What is a test net?

[armin]

The testnet is a safe version of the Bitshares ecosystem where the actions you take do not involve real money. Usually it's used for testing new software or trying out features of Bitshares before doing them on the mainnet

[Bangzi]

I read everywhere about "test net", "launch of the test net", "waiting for the test net" etc etc. What does it is?

Testnet - For Testing Purpose
https://testnet.bitshares.eu/

[Parishy]

I read everywhere about "test net", "launch of the test net", "waiting for the test net" etc etc. What does it is?