Test library scope

Test library scope
Libraries implemented as classes can have an internal state, which can be altered by keywords and with arguments to the constructor of the library. Because the state can affect how keywords actually behave, it is important to make sure that changes in one test case do not accidentally affect other test cases. These kind of dependencies may create hard-to-debug problems, for example, when new test cases are added and they use the library inconsistently.
Robot Framework attempts to keep test cases independent from each other: by default, it creates new instances of test libraries for every test case. However, this behavior is not always desirable, because sometimes test cases should be able to share a common state. Additionally, all libraries do not have a state and creating new instances of them is simply not needed.
Test libraries can control when new libraries are created with a class attribute ROBOT_LIBRARY_SCOPE . This attribute must be a string and it can have the following three values:
Default scope of robot library is test case. The library is initialized once per test cases.
If we set scope as TEST SUITE, the library is initialized once per test suite.
ROBOT_LIBRARY_SCOPE = ‘TEST SUITE’