Fix terminal model mapping

pycoax/coax/protocol.py

@@ -76,15 +76,30 @@ class KeystrokePollResponse(PollResponse):
 class TerminalId:
     """Terminal model and keyboard."""
 
+    _MODEL_MAP = {
+        0b010: 2,
+        0b011: 3,
+        0b111: 4,
+        0b110: 5
+    }
+
     def __init__(self, value):
         if (value & 0x1) != 0:
             raise ValueError('Invalid terminal identifier')
 
         self.value = value
 
-        self.model = (value & 0x0e) >> 1
+        model = (value & 0x0e) >> 1
+
+        if model not in TerminalId._MODEL_MAP:
+            raise ValueError('Invalid model')
+
+        self.model = TerminalId._MODEL_MAP[model]
         self.keyboard = (value & 0xf0) >> 4
 
+    def __repr__(self):
+        return f'<TerminalId model={self.model}, keyboard={self.keyboard}>'
+
 def poll(interface, **kwargs):
     """Execute a POLL command."""
     response = _execute_read_command(interface, Command.POLL, allow_trta_response=True,

pycoax/tests/test_protocol.py

@@ -4,7 +4,7 @@ from unittest.mock import Mock
 import context
 
 from coax import PollResponse, KeystrokePollResponse, ProtocolError
-from coax.protocol import Command, _execute_read_command, _execute_write_command, _pack_command_word, _unpack_data_words, _unpack_data_word
+from coax.protocol import Command, TerminalId, _execute_read_command, _execute_write_command, _pack_command_word, _unpack_data_words, _unpack_data_word
 
 class PollResponseTestCase(unittest.TestCase):
     def test_is_power_on_reset_complete(self):
@@ -25,6 +25,35 @@ class KeystrokePollResponseTestCase(unittest.TestCase):
         with self.assertRaisesRegex(ValueError, 'Invalid keystroke poll response'):
             response = KeystrokePollResponse(0b0000001000)
 
+class TerminalIdTestCase(unittest.TestCase):
+    def test_model_2(self):
+        terminal_id = TerminalId(0b00000100)
+
+        self.assertEqual(terminal_id.model, 2)
+
+    def test_model_3(self):
+        terminal_id = TerminalId(0b00000110)
+
+        self.assertEqual(terminal_id.model, 3)
+
+    def test_model_4(self):
+        terminal_id = TerminalId(0b00001110)
+
+        self.assertEqual(terminal_id.model, 4)
+
+    def test_model_5(self):
+        terminal_id = TerminalId(0b00001100)
+
+        self.assertEqual(terminal_id.model, 5)
+
+    def test_invalid_identifier(self):
+        with self.assertRaisesRegex(ValueError, 'Invalid terminal identifier'):
+            terminal_id = TerminalId(0b00000001)
+
+    def test_invalid_model(self):
+        with self.assertRaisesRegex(ValueError, 'Invalid model'):
+            terminal_id = TerminalId(0b00000000)
+
 class ExecuteReadCommandTestCase(unittest.TestCase):
     def setUp(self):
         self.interface = Mock()