Fixing error on points_hz template tag for uninitialized user.

* Implemented initial test cases.
* Update .travis.yml to install required SQLite packages for testing.

.travis.yml

@@ -12,6 +12,9 @@ service:
 
 addons:
   postgresql: 9.5
+  apt:
+    packages:
+    - libsqlite3-mod-spatialite
 
 before_install:
   - export PYTHONPATH=$HOME/builds/audaciouscode/pdk

models.py

@@ -41,7 +41,10 @@ def install_supports_jsonfield():
     global DB_SUPPORTS_JSON # pylint: disable=global-statement
 
     if True and DB_SUPPORTS_JSON is None:
-        DB_SUPPORTS_JSON = connection.pg_version >= 90400
+        try:
+            DB_SUPPORTS_JSON = connection.pg_version >= 90400
+        except AttributeError:
+            DB_SUPPORTS_JSON = False
 
     return DB_SUPPORTS_JSON
 

templates/tests/point_hz_test.txt

@@ -0,0 +1,2 @@
+{% load passive_data_kit %}
+{% point_hz source %}

templatetags/passive_data_kit.py

@@ -99,6 +99,9 @@ def render(self, context):
 
         frequency = source.point_frequency()
 
+        if frequency is None:
+            frequency = 0
+
         value = "{:10.3f}".format(frequency) + " Hz"
 
         if frequency < 1.0:

test_templatetags.py

@@ -0,0 +1,20 @@
+from django.template.loader import render_to_string
+from django.test import TestCase
+
+from .models import DataSource
+
+class PointsHzTestCase(TestCase):
+    def setUp(self):
+        DataSource.objects.create(name='PointsHz Test User', identifier='points-hz-test')
+
+    def test_tests_working(self):
+        context = {
+            'source': DataSource.objects.get(identifier='points-hz-test') 
+        }
+
+        result = render_to_string('tests/point_hz_test.txt', context)
+
+        self.assertEqual('<span data-toggle="tooltip" data-placement="top" title="     0.000 samples per week">     0.000 mHz</span>', result.strip())
+
+    def tearDown(self):
+        DataSource.objects.get(identifier='points-hz-test').delete()

travis_settings.py

@@ -72,6 +72,10 @@
     }
 }
 
+if 'test' in sys.argv or 'test_coverage' in sys.argv: #Covers regular testing and django-coverage
+    DATABASES['default']['ENGINE'] = 'django.contrib.gis.db.backends.spatialite'
+    SPATIALITE_LIBRARY_PATH = 'mod_spatialite'
+
 # Internationalization
 # https://docs.djangoproject.com/en/1.8/topics/i18n/