Starting the MongoMemoryServer Instance failed || Error: spawn Unknown system error -86

Question

`I am tested my node.js microservices using Jest, supertest and using mongodb-memory-server for storage. I have written the config files as per the latest guides of jest and mongodb-memory-server but once I start the Test, I am getting below Error.

**Starting the MongoMemoryServer Instance failed**, enable debug log for more information. Error:
# **Error: spawn Unknown system error -86**
        at ChildProcess.spawn (node:internal/child_process:413:11)
        at spawn (node:child_process:757:9)
        at MongoInstance._launchMongod (/Users/aadilnabi/web/microservices/ticketing/auth/node_modules/mongodb-memory-server-core/src/util/MongoInstance.ts:474:31)
        at MongoInstance.<anonymous> (/Users/aadilnabi/web/microservices/ticketing/auth/node_modules/mongodb-memory-server-core/src/util/MongoInstance.ts:376:31)
        at Generator.next (<anonymous>)
        at fulfilled (/Users/aadilnabi/web/microservices/ticketing/auth/node_modules/tslib/tslib.js:164:62) {
      errno: -86,
      code: 'Unknown system error -86',
      syscall: 'spawn'
    }

      at MongoMemoryServer.<anonymous> (node_modules/mongodb-memory-server-core/src/MongoMemoryServer.ts:293:17)
      at node_modules/tslib/tslib.js:167:75
      at __awaiter (node_modules/tslib/tslib.js:163:16)
      at node_modules/mongodb-memory-server-core/src/MongoMemoryServer.ts:284:68

 FAIL  src/routes/__test__/signup.test.ts
  ✕ returns 201 on a successful signup

  ● returns 201 on a successful signup

    spawn Unknown system error -86

      at MongoInstance._launchMongod (node_modules/mongodb-memory-server-core/src/util/MongoInstance.ts:474:31)
      at MongoInstance.<anonymous> (node_modules/mongodb-memory-server-core/src/util/MongoInstance.ts:376:31)
      at fulfilled (node_modules/tslib/tslib.js:164:62)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        2.21 s
Ran all test suites.

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/Users/aadilnabi/web/microservices/ticketing/auth/node_modules/mongodb-memory-server-core/lib/util/MongoInstance.js:150
                    const err = new errors_1.GenericMMSError(`Instance failed to start within ${timeoutTime}ms`);
                                ^

GenericMMSError: **Instance failed to start within 10000ms**
    at Timeout.<anonymous> (/Users/aadilnabi/web/microservices/ticketing/auth/node_modules/mongodb-memory-server-core/src/util/MongoInstance.ts:365:21)
    at listOnTimeout (node:internal/timers:569:17)
    at processTimers (node:internal/timers:512:7)

Node.js v18.14.2

My dev dependecies are as below:

"devDependencies": {
    "@types/jest": "^29.5.0",
    "@types/supertest": "^2.0.12",
    "jest": "^29.5.0",
    "mongodb-memory-server": "^8.12.2",
    "supertest": "^6.3.3",
    "ts-jest": "^29.1.0"
  }

Config file (setup.ts) contains below:

jest.setTimeout(10000);

  mongo = await MongoMemoryServer.create();
  const mongoUri = mongo.getUri();

  await mongoose.connect(mongoUri);
});

beforeEach(async () => {
  const collections = await mongoose.connection.db.collections();
  for (let collection of collections) {
    await collection.deleteMany({});
  }
});

afterAll(async () => {
  if (mongo) {
    await mongo.stop();
  }
  await mongoose.connection.close();
});

Answer 1

Solution:

Looks like Mongodb-memory-server needs Rosetta 2 on Mac OS. Once I installed Rosetta on my Mac, it solved this issue and I was able to perform my test successfully.