issue #17: frame: Add unit test for SABME decode

tests/test_frame/test_uframe.py

@@ -3,7 +3,8 @@
 from aioax25.frame import AX25Frame, \
         AX25UnnumberedInformationFrame, AX25FrameRejectFrame, \
         AX25UnnumberedFrame, AX25DisconnectModeFrame, \
-        AX25SetAsyncBalancedModeFrame, AX25TestFrame
+        AX25SetAsyncBalancedModeFrame, \
+        AX25SetAsyncBalancedModeExtendedFrame, AX25TestFrame
 
 from ..nosecompat import eq_
 from ..hex import from_hex, hex_cmp
@@ -57,6 +58,37 @@ def test_decode_sabm_payload():
     except ValueError as e:
         eq_(str(e), 'Frame does not support payload')
 
+def test_decode_sabme():
+    """
+    Test that a SABME frame is recognised and decoded.
+    """
+    frame = AX25Frame.decode(
+            from_hex(
+                'ac 96 68 84 ae 92 e0'      # Destination
+                'ac 96 68 9a a6 98 61'      # Source
+                '6f'                        # Control byte
+            )
+    )
+    assert isinstance(frame, AX25SetAsyncBalancedModeExtendedFrame), \
+            'Did not decode to SABME frame'
+
+def test_decode_sabme_payload():
+    """
+    Test that a SABME frame forbids payload.
+    """
+    try:
+        AX25Frame.decode(
+                from_hex(
+                    'ac 96 68 84 ae 92 e0'      # Destination
+                    'ac 96 68 9a a6 98 61'      # Source
+                    '6f'                        # Control byte
+                    '11 22 33 44 55'            # Payload
+                )
+        )
+        assert False, 'This should not have worked'
+    except ValueError as e:
+        eq_(str(e), 'Frame does not support payload')
+
 def test_decode_uframe_payload():
     """
     Test that U-frames other than FRMR and UI are forbidden to have payloads.