diff --git a/tests/test_files.py b/tests/test_files.py
new file mode 100755
index 0000000..3fb1062
--- /dev/null
+++ b/tests/test_files.py
@@ -0,0 +1,262 @@
+#!/usr/bin/env python3
+
+# (C) 2023 by Harald Welte <laforge@osmocom.org>
+#
+# 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/>.
+
+import unittest
+import logging
+
+from pySim.utils import *
+from pySim.filesystem import *
+
+import pySim.iso7816_4
+import pySim.ts_102_221
+import pySim.ts_102_222
+import pySim.ts_31_102
+import pySim.ts_31_103
+import pySim.ts_51_011
+import pySim.sysmocom_sja2
+import pySim.gsm_r
+
+def get_qualified_name(c):
+    """return the qualified (by module) name of a class."""
+    return "%s.%s" % (c.__module__, c.__name__)
+
+class LinFixed_Test(unittest.TestCase):
+    classes = all_subclasses(LinFixedEF)
+
+    def test_decode_record(self):
+        """Test the decoder for a linear-fixed EF.  Requires the given LinFixedEF subclass
+        to have an '_test_decode' attribute, containing a list of tuples. Each tuple can
+        either be a
+            * 2-tuple (hexstring, decoded_dict) or a
+            * 3-tuple (hexstring, record_nr, decoded_dict)
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_decode'):
+                for t in c._test_decode:
+                    with self.subTest(name, test_decode=t):
+                        inst = c()
+                        if len(t) == 2:
+                            encoded = t[0]
+                            rec_num = 1
+                            decoded = t[1]
+                        else:
+                            encoded = t[0]
+                            rec_num = t[1]
+                            decoded = t[2]
+                        logging.debug("Testing decode of %s", name)
+                        re_dec = inst.decode_record_hex(encoded, rec_num)
+                        self.assertEqual(decoded, re_dec)
+
+    def test_encode_record(self):
+        """Test the encoder for a linear-fixed EF.  Requires the given LinFixedEF subclass
+        to have an '_test_encode' attribute, containing a list of tuples. Each tuple can
+        either be a
+            * 2-tuple (hexstring, decoded_dict) or a
+            * 3-tuple (hexstring, record_nr, decoded_dict)
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_encode'):
+                for t in c._test_encode:
+                    with self.subTest(name, test_encode=t):
+                        inst = c()
+                        if len(t) == 2:
+                            encoded = t[0]
+                            rec_num = 1
+                            decoded = t[1]
+                        else:
+                            encoded = t[0]
+                            rec_num = t[1]
+                            decoded = t[2]
+                        logging.debug("Testing encode of %s", name)
+                        re_enc = inst.encode_record_hex(decoded, rec_num)
+                        self.assertEqual(encoded, re_enc)
+
+    def test_de_encode_record(self):
+        """Test the decoder and encoder for a linear-fixed EF.  Performs first a decoder
+        test, and then re-encodes the decoded data, comparing the re-encoded data with the
+        initial input data.
+
+        Requires the given LinFixedEF subclass to have a '_test_de_encode' attribute,
+        containing a list of tuples. Each tuple can
+        either be a
+            * 2-tuple (hexstring, decoded_dict) or a
+            * 3-tuple (hexstring, record_nr, decoded_dict)
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_de_encode'):
+                for t in c._test_de_encode:
+                    with self.subTest(name, test_de_encode=t):
+                        inst = c()
+                        if len(t) == 2:
+                            encoded = t[0]
+                            rec_num = 1
+                            decoded = t[1]
+                        else:
+                            encoded = t[0]
+                            rec_num = t[1]
+                            decoded = t[2]
+                        logging.debug("Testing decode of %s", name)
+                        re_dec = inst.decode_record_hex(encoded, rec_num)
+                        self.assertEqual(decoded, re_dec)
+                        # re-encode the decoded data
+                        logging.debug("Testing re-encode of %s", name)
+                        re_enc = inst.encode_record_hex(re_dec, rec_num)
+                        self.assertEqual(encoded, re_enc)
+
+
+class TransRecEF_Test(unittest.TestCase):
+    classes = all_subclasses(TransRecEF)
+
+    def test_decode_record(self):
+        """Test the decoder for a transparent record-oriented EF.  Requires the given TransRecEF subclass
+        to have an '_test_decode' attribute, containing a list of tuples. Each tuple has to be a
+        2-tuple (hexstring, decoded_dict).
