Group test execution by class in pytest

I have the testcases structured in the following way.

app
  test_login.py
    class1
      test_11
      test_12
  test_function1.py
    class2
      test_21
      test_22

When I run "pytest.exe app", pytest is able to identify all the testcases, but it executes in random order. For example, test11, test22, test12 and so on

Is there any way I can change this and execute all testcases in a file::class first and then move on to another file::class?