Cannot log after tests are done in jestjs

I was using the react-native default test case (see below) when Cannot log after tests are done happened.

it('renders correctly', () => {
  renderer.create(<App />);
});

Apparently, the problem was that the test ended but logging was still needed. So I tried to make the callback in the test case async, hoping that the test won't terminate immediately:

it('renders correctly', async () => {
  renderer.create(<App />);
});

And it worked. However, I have very little clue what the inner working is.

If you are using async/await type in your code, then this error can occur when you are calling async function without await keyword.

In my case, I have defined a function like this below,

async getStatistics(headers) {
    ....
    ....
    return response;
}

But I have called this method like getStatistics(headers) instead of await getStatistics(headers).

When I included await, it worked fine and the issue resolved.

In my case while using nodejs + jest + supertest the problem was that when I import app from "./app" to my test file to do some stuff with supertest (request(app)), I actually import with app.listen() , because when I'm exporting app, export takes in account app.listen() too, but we don't need app.listen() in tests and it throws an error

"Cannot log after tests are done.Did you forget to wait for something async in your test?"

Here is all in one file(that's the problem!)

const app = express();

app.use(express.json());

// ROUTES
app.get("/api", (req, res) => {
    res.json({ message: "Welcome to Blog API!" });
});

app.use("/api/users", usersRoutes);
app.use("/api/blogs", blogsRouter);

// The server will start only if the connection to database is established
mongoose
    .connect(process.env.MONGO_URI!)
    .then(() => {
        console.log("MongoDB est connecté");

        const port = process.env.PORT || 4000;
        app.listen(port, () => console.log(`The server is running on port: ${port}`));
    })
    .catch(err => {
        console.log(err);
    });

export default app;

To solve this issue I created 2 separate folders:

// 1) app.ts

Where I put all stuff for my const app = express(), routes etc and export app

dotenv.config();

const app = express();

app.use(express.json());

// ROUTES
app.get("/api", (req, res) => {
    res.json({ message: "Welcome to Blog API!" });
});

app.use("/api/users", usersRoutes);
app.use("/api/blogs", blogsRouter);

export default app;

// 2) index.ts

Where I put app.listen() and mongoose.connection() and import app

import mongoose from "mongoose";
import app from "./app";

// The server will start only if the connection to database is established

mongoose
    .connect(process.env.MONGO_URI!)
    .then(() => {
        console.log("MongoDB est connecté");

        const port = process.env.PORT || 4000;
        app.listen(port, () => console.log(`The server is running on port: ${port}`));
    })
    .catch(err => {
        console.log(err);
    });

For me I needed to add an await before the expect() call also to stop this error (and an async before the test() callback function).

Also caused and fixed Jest not detecting coverage on the lines in the code throwing the error!

test("expect error to be thrown for incorrect request", async () => {
  await expect(
  // ^ added this
    async () => await getData("i-made-this-up")
  ).rejects.toThrow(
    "[API] Not recognised: i-made-this-up"
  );
});

getData() returns an Axios call and in this case an error is caught by catch and re-thrown.

const getData = async (id) => {
  return await axios
    .get(`https://api.com/some/path?id=${id}`)
    .then((response) => response.data)
    .catch((error) => {
      if (error?.response?.data?.message) {
        console.error(error) // Triggered the error
        throw new Error("[API] " + error.response.data.message);
      }

      throw error;
    });
};

This happened to me because I had an infinite loop while (true). In my case, I was able to add a method for setting the value of the loop based on user input, rather than defaulting to true.

I solved it with the env variables:

if (process.env.NODE_ENV !== 'test') {
  db.init().then(() => {
    app.listen(PORT, () => {
      console.log('API lista por el puerto ', PORT)
    })
  }).catch((err) => {
    console.error(err)
    process.exit(1)
  })
} else {
  module.export = app
}

In my case, the error was caused by asynchronous Redis connection still online. Just added afterall method to quit Redis and could see the log again.

Working on Typescript 4.4.2:

test("My Test", done => {
    let redisUtil: RedisUtil = new RedisUtil();
    let redisClient: Redis = redisUtil.redis_client();
    done();
});

afterAll(() => {
    redisClient.quit();
});

Also don't forget to extend your timeout if you have a long running test using

jest.setTimeout();

In my case I'm paging through API calls and logging so it will extend after jest's default timeout, which is why I was getting the error.

I had a similar issue:

Cannot log after tests are done. Did you forget to wait for something async in your test?
Attempted to log "Warning: You seem to have overlapping act() calls, this is not supported. Be sure to await previous act() calls before making a new one. ".

It was due to a missing static keyword. This code caused the issue:

class MyComponent extends React.Component<Props, State> {
  propTypes = {
    onDestroy: PropTypes.func,
  }
}

It should have been:

class MyComponent extends React.Component<Props, State> {
  static propTypes = {
    onDestroy: PropTypes.func,
  }
}

I faced same warnings. However the fix is bit weird:

The jest unit test script import a function (which is not export from src/). After I added the export to the function to be tested. The error disappears.

In my case I had to just increase the default timeout for it function

it("Your tests", async () => {
    // your tests  
}, 100000);

I also had a somewhat slightly noticeable timeout error above the Cannot log after tests are done. errors:

thrown: "Exceeded timeout of 5000 ms for a test.
Add a timeout value to this test to increase the timeout, if this is a long-running test. See https://jestjs.io/docs/api#testname-fn-timeout."