Add limited support for named colors

Resolves #41

babi/color.py

@@ -1,5 +1,9 @@
 from typing import NamedTuple
 
+# TODO: find a standard which defines these
+# limited number of "named" colors
+NAMED_COLORS = {'white': '#ffffff', 'black': '#000000'}
+
 
 class Color(NamedTuple):
     r: int
@@ -8,4 +12,7 @@ class Color(NamedTuple):
 
     @classmethod
     def parse(cls, s: str) -> 'Color':
-        return cls(r=int(s[1:3], 16), g=int(s[3:5], 16), b=int(s[5:7], 16))
+        if s.startswith('#'):
+            return cls(r=int(s[1:3], 16), g=int(s[3:5], 16), b=int(s[5:7], 16))
+        else:
+            return cls.parse(NAMED_COLORS[s])

tests/color_test.py

@@ -0,0 +1,15 @@
+import pytest
+
+from babi.color import Color
+
+
+@pytest.mark.parametrize(
+    ('s', 'expected'),
+    (
+        ('#1e77d3', Color(0x1e, 0x77, 0xd3)),
+        ('white', Color(0xff, 0xff, 0xff)),
+        ('black', Color(0x00, 0x00, 0x00)),
+    ),
+)
+def test_color_parse(s, expected):
+    assert Color.parse(s) == expected