diff --git a/requirements.txt b/requirements.txt
index 8173de9e..ec986f8e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -170,6 +170,7 @@ pytest-django==3.4.8
 pytest-forked==1.0.2
 pytest-runner==4.4
 pytest-sugar==0.9.2
+pytest-timeout==1.4.2
 pytest-xdist==1.27.0
 python-dateutil==2.8.0
 python-memcached==1.59
diff --git a/rowers/datautils.py b/rowers/datautils.py
index 554ea19e..08b7f5b5 100644
--- a/rowers/datautils.py
+++ b/rowers/datautils.py
@@ -60,7 +60,7 @@ def updatecp(delta,cpvalues,r,workouttype='water'):
 
     return 1
 
-def cpfit(powerdf):
+def cpfit(powerdf,fraclimit=0.0001,nmax=1000):
     # Fit the data to thee parameter CP model
     fitfunc = lambda pars,x: abs(pars[0])/(1+(x/abs(pars[2]))) + abs(pars[1])/(1+(x/abs(pars[3])))
     errfunc = lambda pars,x,y: fitfunc(pars,x)-y
@@ -96,11 +96,13 @@ def cpfit(powerdf):
 
     frac = abs(ddmin)/fitpoints.mean()
 
-    while frac>0.0001:
+    counter = 0
+    while frac>fraclimit and counter<nmax:
         fitpoints = fitpoints*(fitpoints.mean()-ddmin)/(fitpoints.mean())
         dd = fitpoints-theavpower
         ddmin = dd.min()
         frac = abs(ddmin)/fitpoints.mean()
+        counter += 1
 
     ratio = fitpoints.mean()/fitpoints0.mean()
 
@@ -111,7 +113,7 @@ def getlogarr(maxt):
     #print(maxlog10,round(maxlog10))
     aantal = 10*round(maxlog10)
     logarr = np.arange(aantal+1)/10.
-    
+
     res = []
     for la in logarr:
         try:
diff --git a/rowers/tests/test_analysis.py b/rowers/tests/test_analysis.py
index 50b0ab36..c78114b9 100644
--- a/rowers/tests/test_analysis.py
+++ b/rowers/tests/test_analysis.py
@@ -158,6 +158,8 @@ class BoxPlotTest(TestCase):
         options['userid'] = 1
         options['plotfield'] = 'spm'
         options['rankingonly'] = False
+        options['cpfit'] = 'data'
+        options['piece'] = 4
 
         session = self.c.session
         session['options'] = options
@@ -1065,6 +1067,8 @@ class WorkoutStatsTestNew(TestCase):
             'spmmax':55,
             'workmin':0,
             'workmax':1500,
+            'cpfit':'data',
+            'piece': 4,
             'includereststrokes':False,
             'modality':'all',
             'waterboattype':['1x','2x','4x'],
diff --git a/rowers/tests/test_aworkouts.py b/rowers/tests/test_aworkouts.py
index 1a9d36f4..3417c53f 100644
--- a/rowers/tests/test_aworkouts.py
+++ b/rowers/tests/test_aworkouts.py
@@ -4,6 +4,7 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 from .statements import *
+from django.db import transaction
 
 nu = datetime.datetime.now()
 
@@ -144,57 +145,59 @@ class WorkoutViewTest(TestCase):
 
     @patch('rowers.dataprep.create_engine')
     @patch('rowers.dataprep.getsmallrowdata_db')
+    @pytest.mark.django_db(transaction=True)
     def test_joins(self, mocked_sqlalchemy, mocked_getsmallrowdata_db):
-        login = self.c.login(username=self.u.username, password=self.password)
-        self.assertTrue(login)
+        with transaction.atomic():
+            login = self.c.login(username=self.u.username, password=self.password)
+            self.assertTrue(login)
 
-        url = reverse('workouts_join_select')
-        response = self.c.get(url)
-        self.assertEqual(response.status_code,200)
+            url = reverse('workouts_join_select')
+            response = self.c.get(url)
+            self.assertEqual(response.status_code,200)
 
-        d1 = self.werg1.date-datetime.timedelta(days=2)
-        d2 = self.werg2.date+datetime.timedelta(days=2)
+            d1 = self.werg1.date-datetime.timedelta(days=2)
+            d2 = self.werg2.date+datetime.timedelta(days=2)
 
