test: replace slow gateway SIGTERM integration coverage

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

@@ -91,6 +91,42 @@ function createRuntimeWithExitSignal(exitCallOrder?: string[]) {
 }
 
 describe("runGatewayLoop", () => {
+  it("exits 0 on SIGTERM after graceful close", async () => {
+    vi.clearAllMocks();
+
+    await withIsolatedSignals(async () => {
+      const close = vi.fn(async () => {});
+      let resolveStarted: (() => void) | null = null;
+      const started = new Promise<void>((resolve) => {
+        resolveStarted = resolve;
+      });
+      const start = vi.fn(async () => {
+        resolveStarted?.();
+        return { close };
+      });
+      const { runtime, exited } = createRuntimeWithExitSignal();
+
+      vi.resetModules();
+      const { runGatewayLoop } = await import("./run-loop.js");
+      const _loopPromise = runGatewayLoop({
+        start: start as unknown as Parameters<typeof runGatewayLoop>[0]["start"],
+        runtime: runtime as unknown as Parameters<typeof runGatewayLoop>[0]["runtime"],
+      });
+
+      await started;
+      await new Promise<void>((resolve) => setImmediate(resolve));
+
+      process.emit("SIGTERM");
+
+      await expect(exited).resolves.toBe(0);
+      expect(close).toHaveBeenCalledWith({
+        reason: "gateway stopping",
+        restartExpectedMs: null,
+      });
+      expect(runtime.exit).toHaveBeenCalledWith(0);
+    });
+  });
+
   it("restarts after SIGUSR1 even when drain times out, and resets lanes for the new iteration", async () => {
     vi.clearAllMocks();