Discussion on: Testing Node.js + Mongoose with an in-memory database

[Paula Santamaría]

🤔 looks like MongoMemoryServer is trying to download a binary for the default MongoDB version that is compatible with the OS running on your CircleCI server/container but can't find it.

I've never worked with CircleCI but I'd recommend you to check if the MongoDB version that MongoMemoryServer is trying to download is available for your OS & architecture.
Here's the code where the download URL for the binaries is generated, in case you want to check that out: MongoBinaryDownloadUrl.

Maybe you can set a specific version of MongoDB that exists for your platform, like this:

    mongod = await MongoMemoryServer.create({ binary: { version: '4.2.6' } });
    const uri = await mongod.getConnectionString();

Another way to go would be to activate debug mode so you can get more info on the error. Just set the debug option to "1" in the package.json config section. More info here

[Kowshik Sundararajan]

Thanks for the suggestion, Paula. I found that for my circleci build, specifying a version like 4.2.6 did not work but specifying latest worked.

Hope that helps!