Copy back a lot of the 2014 code.

Change-Id: I552292d8bd7bce4409e02d254bef06a9cc009568
diff --git a/y2014/control_loops/python/polydrivetrain_test.py b/y2014/control_loops/python/polydrivetrain_test.py
new file mode 100755
index 0000000..434cdca
--- /dev/null
+++ b/y2014/control_loops/python/polydrivetrain_test.py
@@ -0,0 +1,82 @@
+#!/usr/bin/python
+
+import polydrivetrain
+import numpy
+from numpy.testing import *
+import polytope
+import unittest
+
+__author__ = 'Austin Schuh (austin.linux@gmail.com)'
+
+
+class TestVelocityDrivetrain(unittest.TestCase):
+  def MakeBox(self, x1_min, x1_max, x2_min, x2_max):
+    H = numpy.matrix([[1, 0],
+                      [-1, 0],
+                      [0, 1],
+                      [0, -1]])
+    K = numpy.matrix([[x1_max],
+                      [-x1_min],
+                      [x2_max],
+                      [-x2_min]])
+    return polytope.HPolytope(H, K)
+
+  def test_coerce_inside(self):
+    """Tests coercion when the point is inside the box."""
+    box = self.MakeBox(1, 2, 1, 2)
+
+    # x1 = x2
+    K = numpy.matrix([[1, -1]])
+    w = 0
+
+    assert_array_equal(polydrivetrain.CoerceGoal(box, K, w,
+                                                 numpy.matrix([[1.5], [1.5]])),
+                       numpy.matrix([[1.5], [1.5]]))
+
+  def test_coerce_outside_intersect(self):
+    """Tests coercion when the line intersects the box."""
+    box = self.MakeBox(1, 2, 1, 2)
+
+    # x1 = x2
+    K = numpy.matrix([[1, -1]])
+    w = 0
+
+    assert_array_equal(polydrivetrain.CoerceGoal(box, K, w, numpy.matrix([[5], [5]])),
+                       numpy.matrix([[2.0], [2.0]]))
+
+  def test_coerce_outside_no_intersect(self):
+    """Tests coercion when the line does not intersect the box."""
+    box = self.MakeBox(3, 4, 1, 2)
+
+    # x1 = x2
+    K = numpy.matrix([[1, -1]])
+    w = 0
+
+    assert_array_equal(polydrivetrain.CoerceGoal(box, K, w, numpy.matrix([[5], [5]])),
+                       numpy.matrix([[3.0], [2.0]]))
+
+  def test_coerce_middle_of_edge(self):
+    """Tests coercion when the line intersects the middle of an edge."""
+    box = self.MakeBox(0, 4, 1, 2)
+
+    # x1 = x2
+    K = numpy.matrix([[-1, 1]])
+    w = 0
+
+    assert_array_equal(polydrivetrain.CoerceGoal(box, K, w, numpy.matrix([[5], [5]])),
+                       numpy.matrix([[2.0], [2.0]]))
+
+  def test_coerce_perpendicular_line(self):
+    """Tests coercion when the line does not intersect and is in quadrant 2."""
+    box = self.MakeBox(1, 2, 1, 2)
+
+    # x1 = -x2
+    K = numpy.matrix([[1, 1]])
+    w = 0
+
+    assert_array_equal(polydrivetrain.CoerceGoal(box, K, w, numpy.matrix([[5], [5]])),
+                       numpy.matrix([[1.0], [1.0]]))
+
+
+if __name__ == '__main__':
+  unittest.main()