Add color test.

test/test_color.py

@@ -0,0 +1,17 @@
+from colour import Color
+
+from roentgen.color import is_bright
+
+__author__: str = "Sergey Vartanov"
+__email__: str = "me@enzet.ru"
+
+
+def test_is_bright():
+    """
+    Test detecting color brightness.
+    """
+    assert is_bright(Color("white"))
+    assert is_bright(Color("yellow"))
+    assert not is_bright(Color("brown"))
+    assert not is_bright(Color("black"))
+