-        date_form_data = {
-            'startdate': d1.strftime('%Y-%m%d'),
-            'enddate': d2.strftime('%Y-%m%d')
-            }
+            date_form_data = {
+                'startdate': d1.strftime('%Y-%m%d'),
+                'enddate': d2.strftime('%Y-%m%d')
+                }
 
-        response = self.c.post(url,date_form_data)
-        self.assertEqual(response.status_code,200)
+            response = self.c.post(url,date_form_data)
+            self.assertEqual(response.status_code,200)
 
-        url  = reverse('workouts_join_view')
+            url  = reverse('workouts_join_view')
 
-        response = self.c.get(url,follow=True)
-        self.assertEqual(response.status_code,200)
+            response = self.c.get(url,follow=True)
+            self.assertEqual(response.status_code,200)
 
-        expected_url = reverse('workouts_join_select')
-        self.assertRedirects(response,
+            expected_url = reverse('workouts_join_select')
+            self.assertRedirects(response,
                              expected_url=expected_url,
                              status_code=302,
                              target_status_code=200)
 
-        form_data = {
-            'workout_name': 'joined',
-            'set_private': False,
-            'workouts': [str(self.werg1.id),str(self.werg2.id),str(self.werg3.id)],
+            form_data = {
+                'workout_name': 'joined',
+                'set_private': False,
+                'workouts': [str(self.werg1.id),str(self.werg2.id),str(self.werg3.id)],
             }
 
-        form = WorkoutMultipleCompareForm(form_data)
-        self.assertTrue(form.is_valid())
+            form = WorkoutMultipleCompareForm(form_data)
+            self.assertTrue(form.is_valid())
 
-        form = WorkoutJoinParamForm(form_data)
-        self.assertTrue(form.is_valid())
+            form = WorkoutJoinParamForm(form_data)
+            self.assertTrue(form.is_valid())
 
-        response = self.c.post(url,form_data,follow=True)
-        self.assertEqual(response.status_code,200)
+            response = self.c.post(url,form_data,follow=True)
+            self.assertEqual(response.status_code,200)
 
-        expected_url = reverse(self.r.defaultlandingpage,
+            expected_url = reverse(self.r.defaultlandingpage,
                                kwargs = {
                                    'id':encoder.encode_hex(12)
                                    })
 
-        self.assertRedirects(response,
+            self.assertRedirects(response,
                              expected_url=expected_url,
                              status_code=302,target_status_code=200)
 
@@ -485,27 +488,29 @@ class WorkoutViewTest(TestCase):
     @patch('rowers.dataprep.create_engine')
     @patch('rowers.dataprep.getsmallrowdata_db')
     @patch('rowers.dataprep.getrowdata_db',side_effect=mocked_getrowdata_db)
+    @pytest.mark.django_db(transaction=True)
     def test_workout_split(self, mocked_sqlalchemy, mocked_getsmallrowdata_db,
                            mocked_getrowdata_db):
-        login = self.c.login(username=self.u.username, password=self.password)
-        self.assertTrue(login)
+        with transaction.atomic():
+            login = self.c.login(username=self.u.username, password=self.password)
+            self.assertTrue(login)
 
-        url  = reverse('workout_split_view',kwargs={'id':encoder.encode_hex(self.werg1.id)})
+            url  = reverse('workout_split_view',kwargs={'id':encoder.encode_hex(self.werg1.id)})
 
-        response = self.c.get(url)
-        self.assertEqual(response.status_code,200)
+            response = self.c.get(url)
+            self.assertEqual(response.status_code,200)
 
-        form_data = {
-            'splittime': '2:00',
-            'splitmode': ['keep original','keep first','keep second']
-            }
+            form_data = {
+                'splittime': '2:00',
+                'splitmode': ['keep original','keep first','keep second']
+                }
 
-        form = WorkoutSplitForm(form_data)
+            form = WorkoutSplitForm(form_data)
 
-        self.assertTrue(form.is_valid())
+            self.assertTrue(form.is_valid())
 
-        response = self.c.post(url, form_data,follow=True)
-        self.assertEqual(response.status_code,200)
+            response = self.c.post(url, form_data,follow=True)
+            self.assertEqual(response.status_code,200)
 
     @patch('rowers.dataprep.create_engine')
     @patch('rowers.dataprep.getrowdata_db',side_effect=mocked_getrowdata_db)