Cannot log after tests are done.

Os meus testes passam mas mesmo assim continua tendo um erro mesmo eu ajustando meu código para estar exatamente igual o da instrutora.

Eu não mexi em nada do código original, apenas fiz o teste como na aula.

import Transacao from "./Transacao";
import React from "react";
import { render } from "@testing-library/react";

describe("Componente de transação do extrato", () => {
    it("O snapshot do componente deve permanecer sempre o mesmo", () => {
        const { container } = render(
            <Transacao data="08/09/2020" tipo="saque" valor="20.00" />
        );
        expect(container.firstChild).toMatchSnapshot();
    });
});

ERRO

PASS  src/transacoes/Transacao.test.js
 PASS  src/App.test.js

Test Suites: 2 passed, 2 total
Tests:       6 passed, 6 total
Snapshots:   1 passed, 1 total
Time:        1.984s, estimated 2s
Ran all test suites related to changed files.

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  ●  Cannot log after tests are done. Did you forget to wait for something async in your test?
    Attempted to log "Warning: An update to App inside a test was not wrapped in act(...).

    When testing, code that causes React state updates should be wrapped into act(...):

    act(() => {
      /* fire events that update state */
    });
    /* assert on the output */

    This ensures that you're testing the behavior the user would see in the browser. Learn more at https://fb.me/react-wrap-tests-with-act
        in App (at App.test.js:8)".

      38 |   }
      39 | 
    > 40 |   useEffect(() => {
         |     ^
      41 |     obterSaldo();
      42 |     carregarTransacoes();
      43 |   }, [saldo])

      at console.error (node_modules/@jest/console/build/BufferedConsole.js:163:10)
      at printWarning (node_modules/react-dom/cjs/react-dom.development.js:88:30)
      at error (node_modules/react-dom/cjs/react-dom.development.js:60:5)
      at warnIfNotCurrentlyActingUpdatesInDEV (node_modules/react-dom/cjs/react-dom.development.js:23284:7)
      at dispatchAction (node_modules/react-dom/cjs/react-dom.development.js:15656:9)
      at carregarTransacoes (src/App.js:40:5)


  ●  Cannot log after tests are done. Did you forget to wait for something async in your test?
    Attempted to log "Warning: Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in a useEffect cleanup function.
        in App (at App.test.js:8)".

      38 |   }
      39 | 
    > 40 |   useEffect(() => {
         |     ^
      41 |     obterSaldo();
      42 |     carregarTransacoes();
      43 |   }, [saldo])

      at console.error (node_modules/@jest/console/build/BufferedConsole.js:163:10)
      at printWarning (node_modules/react-dom/cjs/react-dom.development.js:88:30)
      at error (node_modules/react-dom/cjs/react-dom.development.js:60:5)
      at warnAboutUpdateOnUnmountedFiberInDEV (node_modules/react-dom/cjs/react-dom.development.js:23161:5)
      at scheduleUpdateOnFiber (node_modules/react-dom/cjs/react-dom.development.js:21169:5)
      at dispatchAction (node_modules/react-dom/cjs/react-dom.development.js:15660:5)
      at carregarTransacoes (src/App.js:40:5)