[Palette] allow addition

Closes #8

.travis.yml

@@ -1,4 +1,4 @@
-sudo: false
+sudo: false  # run on new infrastructure
 language: python
 python:
   # - "2.6"  # green doesn't run on Python 2.6
@@ -19,6 +19,6 @@ install:
   - pip install -r test/requirements.txt
   - pip install coveralls
 # command to run tests
-script: green -vvr
+script: green test -vvr
 after_success:
-  coveralls
+  - coveralls

colourettu/_colour.py

@@ -97,8 +97,8 @@ def __init__(self, mycolour="#FFF", normalized_rgb=False):
                         (type(mycolour[1]) in (float, int)) and
                         (type(mycolour[2]) in (float, int))):
                         if((0 <= mycolour[0] <= 1) and
-                            (0 <= mycolour[1] <= 1) and
-                            (0 <= mycolour[2] <= 1)):
+                           (0 <= mycolour[1] <= 1) and
+                           (0 <= mycolour[2] <= 1)):
                             self._r = int(mycolour[0]*255)
                             self._g = int(mycolour[1]*255)
                             self._b = int(mycolour[2]*255)

colourettu/_palette.py

@@ -78,6 +78,41 @@ def __str__(self):
     def __len__(self):
         return(len(self._colours))
 
+    def __add__(self, other):
+        """
+        - adding two `colourettu.palette`s will concatenate the two together
+        - if two `colourettu.palette`s are added, and the last colour of the
+        first palette is the same as the first colour of the second palette,
+        that colour will only appear once in the new palette
+        - `colourettu.palette`s and `colourettu.colour`s can be added to
+        create new `colourettu.palette`s
+        """
+        colour_for_type = colour()
+        palette_for_type = palette()
+        if type(other) is type(colour_for_type):
+            self._colours.append(other)
+            self._end = other
+            return self
+        elif type(other) is type(palette_for_type):
+            if (self._end == other._start):
+                self._colours.extend(other._colours[1:])
+            else:
+                self._colours.extend(other._colours)
+            self._end = other._end
+            return self
+        else:
+            raise TypeError('unsupported opperand type(s) for +: {} and {}'.format(type(self), type(other)))
+
+    def __radd__(self, other):
+        # used for `colour + palette`
+        colour_for_type = colour()
+        if type(other) is type(colour_for_type):
+            self._colours.insert(0, other)
+            self._start = other
+            return self
+        else:
+            raise TypeError('unsupported opperand type(s) for +: {} and {}'.format(type(self), type(other)))
+
     # TO-DO     def __init__(self)   #this allows :  for colour in palette:
 
     def from_list(self, list_of_colours, normalized_rgb=False):

docs/changelog.rst

@@ -1,6 +1,7 @@
 Changelog
 =========
 
+- :feature:'8' allow addition of palettes and palettes and colours
 - :support:`-` manage changelog with `Releases <https://github.com/bitprophet/releases>`_
 - :feature:`-` add `palette` class
 - :feature:`-` allow creation of colours from normalized rgb values

docs/requirements.rst

@@ -16,7 +16,7 @@ Testing *colourettu* requires:
 
 Then run (from the base directory)::
 
-	green tests
+	green test -vv
 
 
 Documentation Generation

test/test_colour.py

@@ -207,15 +207,14 @@ def test_eq(self):
         c5 = colourettu.colour('#123456')
         c6 = c5
         c7 = colourettu.colour('#000000')
-        c8 = colourettu.colour([0,0,0])
-        
+        c8 = colourettu.colour([0, 0, 0])
+
         self.assertEqual(c1, c2)
         self.assertEqual(c3, c4)
         self.assertEqual(c5, c6)
         self.assertEqual(c7, c8)
 
 
-
 class Test_Contrast(unittest.TestCase):
 
     def test_white_white(self):

test/test_palette.py

@@ -38,19 +38,19 @@ def test_from_list_tuple(self):
         self.assertEqual(p1._end, colourettu.colour('#aabcde'))
 
     def test_convert_start_colour(self):
-        p1 = colourettu.palette(start_colour = '#124')
+        p1 = colourettu.palette(start_colour='#124')
         self.assertEqual(p1._start, colourettu.colour('#112244'))
 
     def test_convert_end_colour(self):
-        p1 = colourettu.palette(end_colour = '#a7f')
+        p1 = colourettu.palette(end_colour='#a7f')
         self.assertEqual(p1._end, colourettu.colour('#aa77ff'))
 
     def test_invalid_start_colour(self):
         with self.assertRaises(ValueError):
             p1 = colourettu.palette(start_colour="more")
 
     def test_invalid_end_colour(self):
-       with self.assertRaises(ValueError):
+        with self.assertRaises(ValueError):
             p1 = colourettu.palette(end_colour=[1, 2, 3, 4])
 
     def test_from_list_convert_list_colour(self):
@@ -63,6 +63,39 @@ def test_from_list_convert_list_colour(self):
         self.assertEqual(p1._start, colourettu.colour('#c2e5ae'))
         self.assertEqual(p1._end, colourettu.colour('#9295c0'))
 
+    def test_palette_plus_colour(self):
+        p1 = colourettu.palette()
+        c2 = colourettu.colour('#123')
+        p2 = p1 + c2
+        self.assertEqual(len(p2), 3)
+        self.assertEqual(p2._start, colourettu.colour('#fff'))
+        self.assertEqual(p2._end, colourettu.colour('#112233'))
+
+    def test_colour_plus_palette(self):
+        p1 = colourettu.palette()
+        c2 = colourettu.colour('#abc')
+        p2 = c2 + p1
+        self.assertEqual(len(p2), 3)
+        self.assertEqual(p2._start, colourettu.colour('#aabbcc'))
+        self.assertEqual(p2._end, colourettu.colour('#000'))
+
+    def test_palette_plus_palette(self):
+        p1 = colourettu.palette()
+        p2 = colourettu.palette('#abc', '#345')
+        p3 = p1 + p2
+        self.assertEqual(len(p3), 4)
+        self.assertEqual(p3._start, colourettu.colour('#fff'))
+        self.assertEqual(p3._end, colourettu.colour('#345'))
+
+    def test_palette_plus_palette_overlapping_colour(self):
+        p1 = colourettu.palette('#123', '#456')
+        p2 = colourettu.palette('#456', '#789')
+        p3 = p1 + p2
+        self.assertEqual(len(p3), 3)
+        self.assertEqual(p3._start, colourettu.colour('#123'))
+        self.assertEqual(p3._end, colourettu.colour('#789'))
+        self.assertEqual(p3._colours[1], colourettu.colour('#456'))
+
 
 class Test_Palette_with_Images(unittest.TestCase):
 
@@ -77,6 +110,10 @@ def test_to_image(self):
         p1.to_image()
         self.assertTrue(os.path.isfile('palette.png'))
 
+    @skip('not yet defined')
+    def test_to_image_alpha_channel(self):
+        pass
+
     @skip('not yet defined')
     def test_to_image_band_width(self):
         pass