Client
Everybody knows that testing is a process that produces and consumes large amounts of data. Data used in testing describes the initial conditions for a test and represents the medium through which the tester influences the software. It is a crucial part of most Functional Tests.
Depending on your testing environment you may need to CREATE Test Data (Most of the times) or at least identify a suitable test data for your test cases (is the test data is already created).
Typically test data is created in-sync with the test case it is intended to be used for.