diff --git a/tests/test_derivative.py b/tests/test_derivative.py
index 8f09222..e5ab637 100644
--- a/tests/test_derivative.py
+++ b/tests/test_derivative.py
@@ -16,14 +16,14 @@
 
 
 def rosenbrock(input_value, output_shape):
-    size = np.product(output_shape)
+    size = np.prod(output_shape)
     values = [rosen(input_value + i * 0.01) for i in range(size)]
     output = np.array(values).reshape(output_shape)
     return output
 
 
 def rosenbrock_der(input_value, output_shape):
-    size = np.product(output_shape)
+    size = np.prod(output_shape)
     input_shape = input_value.shape
     values = [rosen_der(input_value + i * 0.01) for i in range(size)]
     # The input shape is the "deepest" dimension(s), i.e. expect