Throwing 'You are importing a file after the Jest environment has been torn down'

Node
1

Hello Internet,

I am taking Mosh’s node.js course and now learning automated testing. While doing so, an error came at random.

Here is a shortened version of the error:

ReferenceError: You are importing a file after the Jest environment has been torn down.
    at (Stack Trace)

Followed by:

TypeError: Right-hand side of instanceof is not callable
    at (Stack Trace)

It’s strange because all my tests are passing, and when I introduce a bug in my code they still pass.

I’m using windows with node 14.15.4 and npm 6.14.10 and testing environment is set to node.

Here is my complete testing code.

2

Could you please share the full error log? Is it pointing to some file (particularly in your project)?

3

Sure,

Jest has detected the following 1 open handle potentially keeping Jest from exiting:

  ●  TCPSERVERWRAP

       9 | const port = process.env.PORT || 3000
      10 | 
    > 11 | module.exports = app.listen(port, () => logger.info(`Listening on port ${port}`))
         |                      ^
      12 | 

      at Function.listen (node_modules/express/lib/application.js:618:24)
      at Object.<anonymous> (index.js:11:22)


ReferenceError: You are trying to `import` a file after the Jest environment has been torn down.

      at BufferList.Readable (node_modules/readable-stream/lib/_stream_readable.js:179:22)
      at BufferList.Duplex (node_modules/readable-stream/lib/_stream_duplex.js:67:12)
      at new BufferList (node_modules/bl/bl.js:33:16)
      at new MessageStream (node_modules/mongoose/node_modules/mongodb/lib/cmap/message_stream.js:35:21)       
      at new Connection (node_modules/mongoose/node_modules/mongodb/lib/cmap/connection.js:54:28)
D:\Ethan\Coding\Node\vidly\node_modules\readable-stream\lib\_stream_readable.js:111
  var isDuplex = stream instanceof Duplex;
                        ^

TypeError: Right-hand side of 'instanceof' is not callable
    at new ReadableState (D:\Ethan\Coding\Node\vidly\node_modules\readable-stream\lib\_stream_readable.js:111:25)
    at BufferList.Readable (D:\Ethan\Coding\Node\vidly\node_modules\readable-stream\lib\_stream_readable.js:183:25)
    at BufferList.Duplex (D:\Ethan\Coding\Node\vidly\node_modules\readable-stream\lib\_stream_duplex.js:67:12) 
    at new BufferList (D:\Ethan\Coding\Node\vidly\node_modules\bl\bl.js:33:16)
    at new MessageStream (D:\Ethan\Coding\Node\vidly\node_modules\mongoose\node_modules\mongodb\lib\cmap\message_stream.js:35:21)
    at new Connection (D:\Ethan\Coding\Node\vidly\node_modules\mongoose\node_modules\mongodb\lib\cmap\connection.js:54:28)
    at D:\Ethan\Coding\Node\vidly\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:36:29
    at callback (D:\Ethan\Coding\Node\vidly\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:280:5)
    at Socket.connectHandler (D:\Ethan\Coding\Node\vidly\node_modules\mongoose\node_modules\mongodb\lib\core\connection\connect.js:325:5)
    at Object.onceWrapper (events.js:421:28)
    at Socket.emit (events.js:315:20)
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1132:10)
npm ERR! Test failed.  See above for more details.
4

There seems to be an issue with app.close(). You might not be closing it in some case.

Please share the beforeEach, beforeAll, afterEach, afterAll of your test files.