add test for helical extrusion

tests/tests.py

@@ -0,0 +1,28 @@
+import unittest
+
+from freecad import app
+from freecad import part
+from freecad.gears.basegear import helicalextrusion
+
+
+
+class GearTests(unittest.TestCase):
+    def test_helical_extrusion(self):
+        """check if helical extrusion is working correctly"""
+        n = app.Vector(0, 0, 1)
+        m = app.Vector(0, 0, 0)
+        r = 10
+        h = 10
+        degree = 3.1415926535 / 4
+
+        a = part.Circle(m, n, r)
+        face = part.Face(part.Wire(a.toShape()))
+        s = helicalextrusion(face, h, 1)
+        
+        # face 0 is the cylinder
+        # face 1 is pointing in positive z direction
+        # face 2 is pointing in negative z direction
+        self.asserTrue((s.Faces[1].normalAt(0,0) - n).Length < 10e-15)
+        self.asserTrue((s.Faces[2].normalAt(0,0) + n).Length < 10e-15)
+        self.asserTrue(s.Faces[1].valueAt(0,0)[2] - h < 10e-15)
+        self.asserTrue(s.Faces[2].valueAt(0,0)[2] - 0. < 10e-15)