The docs here are as below:
When it comes to unit testing an application, we usually want to avoid making a database connection, keeping our test suites independent and their execution process as fast as possible. But our classes might depend on repositories that are pulled from the connection instance. How do we handle that? The solution is to create mock repositories. In order to achieve that, we set up custom providers. Each registered repository is automatically represented by a Repository token, where EntityName is the name of your entity class.
The @nestjs/typeorm package exposes the getRepositoryToken() function which returns a prepared token based on a given entity.
What does that even mean? Autocomplete docs just give the signature with no explanation.