From ba163fe943b5456883dff90b60ce3c1446230e8b Mon Sep 17 00:00:00 2001
From: Gergely Polonkai <gergely.polonkai@ericsson.com>
Date: Wed, 21 Oct 2015 15:56:12 +0200
Subject: [PATCH] Create system check for MAX_DUCK_LEVEL setting

---
 booking/__init__.py |  5 +++++
 booking/apps.py     | 48 +++++++++++++++++++++++++++++++++++++++++++++
 booking/tests.py    | 40 +++++++++++++++++++++++++++----------
 3 files changed, 83 insertions(+), 10 deletions(-)
 create mode 100644 booking/apps.py

diff --git a/booking/__init__.py b/booking/__init__.py
index e69de29..41279d5 100644
--- a/booking/__init__.py
+++ b/booking/__init__.py
@@ -0,0 +1,5 @@
+"""
+Booking module of the Duck Booking Tool
+"""
+
+default_app_config = 'booking.apps.BookingConfig'
diff --git a/booking/apps.py b/booking/apps.py
new file mode 100644
index 0000000..9b4e553
--- /dev/null
+++ b/booking/apps.py
@@ -0,0 +1,48 @@
+# -*- coding: utf-8
+"""
+App config for the booking module of the Duck Booking Tool. This module
+is currently needed for the MAX_DUCK_LEVEL system check.
+"""
+
+from django.apps import AppConfig
+from django.conf import settings
+from django.core.checks import Error, register
+from django.core.exceptions import ImproperlyConfigured
+
+@register()
+def max_level_check(app_configs, **kwargs):
+    """
+    System check to see if MAX_DUCK_LEVEL has a sane value (non-zero,
+    positive integer)
+    """
+
+    errors = []
+
+    if not hasattr(settings, 'MAX_DUCK_LEVEL'):
+        errors.append(
+            Error(
+                'MAX_DUCK_LEVEL is not set!',
+                id='booking.E001'
+            )
+        )
+    else:
+        if settings.MAX_DUCK_LEVEL <= 0:
+            errors.append(
+                Error(
+                    'MAX_DUCK_LEVEL should be greater than zero!',
+                    id='booking.E002'
+                )
+            )
+
+        if not isinstance(settings.MAX_DUCK_LEVEL, int):
+            errors.append(
+                Error(
+                    'MAX_DUCK_LEVEL must be an integer!',
+                    id='booking.E003'
+                )
+            )
+
+    return errors
+
+class BookingConfig(AppConfig):
+    name = 'booking'
diff --git a/booking/tests.py b/booking/tests.py
index 8d6f4b0..e9a7f47 100644
--- a/booking/tests.py
+++ b/booking/tests.py
@@ -7,13 +7,14 @@ import datetime
 
 from django.conf import settings
 from django.contrib.auth.models import User
-from django.test import TestCase, Client
+from django.test import TestCase, Client, override_settings
 from django.utils import timezone
 
 from .ducklevel import level_to_up_minutes, level_to_down_minutes, minutes_to_level
 from .templatetags import booking_tags
 from .models import Duck, Competence, DuckCompetence, Species, \
                     Location, Booking, DuckName, DuckNameVote
+from .apps import max_level_check
 
 class FrontTest(TestCase):
     """
@@ -79,15 +80,6 @@ class DuckCompLevelTest(TestCase):
                                                       up_minutes=0,
                                                       down_minutes=0)
 
-    def test_sane_max(self):
-        """
-        Test if the MAX_DUCK_LEVEL setting has a sane value
-        """
-
-        self.assertGreater(
-            settings.MAX_DUCK_LEVEL, 0,
-            msg="MAX_DUCK_LEVEL must be greater than zero!")
-
     def test_max_minutes(self):
         """
         Test if level can not go above settings.MAX_DUCK_LEVEL)
@@ -491,3 +483,31 @@ class StrTest(TestCase):
 
         self.assertEquals("First Duck booked by test for Testing since {0}".format(start),
                           booking.__str__())
+
+class SystemCheckTest(TestCase):
+    @override_settings()
+    def test_max_duck_level_missing(self):
+        del settings.MAX_DUCK_LEVEL
+
+        errors = max_level_check(None)
+
+        self.assertGreater(
+            len([e for e in errors if e.id == 'booking.E001']),
+            0)
+
+    def test_max_duck_level_illegal(self):
+        with self.settings(MAX_DUCK_LEVEL=0):
+            errors = max_level_check(None)
+
+            self.assertGreater(
+                len([e for e in errors if e.id == 'booking.E002']),
+                0
+            )
+
+        with self.settings(MAX_DUCK_LEVEL=1.1):
+            errors = max_level_check(None)
+
+            self.assertGreater(
+                len([e for e in errors if e.id == 'booking.E003']),
+                0
+            )