Merge pull request #20 from yuma-m/feature/chord-eq

Fix __eq__ of Chord and support __eq__ for Quality

README.md

@@ -46,6 +46,19 @@ on=None
 ['A', 'C', 'E', 'G']
 ```
 
+### Compare Chords
+
+```python
+>>> Chord("C") == Chord("D")
+False
+>>> Chord("C#") == Chord("Db")
+True
+>>> c = Chord("C")
+>>> c.transpose(2)
+>>> c == Chord("D")
+True
+```
+
 ### Find Chords
 
 ```python

pychord/chord.py

@@ -2,7 +2,7 @@
 
 
 from .parser import parse
-from .utils import transpose_note, display_appended, display_on
+from .utils import transpose_note, display_appended, display_on, note_to_val
 
 
 class Chord(object):
@@ -33,7 +33,16 @@ def __repr__(self):
         return "<Chord: {}>".format(self._chord)
 
     def __eq__(self, other):
-        return self._chord == other.chord
+        if note_to_val(self._root) != note_to_val(other.root):
+            return False
+        if self._quality != other.quality:
+            return False
+        if self._appended != other.appended:
+            return False
+        if self._on and other.on:
+            if note_to_val(self._on) != note_to_val(other.on):
+                return False
+        return True
 
     def __ne__(self, other):
         return not self.__eq__(other)

pychord/quality.py

@@ -25,6 +25,12 @@ def __unicode__(self):
     def __str__(self):
         return self._quality
 
+    def __eq__(self, other):
+        return self._quality == other.quality
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
     @property
     def quality(self):
         """ Get name of quality """
@@ -59,8 +65,8 @@ def append_on_chord(self, on_chord, root):
         root_val = note_to_val(root)
         on_chord_val = note_to_val(on_chord) - root_val
 
-        lista = list(self.components)
-        for idx, val in enumerate(lista):
+        list_ = list(self.components)
+        for idx, val in enumerate(list_):
             if val % 12 == on_chord_val:
                 self.components.remove(val)
                 break

test/test_transpose.py

@@ -13,41 +13,44 @@ def test_transpose_zero(self):
         c.transpose(0)
         self.assertEqual(c.root, "A")
         self.assertEqual(c.quality.quality, "m")
+        self.assertEqual(c, Chord("Am"))
 
     def test_transpose_positive(self):
         c = Chord("Am")
         c.transpose(3)
         self.assertEqual(c.root, "C")
         self.assertEqual(c.quality.quality, "m")
+        self.assertEqual(c, Chord("Cm"))
 
     def test_transpose_negative(self):
         c = Chord("Am")
         c.transpose(-4)
         self.assertEqual(c.root, "F")
         self.assertEqual(c.quality.quality, "m")
+        self.assertEqual(c, Chord("Fm"))
 
     def test_transpose_slash(self):
         c = Chord("Am7/G")
         c.transpose(3)
         self.assertEqual(c.root, "C")
         self.assertEqual(c.quality.quality, "m7")
         self.assertEqual(c.on, "Bb")
+        self.assertEqual(c, Chord("Cm7/Bb"))
 
     def test_invalid_transpose_type(self):
         c = Chord("Am")
         self.assertRaises(TypeError, c.transpose, "A")
 
     def test_transpose_eq1(self):
-        c1 = Chord("C")
-        c1.transpose(1)
-        c2 = Chord("Db")
-        self.assertEqual(c1, c2)
+        c = Chord("C")
+        c.transpose(1)
+        self.assertEqual(c, Chord("C#"))
+        self.assertEqual(c, Chord("Db"))
 
     def test_transpose_eq2(self):
-        c1 = Chord("C")
-        c1.transpose(2)
-        c2 = Chord("D")
-        self.assertEqual(c1, c2)
+        c = Chord("C")
+        c.transpose(2)
+        self.assertEqual(c, Chord("D"))
 
 
 if __name__ == '__main__':