Implemented errors in constructor, added associated tests

midisnake/errors.py

@@ -0,0 +1,25 @@
+#                       MIT License
+# 
+# Copyright (c) 27/08/17 Ennis Massey
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+class LengthError(Exception):
+    """Raised when data is the wrong length"""
+    pass

midisnake/structure.py

@@ -23,6 +23,8 @@
 from io import BufferedReader
 from abc import ABCMeta, abstractmethod
 
+from midisnake.errors import LengthError
+
 __all__ = ["Header", "Event"]
 
 
@@ -63,15 +65,23 @@ class Event(metaclass=ABCMeta):  # pramga: no
 
     def __init__(self, data: int) -> None:
         self.raw_data = data
-        self._process(data)
+        if len(hex(data)[2:]) != 6:
+            err_msg = "Length of given data is incorrect. The length is {} and it should be 6".format(
+                len(hex(data)[2:]))
+            raise LengthError(err_msg)
+        if self.valid(data):
+            self._process(data)
+        else:
+            err_msg = "{} given invalid data".format(type(self).__name__)
+            raise ValueError(err_msg)
+
 
     def __repr__(self) -> str:
         return "<MIDIEvent: {}>".format(self.event_name)
 
     def __str__(self) -> str:
         return "MIDIEvent: {}".format(self.event_name)
 
-
     @classmethod
     def valid(cls, data: int) -> bool:
         """
@@ -111,7 +121,6 @@ class Track:
     events = None  # type: List[Event]
 
 
-
 class VariableLengthValue:
     """Parses and stores a MIDI variable length value
     

tests/test_events.py

@@ -18,4 +18,46 @@
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-# SOFTWARE.
+# SOFTWARE.
+from unittest import TestCase
+from unittest.mock import MagicMock, call
+
+from midisnake.events import NoteOff, NoteOn, PolyphonicAftertouch, PitchBend
+from midisnake.errors import LengthError
+
+
+class TestNoteOn(TestCase):
+    def test_validate(self):
+        test_val = NoteOn.valid(0x900000)
+        self.assertTrue(test_val, "Generic MIDI NoteOn message failed validation. Value was 0x{:X}".format(test_val))
+        test_val = NoteOn.valid(0x800000)
+        self.assertFalse(test_val,
+                         "Generic MIDI NoteOn message shouldn't have validated, but did. Value was 0x{:x}".format(
+                             test_val)
+                         )
+
+    def test_constructor(self):
+        # Test constructor of generic version
+        test_val = NoteOn(0x900000)
+        match_val = {
+            'channel_number': 0,
+            'note_name': 'C',
+            'note_number': 0,
+            'note_velocity': 0,
+            'raw_data': 9437184
+        }
+        self.assertEqual(vars(test_val),
+                         match_val, "MIDI NoteOn constructed from value 0x{:X} is incorrect".format(0x900000)
+                         )
+        # Test Length Exceptions
+        with self.assertRaises(LengthError,
+                               msg="NoteOn did not raise LengthError when given value 0x123001929391923919"
+                               ) as exc:
+            NoteOn(0x123001929391923919)
+
+        with self.assertRaises(LengthError,
+                               msg="NoteOn did not raise LengthError when given value 0x1"
+                               ) as exc:
+            NoteOn(0x1)
+
+