Strategia testowa vs plan testowy

Test strategy is a set of instructions 
which explain the test design  and determine
how the test should be performed.
Test strategy has the essential objectives of
what approach to take and which module to check.

Test plan is a document for a software project
which has the approach, scope
on the work of software testing.
Also A test plan has the essential objective of
how to test, when to test 
and who will confirm it.
Obedient Ocelot