When the build is ready to be tested then u need to test 
the product, this product will be implemented somewhere may 
be a dummy environment similar to as that of the real 
environment and u wil need to test the product here, so 
this env is ur test environment.
Test set up is all the data preparation and all the things 
u need to do to before u start the testing, so its a set-up 
before ur testing for the testing which u will be doing.

Test environment is a simulted in house production 
environment where a build is tested before handedover to 
the client.

Test setup  includes all arrangements including test plans, 
test scenarios, test suites & test cases and all the 
relevent documentation required for testing.