Test Bed: Test bed means set up to start the testing of an
application such as test environment, list of test cases
going to be executed, build of an application(EXE),test
data(input to test the condition which is to be given by the
client) 

Test Environment: Required hardware and software

Test harness: Test harness means ready to start test
execution or Test Bed plus Test Environment

Sanity Testing:If we receive the initial build for dev team
then we check the build is stable or not
 Eg : if we got the build and check the application is
opened or not 

Smoke Testing: After Receiving the build we have to check
the major functionality of the application is working or not

Eg if we opened the Application and enter the data and 
saved that data taht data saved in back end if we agree that
smoke test is passed so if it is failed report to dev team


Re-Testing:Test the Application on multiple inputs with
multiple test data on the same build

Eg: if we take login id  and password in that we enter with
multiple inputs with multiple test data and test that
Application.

Regression Testing: Implement test cases on modified build

Eg : if we take initial 5 test cases that should be executed
and verify it  2 should be passed and remaining failed and
send the report to failed ones to dev team and again they
fixed send new build for testing and we test all 5 test
cases even though they passed so this process traverses the
all test cases should be passed

thanks for ur answer sir(abcd)