added test for rad to degree conversion with negative rad number

src/test/py/test_trigonometry.py

@@ -24,6 +24,12 @@ class MyTestCase(unittest.TestCase):
             delta *= -1
         self.assertLess(delta, 0.01)
 
+    def test_rad_negative_1_to_deg_should_be_negative_57_point_296(self):
+        delta = rad2deg(-1) - -57.296
+        if delta < 0:
+            delta *= -1
+        self.assertLess(delta, 0.01)
+
 
 if __name__ == '__main__':
     unittest.main()