diff --git a/hysop/operator/tests/test_poisson.py b/hysop/operator/tests/test_poisson.py
index 70e2c389f4e0a50a6c935c16df8e41f5d50cc4a0..9659ad22a721df44e8abded6d828faffd9d49f73 100644
--- a/hysop/operator/tests/test_poisson.py
+++ b/hysop/operator/tests/test_poisson.py
@@ -1,4 +1,5 @@
-import random, primefac
+import random
+import primefac
 import itertools as it
 import sympy as sm
 
@@ -380,7 +381,7 @@ class TestPoissonOperator(object):
             self.test_2d_float64(max_runs=max_2d_runs)
             if __ENABLE_LONG_TESTS__:
                 self.test_3d_float64(max_runs=max_3d_runs)
-                self.test_4d_float32(max_runs=max_4d_runs)
+                self.test_4d_float64(max_runs=max_4d_runs)
 
 
 if __name__ == '__main__':