Address PR comments

Author: Theofilos Manitaras

reframe/utility/os_ext.py

@@ -229,7 +229,7 @@ def inpath(entry, pathvar):
 
 def is_interactive():
     '''Returns whether the given Python session is interactive'''
-    return bool(getattr(sys, 'ps1', sys.flags.interactive))
+    return hasattr(sys, 'ps1') or sys.flags.interactive
 
 
 def subdirs(dirname, recurse=False):

unittests/test_utility.py

@@ -173,10 +173,16 @@ def test_samefile(self):
                                os.path.join(prefix, 'broken1'))
         shutil.rmtree(prefix)
 
+    # FIXME: This should be changed in order to use the `monkeypatch`
+    # fixture of `pytest` instead of creating an instance of `MonkeyPatch`
     def test_is_interactive(self):
-        # Set `sys.ps1` to immitate an interactive session
-        sys.ps1 = 'rfm>>> '
-        assert os_ext.is_interactive()
+        from _pytest.monkeypatch import MonkeyPatch  # noqa: F401, F403
+
+        monkey = MonkeyPatch()
+        with monkey.context() as c:
+            # Set `sys.ps1` to immitate an interactive session
+            c.setattr(sys, 'ps1', 'rfm>>> ', raising=False)
+            assert os_ext.is_interactive()
 
     def test_is_url(self):
         repo_https = 'https://github.com/eth-cscs/reframe.git'