diff --git a/python/build_pyqmckl.sh b/python/build_pyqmckl.sh
index 0dbd8fe..4736206 100755
--- a/python/build_pyqmckl.sh
+++ b/python/build_pyqmckl.sh
@@ -3,6 +3,8 @@
 set -e
 set -x
 
+cp ../include/qmckl.h .
+
 # check if qmckl header exists
 if [[ ! -f 'qmckl.h' ]]; then
   echo "qmckl.h NOT FOUND"
diff --git a/python/test/test_api.py b/python/test/test_api.py
index 1d55690..4efb9cc 100644
--- a/python/test/test_api.py
+++ b/python/test/test_api.py
@@ -1,11 +1,52 @@
-import pyqmckl as pq
+""" 
+This is the test of the Python API of the QMCkl library.
+It is the `bench_mos.c` C code adapted from the `qmckl_bench`
+repo and translated into Python with some modifications.
+"""
 
-from data.data import coord
 from os.path import join
+import time
+
+import pyqmckl as pq
+from data.data import coord
+
+
+walk_num  = 100
+elec_num  = 158
+
+ITERMAX = 10
 
 ctx = pq.qmckl_context_create()
 
 fname = join('data', 'Alz_small.h5')
 
 rc = pq.qmckl_trexio_read(ctx, fname)
+assert rc==0
 print(pq.qmckl_string_of_error(rc))
+
+rc = pq.qmckl_set_electron_walk_num(ctx, walk_num)
+assert rc==0
+
+rc, mo_num = pq.qmckl_get_mo_basis_mo_num(ctx)
+assert rc==0
+
+rc = pq.qmckl_set_electron_coord(ctx, 'T', coord)
+assert rc==0
+
+size_max = 5*walk_num*elec_num*mo_num
+
+
+
+rc, mo_vgl = pq.qmckl_get_mo_basis_mo_vgl(ctx, size_max)
+assert rc==0
+
+start = time.clock_gettime_ns(time.CLOCK_REALTIME)
+
+for _ in range(ITERMAX):
+    rc, mo_vgl_in = pq.qmckl_get_mo_basis_mo_vgl_inplace(ctx, size_max)
+    assert rc==0
+
+end = time.clock_gettime_ns(time.CLOCK_REALTIME)
+
+print(f'Time for the calculation of 1 step : {(end-start)*.000001/ITERMAX} ms')
+