Added tests for the checkoutflow module

src/requirements/testing.txt

@@ -9,6 +9,7 @@ selenium
 pytest
 pytest-django
 isort
+pytest-mock
 # PyVirtualDisplay
 # -e git+https://github.com/pretix/sauceclient.git@master#egg=sauceclient
 # travis

src/tests/presale/test_checkoutflow.py

@@ -0,0 +1,104 @@
+import pytest
+from django.test import RequestFactory
+from django.utils.timezone import now
+
+from pretix.base.models import Event, Organizer
+from pretix.multidomain.middlewares import SessionMiddleware
+from pretix.presale import checkoutflow
+
+
+@pytest.fixture
+def event():
+    o = Organizer.objects.create(name='MRMCD', slug='mrmcd')
+    e = Event.objects.create(
+        organizer=o, name='MRMCD2015', slug='2015',
+        date_from=now()
+    )
+    return e
+
+
+@pytest.fixture
+def req_with_session():
+    factory = RequestFactory()
+    r = factory.get('/')
+    SessionMiddleware().process_request(r)
+    r.session.save()
+    return r
+
+
+@pytest.mark.django_db
+def test_flow_order(event):
+    orig_flow = checkoutflow.DEFAULT_FLOW
+    checkoutflow.DEFAULT_FLOW = (
+        checkoutflow.ConfirmStep, checkoutflow.PaymentStep, checkoutflow.QuestionsStep
+    )
+    flow = checkoutflow.get_checkout_flow(event)
+    assert all(flow[i].priority <= flow[i + 1].priority for i in range(len(flow) - 1))
+    checkoutflow.DEFAULT_FLOW = orig_flow
+
+
+@pytest.mark.django_db
+def test_double_linked_list(event):
+    flow = checkoutflow.get_checkout_flow(event)
+    assert all(flow[i]._next is flow[i + 1] for i in range(len(flow) - 1))
+    assert all(flow[i + 1]._previous is flow[i] for i in range(len(flow) - 1))
+
+
+@pytest.mark.django_db
+def test_plugins_called(event, mocker):
+    from pretix.presale.signals import checkout_flow_steps
+    mocker.patch('pretix.presale.signals.checkout_flow_steps.send')
+    checkoutflow.get_checkout_flow(event)
+    checkout_flow_steps.send.assert_called_once_with(event)
+
+
+def with_mocked_step(mocker, step, event):
+    from pretix.presale.signals import checkout_flow_steps
+    mocker.patch('pretix.presale.signals.checkout_flow_steps.send')
+    checkout_flow_steps.send.return_value = [(None, step)]
+    return checkoutflow.get_checkout_flow(event)
+
+
+@pytest.mark.django_db
+def test_plugins_max_priority(event, mocker):
+    class MockingStep(checkoutflow.BaseCheckoutFlowStep):
+        identifier = 'mocking'
+        priority = 1001
+
+    with pytest.raises(ValueError):
+        with_mocked_step(mocker, MockingStep, event)
+
+
+@pytest.mark.django_db
+def test_plugin_in_order(event, mocker):
+    class MockingStep(checkoutflow.BaseCheckoutFlowStep):
+        identifier = 'mocking'
+        priority = 100
+
+    flow = with_mocked_step(mocker, MockingStep, event)
+    assert isinstance(flow[0], checkoutflow.QuestionsStep)
+    assert isinstance(flow[1], MockingStep)
+    assert isinstance(flow[2], checkoutflow.PaymentStep)
+    assert isinstance(flow[3], checkoutflow.ConfirmStep)
+
+
+@pytest.mark.django_db
+def test_step_ignored(event, mocker, req_with_session):
+    class MockingStep(checkoutflow.BaseCheckoutFlowStep):
+        identifier = 'mocking'
+        priority = 100
+
+        def is_applicable(self, request):
+            return False
+
+    flow = with_mocked_step(mocker, MockingStep, event)
+    req_with_session.event = event
+    assert flow[0].get_next_applicable(req_with_session) is flow[2]
+    assert flow[0] is flow[2].get_prev_applicable(req_with_session)
+
+
+@pytest.mark.django_db
+def test_step_first_last(event):
+    flow = checkoutflow.get_checkout_flow(event)
+    assert flow[0].get_prev_applicable(req_with_session) is None
+    assert flow[-1].get_next_applicable(req_with_session) is None