diff --git a/kfet/models.py b/kfet/models.py
index 88626729..2594282d 100644
--- a/kfet/models.py
+++ b/kfet/models.py
@@ -557,7 +557,7 @@ class Operation(models.Model):
         templates = {
                 self.PURCHASE: "{nb} {article.name} ({amount}€)",
                 self.DEPOSIT: "charge ({amount})",
-                self.WITHDRAW: "retrait  ({amount})",
+                self.WITHDRAW: "retrait ({amount})",
                 self.INITIAL: "initial ({amount})",
             }
         return templates[self.type].format(nb=self.article_nb,
diff --git a/kfet/statistic.py b/kfet/statistic.py
index e3c89a6d..dc329a0c 100644
--- a/kfet/statistic.py
+++ b/kfet/statistic.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 from django.utils import timezone
+from django.db.models import Sum
 
 
 # donne le nom des jours d'une liste de dates
@@ -28,6 +29,7 @@ def monthnames(dates):
         names[i] = dates[i].strftime("%B")
     return names
 
+
 # rend les dates des nb derniers jours
 # dans l'ordre chronologique
 # aujourd'hui compris
@@ -55,7 +57,7 @@ def lastmonths(nb):
     this_year = first_month_day.year
     this_month = first_month_day.month
     for i in range(1, nb+1):
-        month = ((this_month - 1  - (nb - i)) % 12) + 1
+        month = ((this_month - 1 - (nb - i)) % 12) + 1
         year = this_year + (nb - i) // 12
         first_days[i] = timezone.datetime(year=year,
                                           month=month,
@@ -91,7 +93,5 @@ def this_morning():
 # Étant donné un queryset d'operations
 # rend la somme des article_nb
 def tot_ventes(queryset):
-    res = 0
-    for op in queryset:
-        res += op.article_nb
-    return res
+    res = queryset.aggregate(Sum('article_nb'))['article_nb__sum']
+    return res and res or 0
diff --git a/kfet/tests.py b/kfet/tests.py
index 98558001..5bea7afa 100644
--- a/kfet/tests.py
+++ b/kfet/tests.py
@@ -2,143 +2,4 @@
 
 from django.test import TestCase
 
-from kfet.models import Account
-from gestioncof.models import CofProfile, User
-
-
-
-names = ['Abelardus',
-          'Abrahamus',
-          'Acacius',
-          'Accius',
-          'Achaicus',
-          'Achill',
-          'Achilles',
-          'Achilleus',
-          'Acrisius',
-          'Actaeon',
-          'Acteon',
-          'Adalricus',
-          'Adelfonsus',
-          'Adelphus',
-          'Adeodatus',
-          'Adolfus',
-          'Adolphus',
-          'Adrastus',
-          'Adrianus',
-          'Ægidius',
-          'Ælia',
-          'Ælianus',
-          'Æmilianus',
-          'Æmilius',
-          'Aeneas',
-          'Æolus',
-          'Æschylus',
-          'Æson',
-          'Æsop',
-          'Æther',
-          'Ætius',
-          'Agapetus',
-          'Agapitus',
-          'Agapius',
-          'Agathangelus',
-          'Aigidius',
-          'Aiolus',
-          'Ajax',
-          'Alair',
-          'Alaricus',
-          'Albanus',
-          'Alberic',
-          'Albericus',
-          'Albertus',
-          'Albinus',
-          'Albus',
-          'Alcaeus',
-          'Alcander',
-          'Alcimus',
-          'Alcinder',
-          'Alerio',
-          'Alexandrus',
-          'Alexis',
-          'Alexius',
-          'Alexus',
-          'Alfonsus',
-          'Alfredus',
-          'Almericus',
-          'Aloisius',
-          'Aloysius',
-          'Alphaeus',
-          'Alpheaus',
-          'Alpheus',
-          'Alphoeus',
-          'Alphonsus',
-          'Alphonzus',
-          'Alvinius',
-          'Alvredus',
-          'Amadeus',
-          'Amaliricus',
-          'Amandus',
-          'Amantius',
-          'Amarandus',
-          'Amaranthus',
-          'Amatus',
-          'Ambrosianus',
-          'Ambrosius',
-          'Amedeus',
-          'Americus',
-          'Amlethus',
-          'Amletus',
-          'Amor',
-          'Ampelius',
-          'Amphion',
-          'Anacletus',
-          'Anastasius',
-          'Anastatius',
-          'Anastius',
-          'Anatolius',
-          'Androcles',
-          'Andronicus',
-          'Anencletus',
-          'Angelicus',
-          'Angelus',
-          'Anicetus',
-          'Antigonus',
-          'Antipater',
-          'Antoninus',
-          'Antonius',
-          'Aphrodisius',
-          'Apollinaris']
-
-
-# Ne pas supprimer, peut être utile pour regénérer 
-# d'autres fixtures à l'avenir
-class TestFoo(TestCase):
-    fixtures = ['users', 'sites', 'gestion', 'articles']
-
-    def test_foo(self):
-        pass
-        # for name in names:
-        #     user = User(username=name,
-        #                 last_name='Romain',
-        #                 first_name=name)
-        #     user.email = '{}.{}@ens.fr'.format(user.first_name, user.last_name)
-        #     user.save()
-
-        # galois_trigrammes = map('{:03d}'.format, range(40))
-        # galois = CofProfile.objects.filter(user__last_name='Gaulois')
-
-        # romains_trigrammes = map(lambda x: str(100+x), range(40))
-        # romains = CofProfile.objects.filter(user__last_name='Romain')
-
-        # for t, c in zip(galois_trigrammes, galois):
-        #     Account.objects.create(cofprofile=c, trigramme=t)
-        # for t, c in zip(romains_trigrammes, romains):
-        #     Account.objects.create(cofprofile=c, trigramme=t)
-
-
-# class TestBar(TestCase):
-#     fixtures = ['users', 'sites', 'gestion', 'articles', 'groups', 'accounts']
-
-
-#     def test_foo(self):
-#         pass
+# Écrire les tests ici
diff --git a/kfet/views.py b/kfet/views.py
index 24fa8c0d..586f3d8b 100644
--- a/kfet/views.py
+++ b/kfet/views.py
@@ -2020,7 +2020,7 @@ class ObjectResumeStat(DetailView):
     """
     template_name = 'kfet/object_stat_resume.html'
     context_object_name = ''
-    id_prefix = 'id_a_definir'
+    id_prefix = ''
     # nombre de vues à résumer
     nb_stat = 2
     # Le combienième est celui par defaut ?