Importing a module does not run the code inside it

问题:

I have a few files with tests and an imported file:

# test1.py
print("running test1.py")

import unittest
import imported

class MyTest1(unittest.TestCase):
    def test_method1(self):
        assert "love" == "".join(["lo", "ve"])

    def test_fail1(self):
        assert True, "I failed!"

and

# test2.py
print("running test2.py")

import unittest
import imported

class MyTest2(unittest.TestCase):
    def test_ok2(self):
        self.assertEqual(True, 2==2, "I will not appear!")

    def test_fail2(self):
        self.assertFalse(False, "Doh!")

and

# imported.py
import sys

# Here I am accessing the module that has imported this file
importing = sys.modules[sys._getframe(6).f_globals['__name__']]
print(importing.__name__ + " imported this file")

When I run pytest -s test1.py test2.py, I get this result:

=============================== test session starts ================================
platform darwin -- Python 3.6.0, pytest-3.7.1, py-1.5.4, pluggy-0.7.1
rootdir: /Users/ibodi/MyDocs/progs/Python/unittest_test, inifile:
collecting 0 items                                                                 running test1.py
test1 imported this file
collecting 2 items                                                                 running test2.py
collected 4 items                                                                  

test1.py ..                                                                        
test2.py ..

============================= 4 passed in 0.08 seconds =============================

importing variable in imported.py corresponds to the module that has imported the imported.py module.

And the problem is that the line import imported in test2.py doesn't cause test2 imported this file to appear in the logs. Why is that?