fix: verify work during continuously hidden guest intervals

tests/test_profiles.py

@@ -65,6 +65,16 @@ class ProfilesTests(unittest.TestCase):
                 with self.subTest(field=field, value=value), self.assertRaises(ValueError):
                     Profile('guest', self.iso, **{field: value})
 
+    def test_refresh_vertical_descriptor_boundaries(self):
+        for value in (0, 50000, 255000):
+            path = self.root / 'guest.toml'
+            save_profile(path, Profile('guest', refresh_millihz=value))
+            self.assertEqual(load_profile(path).refresh_millihz, value)
+            path.unlink()
+        for value in (1, 30000, 49999, 255001, 1000000):
+            with self.subTest(refresh=value), self.assertRaises(ValueError):
+                Profile('guest', refresh_millihz=value)
+
     def test_profile_name_must_match_filename(self):
         path = self.root / 'guest.toml'
         path.write_text(f'name = "other"\niso = "{self.iso}"\n')