return nil
}

// fakeNs is a mock struct for testing
type fakeNs struct {
	closed *atomic.Bool
	fd     uintptr
	inode  uint64
}

func newFakeNs(fd uintptr) *fakeNs {
	// the fake inode is the fd! magic.
	return &fakeNs{closed: &atomic.Bool{}, fd: fd, inode: uint64(fd)}
}

func newFakeNsInode(fd uintptr, inode uint64) *fakeNs {
	return &fakeNs{closed: &atomic.Bool{}, fd: fd, inode: inode}
}

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"

	"istio.io/istio/pkg/test/util/assert"
)

func TestWithProcFs(t *testing.T) {
	n := NewPodNetnsProcFinder(fakeFs())
	pod := &corev1.Pod{ObjectMeta: metav1.ObjectMeta{
		Name:      "foo",
		Namespace: "bar",
		UID:       types.UID("863b91d4-4b68-4efa-917f-4b560e3e86aa"),
	}}

		},
		Spec: corev1.PodSpec{ServiceAccountName: "sa"},
	}

	ztunnelServer.delError = errors.New("fake error")
	// this is usually called after add. so manually add the pod uid for now
	fakens := newFakeNs(123)
	closed := fakens.closed
	workload := WorkloadInfo{
		Workload: podToWorkload(pod),
		Netns:    fakens,
	}
	fixture.podNsMap.UpsertPodCacheWithNetns(string(pod.UID), workload)

	ContainerID: "bbb-eee-www",
}

var (
	fakeIP                 = net.ParseIP("99.9.9.9")
	fakeGW                 = net.ParseIP("88.9.9.9")
	fakeIDX                = 0
	fakePrevResultIPConfig = cniv1.IPConfig{
		Interface: &fakeIDX,
		Address: net.IPNet{
			IP: fakeIP,
		},
		Gateway: fakeGW,
	}
)

func TestPushCNIAddEventSucceed(t *testing.T) {

    class FakeOp implements Runnable {
      final int op;

      FakeOp(int op) {
        this.op = op;
      }

      @Override
      public void run() {
        callOrder.add(op);
      }
    }

    e.execute(new FakeOp(0));
    e.execute(new FakeOp(1));
    e.execute(new FakeOp(2));
    fakePool.runAll();

    class FakeOp implements Runnable {
      final int op;

      FakeOp(int op) {
        this.op = op;
      }

      @Override
      public void run() {
        callOrder.add(op);
      }
    }

    e.execute(new FakeOp(0));
    e.execute(new FakeOp(1));
    e.execute(new FakeOp(2));
    fakePool.runAll();

  }

  // TODO(cpovirk): instead of skipping, use a smaller number of steps
  @GwtIncompatible // works but takes 5 minutes to run
  public void testPeekingIteratorBehavesLikeIteratorOnThreeElementIterable() {
    actsLikeIteratorHelper(Lists.newArrayList("A", "B", "C"));
  }

  @GwtIncompatible // works but takes 5 minutes to run
  public void testPeekingIteratorAcceptsNullElements() {

			Containers: []corev1.Container{app, proxy},
		},
	}

	fakeNS := &corev1.Namespace{
		TypeMeta: metav1.TypeMeta{
			APIVersion: "core/v1",
			Kind:       "Namespace",
		},
		ObjectMeta: metav1.ObjectMeta{
			Name:      testNSName,
			Namespace: "",
			Labels:    map[string]string{},
		},
	}

	return fakePod, fakeNS
}

		fakeCtx,
		pod,
		true,
	).Return(errors.New("fake error"))

	fakeClientSet := fake.NewClientset()

	fakeIPSetDeps := ipset.FakeNLDeps()
	set := ipset.IPSet{V4Name: "foo-v4", Prefix: "foo", Deps: fakeIPSetDeps}

	m := getFakeDPWithIPSet(server, fakeClientSet, set)
	expectPodRemovedFromIPSet(fakeIPSetDeps, pod.Status.PodIPs)

	// pod is not in fake client, so if this will try to remove annotation, it will fail.

This parameter must be something like a function.

You **don't call it** directly (don't add the parenthesis at the end), you just pass it as a parameter to `Depends()`.

And that function takes parameters in the same way that *path operation functions* do.

/// tip

You'll see what other "things", apart from functions, can be used as dependencies in the next chapter.

///