The Test Engineer is expected to understand the software requirement specifications for the product that she/he is assigned to Test.
This Testing could be for entirely for new modules or for enhancements done to the pre-existing features / modules.
The Test Engineer must also make sure that the documentation of the product is in sync with the software so as to adhere to the defined overall feature / product release schedules.
Module level testing, Integration testing, System testing, Performance testing need to done as assigned by the Test Lead.