# HG changeset patch
# User Branko Majic <branko@majic.rs>
# Date 2013-11-09 13:59:22
# Node ID a9320f18b39960426f00e1e7cd007dac0def56e5
# Parent  353630bdfef62e5617d5bf0550294001fb0ad5ed

Noticket: Add more logic to the distinct colour generation. Add some extra tests for this.

diff --git a/conntrackt/tests/test_utils.py b/conntrackt/tests/test_utils.py
--- a/conntrackt/tests/test_utils.py
+++ b/conntrackt/tests/test_utils.py
@@ -139,6 +139,23 @@ class GetDistinctColorsTest(TestCase):
         equal = abs(colors[0].hsl["h"] + 1 - colors[12].hsl["h"] - reference) < delta
         self.assertEqual(True, equal)
 
+    def test_zero_count(self):
+        """
+        Tests if an empty list is returned in case the requested count is 0.
+        """
+
+        colors = utils.get_distinct_colors(0)
+
+        self.assertIsInstance(colors, list)
+        self.assertEqual(len(colors), 0)
+
+    def test_negative_count(self):
+        """
+        Tests if proper exception is raised in case a negative count is passed.
+        """
+
+        self.assertRaisesRegexp(ValueError, "^Count must be a non-negative integer value\.$", utils.get_distinct_colors, -10)
+
 
 class GenerateProjectDiagramTest(TestCase):
     """
diff --git a/conntrackt/utils.py b/conntrackt/utils.py
--- a/conntrackt/utils.py
+++ b/conntrackt/utils.py
@@ -104,6 +104,12 @@ def get_distinct_colors(count, start=pal
         List of distinct palette.Color instances.
     """
 
+    # If zero is passed as count, return empty list.
+    if count == 0:
+        return []
+    elif count < 0:
+        raise ValueError("Count must be a non-negative integer value.")
+
     # Read the HSL from provided Color.
     hue, sat, lum = start.hsl["h"], start.hsl["s"], start.hsl["l"]