Andrew Mead expensify: test(jest) passes for any value(object) inside the toEqual argument?

This is my action generators:

export const addExpense = (expense) => ({
type: "ADD_EXPENSE",
expense,
});

export const startAddExpense = (expenseData={}) => {
return (dispatch) => {
const {
  description = "no description",
  note = "empty",
  amount = 0,
  createdOn = 0,
} = expenseData;
const expense = { description, note, amount, createdOn };
return database
  .ref("expenses")
  .push(expense)
  .then((ref) => {
    dispatch(
      addExpense({
        id: ref.key,
        ...expense,
      })
    );
  });
 };
};

Now my jest testing for startAddExpense action generator is:

test("startAddExpense: should add expense to database and store", (done) => {
const store = createMockStore({});
const expenseData = {
  description: "Mouse",
  amount: 3000,
  note: "This one is better",
  createdOn: 1000,
};

store
 .dispatch(startAddExpense(expenseData))
 .then(() => {
   const actions = store.getActions();
   // expect(actions[0]).toEqual({});
   //OR
   expect(actions[0]).toEqual({
     type: "ADD_EXPENSE",
     expense: {
       id: expect.any(String),
       ...expenseData,
     },
   });
   return database.ref(`expenses/${actions[0].expense.id}`).once("value");
 })
.then((dataSnapShot) => {
  // expect(dataSnapShot.val()).toEqual({});
  //OR
  expect(dataSnapShot.val()).toEqual({
    id: expect.any(String),
    ...expenseData,
  });
 });
done();
});

My question is why does the test(jest) passes for any value(object) inside the toEqual argument of both action[0] and dataSnapShot.val()??

You can see that in the above case,once i have passed an empty object(which has been muted) and another time i have passed the expected object, but the test passes for both the case. I even tried puuting any key-value pair inside the object and it still passes the test???