Add a unit test for polygon intersection

Contributes to #35

UM/Math/Polygon.py

@@ -51,9 +51,9 @@ def intersectsPolygon(self, other):
             aMin, aMax = self.project(normal)
             bMin, bMax = other.project(normal)
             if aMin > bMax:
-                return False
+                return None
             if bMin > aMax:
-                return False
+                return None
             size = min(aMax, bMax) - max(aMin, bMin)
             if size < retSize:
                 ret = normal * (size + 0.1)
@@ -70,9 +70,9 @@ def intersectsPolygon(self, other):
             aMin, aMax = self.project(normal)
             bMin, bMax = other.project(normal)
             if aMin > bMax:
-                return False
+                return None
             if bMin > aMax:
-                return False
+                return None
             size = min(aMax, bMax) - max(aMin, bMin)
             if size < retSize:
                 ret = normal * -(size + 0.1)

tests/Math/TestPolygon.py

@@ -0,0 +1,110 @@
+# Copyright (c) 2015 Ultimaker B.V.
+# Uranium is released under the terms of the AGPLv3 or higher.
+
+from UM.Math.Polygon import Polygon
+from UM.Math.Float import Float
+
+import numpy
+import math
+import unittest
+
+class TestPolygon(unittest.TestCase):
+    def setUp(self):
+        # Called before the first testfunction is executed
+        pass
+
+    def tearDown(self):
+        # Called after the last testfunction was executed
+        pass
+
+    def test_project(self):
+        p = Polygon(numpy.array([
+            [0.0, 1.0],
+            [1.0, 1.0],
+            [1.0, 2.0],
+            [0.0, 2.0]
+        ], numpy.float32))
+
+        normal = numpy.array([0.0, 1.0])
+        self.assertEqual((1.0, 2.0), p.project(normal))
+
+        normal = numpy.array([1.0, 0.0])
+        self.assertEqual((0.0, 1.0), p.project(normal))
+
+        normal = numpy.array([math.sqrt(0.5), math.sqrt(0.5)])
+        result = p.project(normal)
+        self.assertTrue(Float.fuzzyCompare(result[0], 0.70710678), "{0} does not equal {1}".format(result[0], 0.70710678))
+        self.assertTrue(Float.fuzzyCompare(result[1], 2.12132034), "{0} does not equal {1}".format(result[1], 2.12132034))
+
+    def test_intersectsPolygon(self):
+        p1 = Polygon(numpy.array([
+            [0.0, 0.0],
+            [1.0, 0.0],
+            [1.0, 1.0],
+            [0.0, 1.0]
+        ], numpy.float32))
+
+        p2 = Polygon(numpy.array([
+            [0.5, 0.5],
+            [1.5, 0.5],
+            [1.5, 1.5],
+            [0.5, 1.5]
+        ], numpy.float32))
+        result = p1.intersectsPolygon(p2)
+        print(result)
+
+        p2 = Polygon(numpy.array([
+            [2.5, 2.5],
+            [3.5, 2.5],
+            [3.5, 3.5],
+            [2.5, 3.5]
+        ], numpy.float32))
+        result = p1.intersectsPolygon(p2)
+        print(result)
+
+        p1 = Polygon(numpy.array([
+            [0, 0],
+            [10, 0],
+            [10, 10],
+            [0, 10]
+        ], numpy.float32))
+
+        p2 = Polygon(numpy.array([
+            [5, 5],
+            [15, 5],
+            [15, 15],
+            [5, 15]
+        ], numpy.float32))
+        result = p1.intersectsPolygon(p2)
+        print(result)
+
+        p2 = Polygon(numpy.array([
+            [5, 5],
+            [5, 15],
+            [-10, 15],
+            [-10, 5]
+        ], numpy.float32))
+        result = p1.intersectsPolygon(p2)
+        print(result)
+
+        p2 = Polygon(numpy.array([
+            [2.5, 7.5],
+            [7.5, 7.5],
+            [7.5, 15.0],
+            [2.5, 15.0]
+        ]))
+        result = p1.intersectsPolygon(p2)
+        print(result)
+
+        p2 = Polygon(numpy.array([
+            [2.5, 7.5],
+            [-2.5, 7.5],
+            [-2.5, -5.0],
+            [2.5, -5.0]
+        ]))
+        result = p1.intersectsPolygon(p2)
+        print(result)
+
+
+if __name__ == "__main__":
+    unittest.main()