Public test server: Singularity
The public test server, Singularity (or Sisi), is open to all players. It's purpose is to try out new features, normally the next major patch for Tranquility will be tested on this server. Character information is replicated (=mirrored) to the Singularity server every few months, but keep in mind that if your account got created after the last replication, you will not be able to access the server.
Gameplay mechanics and playing environments may be quite different from what you're used to on Tranquility. Here, the world is constantly changing.
Details and instructions for accessing Singularity can be found on the Singularity page.
Semi-public test server: Duality
Duality is a semi-public test server for EVE Online that is used by both CCP developers and EVE players to test changes and new features before they are released to the Tranquility server. Duality differs from Singularity in that it is an event server, meaning that it is focused on organized events like mass tests and playtests coordinated by CCP. Only during this events is Duality available to players, the rest of the time it will be in VIP mode and only CCP developers and ISD BH volunteers will be able to access it. In some cases Duality will be very close to Tranquility (maybe running even the same client), for example when testing server code changes in a mass test, in other cases it might be used to test features, which are still months from being published to Tranquility.
Details and instructions for accessing Duality can be found on the Duality page.
Test server rules
Non-public test servers
CCP operates several other test server beside Singularity and Duality, but these additional test server are not accessible by the public. Most of them are for developing and testing new features, while several other servers run older versions of EVE and are used for reference (for example to verify when specific bug was introduced).
Well-known non-public test servers:
Top Contributors For This Page