add pybullet unittests.py with travis support

examples/pybullet/unittests/unittests.py

@@ -0,0 +1,46 @@
+import unittest
+import pybullet
+import time
+
+class TestPybulletMethods(unittest.TestCase):
+
+    def test_import(self):
+        import pybullet as p
+        self.assertGreater(p.getAPIVersion(), 201700000)
+
+    def test_connect_direct(self):
+        import pybullet as p
+        cid = p.connect(p.DIRECT)
+        self.assertEqual(cid,0)
+        p.disconnect()
+
+    def test_loadurdf(self):
+        import pybullet as p
+        p.connect(p.DIRECT)
+        ob = p.loadURDF("r2d2.urdf")
+        self.assertEqual(ob,0)
+        p.disconnect()
+
+    def test_rolling_friction(self):
+        import pybullet as p
+        p.connect(p.DIRECT)
+        p.loadURDF("plane.urdf")
+        sphere = p.loadURDF("sphere2.urdf",[0,0,1])
+        p.resetBaseVelocity(sphere,linearVelocity=[1,0,0])
+        p.changeDynamics(sphere,-1,linearDamping=0,angularDamping=0)
+        #p.changeDynamics(sphere,-1,rollingFriction=0)
+        p.setGravity(0,0,-10)
+        for i in range (1000):
+          p.stepSimulation()
+        vel = p.getBaseVelocity(sphere)
+        self.assertLess(vel[0][0],1e-10)
+        self.assertLess(vel[0][1],1e-10)
+        self.assertLess(vel[0][2],1e-10)
+        self.assertLess(vel[1][0],1e-10)
+        self.assertLess(vel[1][1],1e-10)
+        self.assertLess(vel[1][2],1e-10)
+        p.disconnect()
+       
+if __name__ == '__main__':
+    unittest.main()
+