  Context: Albeit different approaches exist for automated GUI testing of
hybrid mobile applications, the practice appears to be not so commonly adopted
by developers. A possible reason for such a low diffusion can be the fragility
of the techniques, i.e. the frequent need for maintaining test cases when the
GUI of the app is changed.
  Goal: In this paper, we perform an assessment of the maintenance needed by
test cases for a hybrid mobile app, and the related fragility causes.
  Methods: We evaluated a small test suite with a Layout-based testing tool
(Appium) and a Visual one (EyeAutomate) and observed the changes needed by
tests during the co-evolution with the GUI of the app.
  Results: We found that 20% Layout-based test methods and 30% Visual test
methods had to be modified at least once, and that each release induced
fragilities in 3-4% of the test methods.
  Conclusion: Fragility of GUI tests can induce relevant maintenance efforts in
test suites of large applications. Several principal causes for fragilities
have been identified for the tested hybrid application, and guidelines for
developers are deduced from them.