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_decode'):
+                for t in c._test_decode:
+                    with self.subTest(name, test_decode=t):
+                        inst = c()
+                        encoded = t[0]
+                        decoded = t[1]
+                        logging.debug("Testing decode of %s", name)
+                        re_dec = inst.decode_record_hex(encoded)
+                        self.assertEqual(decoded, re_dec)
+
+    def test_encode_record(self):
+        """Test the encoder for a transparent record-oriented EF.  Requires the given TransRecEF subclass
+        to have an '_test_encode' attribute, containing a list of tuples. Each tuple has to be a
+        2-tuple (hexstring, decoded_dict).
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_decode'):
+                for t in c._test_decode:
+                    with self.subTest(name, test_decode=t):
+                        inst = c()
+                        encoded = t[0]
+                        decoded = t[1]
+                        logging.debug("Testing decode of %s", name)
+                        re_dec = inst.decode_record_hex(encoded)
+                        self.assertEqual(decoded, re_dec)
+
+
+    def test_de_encode_record(self):
+        """Test the decoder and encoder for a transparent record-oriented EF.  Performs first a decoder
+        test, and then re-encodes the decoded data, comparing the re-encoded data with the
+        initial input data.
+
+        Requires the given TransRecEF subclass to have a '_test_de_encode' attribute,
+        containing a list of tuples. Each tuple has to be a 2-tuple (hexstring, decoded_dict).
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_de_encode'):
+                for t in c._test_de_encode:
+                    with self.subTest(name, test_de_encode=t):
+                        inst = c()
+                        encoded = t[0]
+                        decoded = t[1]
+                        logging.debug("Testing decode of %s", name)
+                        re_dec = inst.decode_record_hex(encoded)
+                        self.assertEqual(decoded, re_dec)
+                        # re-encode the decoded data
+                        logging.debug("Testing re-encode of %s", name)
+                        re_enc = inst.encode_record_hex(re_dec)
+                        self.assertEqual(encoded, re_enc)
+
+
+class TransparentEF_Test(unittest.TestCase):
+    @classmethod
+    def get_classes(cls):
+        """get list of TransparentEF sub-classes which are not a TransRecEF subclass."""
+        classes = all_subclasses(TransparentEF)
+        trans_rec_classes = all_subclasses(TransRecEF)
+        return filter(lambda c: c not in trans_rec_classes, classes)
+
+    @classmethod
+    def setUpClass(cls):
+        """set-up method called once for this class by unittest framework"""
+        cls.classes = cls.get_classes()
+
+    def test_decode_file(self):
+        """Test the decoder for a transparent EF.  Requires the given TransparentEF subclass
+        to have a '_test_decode' attribute, containing a list of tuples. Each tuple
+        is a 2-tuple (hexstring, decoded_dict).
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_decode'):
+                for t in c._test_decode:
+                    with self.subTest(name, test_decode=t):
+                        inst = c()
+                        encoded = t[0]
+                        decoded = t[1]
+                        logging.debug("Testing decode of %s", name)
+                        re_dec = inst.decode_hex(encoded)
+                        self.assertEqual(decoded, re_dec)
+
+    def test_encode_file(self):
+        """Test the encoder for a transparent EF.  Requires the given TransparentEF subclass
+        to have a '_test_encode' attribute, containing a list of tuples. Each tuple
+        is a 2-tuple (hexstring, decoded_dict).
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_encode'):
+                for t in c._test_encode:
+                    with self.subTest(name, test_encode=t):
+                        inst = c()
+                        encoded = t[0]
+                        decoded = t[1]
+                        logging.debug("Testing encode of %s", name)
+                        re_dec = inst.decode_hex(encoded)
+                        self.assertEqual(decoded, re_dec)
+
+    def test_de_encode_file(self):
+        """Test the decoder and encoder for a transparent EF.  Performs first a decoder
+        test, and then re-encodes the decoded data, comparing the re-encoded data with the
+        initial input data.
+
+        Requires the given TransparentEF subclass to have a '_test_de_encode' attribute,
+        containing a list of tuples. Each tuple is a 2-tuple (hexstring, decoded_dict).
+        """
+        for c in self.classes:
+            name = get_qualified_name(c)
+            if hasattr(c, '_test_de_encode'):
+                for t in c._test_de_encode:
+                    with self.subTest(name, test_de_encode=t):
+                        inst = c()
+                        encoded = t[0]
+                        decoded = t[1]
+                        logging.debug("Testing decode of %s", name)
+                        re_dec = inst.decode_hex(encoded)
+                        self.assertEqual(decoded, re_dec)
+                        logging.debug("Testing re-encode of %s", name)
+                        re_dec = inst.decode_hex(encoded)
+                        re_enc = inst.encode_hex(re_dec)
+                        self.assertEqual(encoded, re_enc)
+
+
+if __name__ == '__main__':
+    logger = logging.getLogger()
+    logger.setLevel(logging.DEBUG)
+    unittest.main()