();
       await expect(exited).resolves.toBe(0);