diff --git a/unittest/CMakeLists.txt b/unittest/CMakeLists.txt
index 723247bf7a77aac91be4a9de6465a372c81359fc..84ce752b838889f7c58c8e2db848645e9e9be5ad 100644
--- a/unittest/CMakeLists.txt
+++ b/unittest/CMakeLists.txt
@@ -36,3 +36,4 @@ ENDIF()
 ADD_PYTHON_UNIT_TEST("py-matrix" "unittest/python/test_matrix.py" "unittest")
 ADD_PYTHON_UNIT_TEST("py-geometry" "unittest/python/test_geometry.py" "unittest")
 ADD_PYTHON_UNIT_TEST("py-switch" "unittest/python/test_switch.py" "python/eigenpy")
+ADD_PYTHON_UNIT_TEST("py-dimensions" "unittest/python/test_dimensions.py" "python/eigenpy")
diff --git a/unittest/python/test_dimensions.py b/unittest/python/test_dimensions.py
new file mode 100644
index 0000000000000000000000000000000000000000..3ccc354b7f323cca24099d7e919dd7c220333b70
--- /dev/null
+++ b/unittest/python/test_dimensions.py
@@ -0,0 +1,14 @@
+from __future__ import print_function
+
+import eigenpy
+import numpy as np
+
+quat = eigenpy.Quaternion()
+# By default, we convert as numpy.matrix
+coeffs_vector = quat.coeffs() 
+assert len(coeffs_vector.shape) == 2
+
+# Switch to numpy.array
+eigenpy.switchToNumpyArray()
+coeffs_vector = quat.coeffs() 
+assert len(coeffs_vector.shape) == 1