Once uppon a time, at the dawn of the implementation of Storj, when all the nodes are read from the database directly, every time.
After a while -- due to performance reasons -- it has been changed for upload and download: where all the nodes are read for a short period of time, and used from memory.
This is the version which was improved recently to support advanced node selections using placement.
But stil we have an old configuration value `service.config.NodeSelectionCache.Disabled`, and the db based implementation: `service.FindStorageNodesWithPreferences(ctx, req, &service.config.Node)`.
For safety, we need to remove this option, to make sure that we use the cache, which has the advanced features.
This patch was supposed to be a very small one (just removing a method and a config: https://review.dev.storj.io/c/storj/storj/+/11074/1/satellite/overlay/service.go), but it turned out that we need to update a lot of unit tests.
These unit tests used the old implementation (which is not used in production any more).
The tests which used both implementation are just updated to use only the new one
The tests which used only the old implementation are refactored (but keeping the test cases).
Using real unit tests (without DB, working on OSX, fast)
Closes https://github.com/storj/storj/issues/6217
Change-Id: I023f92c7e34235665cf8474513e67b2fcc4763eb
ca0ea50cba