--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test_centroid.py	Sun Dec 17 13:35:45 2017 -0800
@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+
+"""
+test centroid calculations
+"""
+
+import common
+import os
+import unittest
+from tvii import centroid
+
+
+class CentroidTest(unittest.TestCase):
+
+    def test_square(self):
+        """find the centroids of these boring squares"""
+
+        # a boring square centered about the origin
+        points = [(5., 0.),
+                  (0., 5.),
+                  (-5., 0.),
+                  (0., -5)]
+        center = centroid.centroid(*points)
+
+        tolerance = 1e-6
+        assert len(center) == 2  # dimensions
+        assert all([abs(dim) < tolerance
+                    for dim in center])
+
+    def test_main(self):
+        """smoketest for console-script entry point"""
+
+        datafile = common.datafile('circles.csv')
+        assert os.path.exists(datafile)
+        centroid.main([datafile])
+
+if __name__ == '__main__':
+    unittest.main()