python: skip numpy tests if it's not installed.

src/python/magnum/test/test_math_numpy.py

@@ -28,7 +28,10 @@ import unittest
 from magnum import *
 from magnum import math
 
-import numpy as np
+try:
+    import numpy as np
+except ModuleNotFoundError:
+    raise unittest.SkipTest("numpy not installed")
 
 class Vector(unittest.TestCase):
     def test_from_numpy(self):

src/python/magnum/test/test_scenegraph_numpy.py

@@ -23,13 +23,17 @@
 #   DEALINGS IN THE SOFTWARE.
 #
 
-import numpy as np
 import unittest
 
 from magnum import *
 from magnum import scenegraph
 from magnum.scenegraph.matrix import Object3D, Scene3D
 
+try:
+    import numpy as np
+except ModuleNotFoundError:
+    raise unittest.SkipTest("numpy not installed")
+
 class Object(unittest.TestCase):
     def test_transformation(self):
         scene = Scene3D()