cat: fix Supported Radio Access Technologies state flag

TS 102 223 8.105 codes each supported technology in two bytes:
- the technology from 8.61
- state byte, b1 0 disabled/1 enabled
- b2-b8 RFU

Currently declared as FlagsEnum(Int8ub, enabled=0). kw value is used as
bitmask, so currently:

build {'enabled': True}      -> b4 02 08 00     disabled
build {'enabled': False}     -> b4 02 08 00     disabled
but parsed 08 00 / 08 01 / 08 ff  -> all {'enabled': True}

Use the bit the spec names + tests because well this is so easy that we
don't need tests is apparently not the right approach here..

Change-Id: I4dd16182eb06c99265aabab5d889967b890f6bf2

pySim/cat.py

@@ -729,8 +729,12 @@ class DnsServerAddress(COMPR_TLV_IE, tag=0xC0):
 
 # TS 102 223 Section 8.105
 class SupportedRadioAccessTechnologies(COMPR_TLV_IE, tag=0xB4):
+    # 2 bytes/entry:
+    # - technology of 8.61
+    # - state byte b1 is 0 disabled/1 enabled
+    # - b2-b8 RFU.
     AccessTechTuple = Struct('technology'/AccessTechnology.SingleAccessTech,
-                             'state'/FlagsEnum(Int8ub, enabled=0))
+                             'state'/FlagsEnum(Int8ub, enabled=1))
     _construct = GreedyRange(AccessTechTuple)
 
 # TS 102 223 Section 8.107

tests/unittests/test_cat.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""Tests for the CAT (Card Application Toolkit) COMPREHENSION-TLV data objects"""
+
+# (C) 2026 by sysmocom - s.f.m.c. GmbH
+# All Rights Reserved
+#
+# Author: Eric Wild <ewild@sysmocom.de>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# IEs not properly coverd by test_tlvs.py
+
+
+import unittest
+
+from osmocom.utils import b2h, h2b
+
+from pySim.cat import SupportedRadioAccessTechnologies
+
+
+class SupportedRadioAccessTechnologies_Test(unittest.TestCase):
+    """TS 102 223 8.105"""
+
+    def test_encode_technology_enabled(self):
+        """The flag used to have a bitmask of 0 so enabled -> 00 (that is disabled..)"""
+        ie = SupportedRadioAccessTechnologies(
+            decoded=[{'technology': 'eutran', 'state': {'enabled': True}}])
+        self.assertEqual(b2h(ie.to_tlv()), 'b4020801')
+
+    def test_encode_technology_disabled(self):
+        ie = SupportedRadioAccessTechnologies(
+            decoded=[{'technology': 'eutran', 'state': {'enabled': False}}])
+        self.assertEqual(b2h(ie.to_tlv()), 'b4020800')
+
+    def test_decode_technology(self):
+        """old 0 bitmask = all enabled, no way to disable"""
+        for encoded, enabled in [('b4020800', False), ('b4020801', True)]:
+            with self.subTest(encoded=encoded):
+                ie = SupportedRadioAccessTechnologies()
+                ie.from_tlv(h2b(encoded))
+                self.assertEqual(ie.decoded[0]['technology'], 'eutran')
+                self.assertEqual(ie.decoded[0]['state']['enabled'], enabled)
+
+    def test_decode_technology_multiple(self):
+        ie = SupportedRadioAccessTechnologies()
+        ie.from_tlv(h2b('b40408010000'))
+        self.assertEqual([(e['technology'], e['state']['enabled']) for e in ie.decoded],
+                         [('eutran', True), ('gsm', False)])
+
+
+
+if __name__ == "__main__":
+    unittest.main()