environment test not set when configuring polly without --environment=test

Hello

I have added pollyjs to my project

```js
// config/polly.js
module.exports = function (env) {
return {
// Addon Configuration Options
enabled: env === 'test',
};
};
```

but it is not enabled. I have to put --environment=test in the command line

yarn ember test --server works good
yarn ember exam --environment=test --server --random works good
yarn ember exam --server --random failed