Add official support for Django 2.2.

.coveragerc

@@ -1,3 +1,8 @@
 [run]
 source = picklefield
 branch = True
+
+[report]
+exclude_lines =
+    pragma: no cover
+    except ImportError:

.travis.yml

@@ -1,54 +1,24 @@
-dist: trusty
+dist: bionic
 sudo: false
 language: python
-env:
-  matrix:
-  - TOXENV=flake8
-  - TOXENV=isort
 cache: pip
-matrix:
+python:
+  - 2.7
+  - 3.5
+  - 3.6
+  - 3.7
+  - 3.8
+stages:
+  - lint
+  - test
+jobs:
   fast_finish: true
   include:
-  - python: 2.7
-    env: TOXENV=py27-1.11
-  - python: 3.4
-    env: TOXENV=py34-1.11
-  - python: 3.4
-    env: TOXENV=py34-2.0
-  - python: 3.5
-    env: TOXENV=py35-1.11
-  - python: 3.5
-    env: TOXENV=py35-2.0
-  - python: 3.5
-    env: TOXENV=py35-2.1
-  - python: 3.5
-    env: TOXENV=py35-master
-  - python: 3.6
-    env: TOXENV=py36-1.11
-  - python: 3.6
-    env: TOXENV=py36-2.0
-  - python: 3.6
-    env: TOXENV=py36-2.1
-  - python: 3.6
-    env: TOXENV=py36-master
-  - python: 3.7
-    env: TOXENV=py37-2.0
-    dist: xenial
-    sudo: true
-  - python: 3.7
-    env: TOXENV=py37-2.1
-    dist: xenial
-    sudo: true
-  - python: 3.7
-    env: TOXENV=py37-master
-    dist: xenial
-    sudo: true
-  allow_failures:
-  - env: TOXENV=py35-master
-  - env: TOXENV=py36-master
-  - env: TOXENV=py37-master
+    - { stage: lint, env: TOXENV=flake8, python: 3.6 }
+    - { stage: lint, env: TOXENV=isort, python: 3.6 }
+
 install:
-- pip install tox coveralls
+- pip install tox coveralls tox-travis
 script:
 - tox
 after_success:

picklefield/fields.py

@@ -4,17 +4,17 @@
 from copy import deepcopy
 from zlib import compress, decompress
 
-import django
+from django import VERSION as DJANGO_VERSION
 from django.core import checks
 from django.db import models
 from django.utils.encoding import force_text
 
 from .constants import DEFAULT_PROTOCOL
 
 try:
-    from cPickle import loads, dumps
+    from cPickle import loads, dumps  # pragma: no cover
 except ImportError:
-    from pickle import loads, dumps
+    from pickle import loads, dumps  # pragma: no cover
 
 
 class PickledObject(str):
@@ -158,7 +158,7 @@ def to_python(self, value):
                 value = dbsafe_decode(value, self.compress)
             except Exception:
                 # If the value is a definite pickle; and an error is raised in
-                # de-pickling it should be allowed to propogate.
+                # de-pickling it should be allowed to propagate.
                 if isinstance(value, PickledObject):
                     raise
             else:
@@ -170,12 +170,12 @@ def pre_save(self, model_instance, add):
         value = super(PickledObjectField, self).pre_save(model_instance, add)
         return wrap_conflictual_object(value)
 
-    if django.VERSION < (2, 0):
-        def from_db_value(self, value, expression, connection, context):
-            return self.to_python(value)
+    if DJANGO_VERSION < (2, 0):
+        def from_db_value(self, value, expression, connection, context):  # pragma: no cover
+            return self.to_python(value)  # pragma: no cover
     else:
-        def from_db_value(self, value, expression, connection):
-            return self.to_python(value)
+        def from_db_value(self, value, expression, connection):  # pragma: no cover
+            return self.to_python(value)  # pragma: no cover
 
     def get_db_prep_value(self, value, connection=None, prepared=False):
         """

setup.py

@@ -21,8 +21,7 @@
         'Environment :: Web Environment',
         'Framework :: Django',
         'Framework :: Django :: 1.11',
-        'Framework :: Django :: 2.0',
-        'Framework :: Django :: 2.1',
+        'Framework :: Django :: 2.2',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: MIT License',
         'Operating System :: OS Independent',
@@ -34,6 +33,7 @@
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
         'Topic :: Software Development :: Libraries :: Application Frameworks',
         'Topic :: Software Development :: Libraries :: Python Modules',
     ],

tests/models.py

@@ -27,6 +27,7 @@ class TestingModel(models.Model):
     default_pickle_field = PickledObjectField(default=(D1, S1, T1, L1))
     callable_pickle_field = PickledObjectField(default=date.today)
     non_copying_field = PickledObjectField(copy=False, default=TestCopyDataType('boom!'))
+    nullable_pickle_field = PickledObjectField(null=True)
 
 
 class MinimalTestingModel(models.Model):

tests/tests.py

@@ -14,6 +14,11 @@
     TestCustomDataType, TestingModel,
 )
 
+try:
+    from unittest.mock import patch  # pragma: no cover
+except ImportError:
+    from mock import patch  # pragma: no cover
+
 
 class PickledObjectFieldTests(TestCase):
     def setUp(self):
@@ -35,6 +40,7 @@ def test_data_integrity(self):
             # the same data, even thought it's stored differently in the DB.
             self.assertEqual(value, model_test.pickle_field)
             self.assertEqual(value, model_test.compressed_pickle_field)
+            self.assertIsNone(model_test.nullable_pickle_field)
             # Make sure we can also retrieve the model
             model_test.save()
             model_test.delete()
@@ -181,6 +187,21 @@ def test_empty_strings_not_allowed(self):
         with self.assertRaises(IntegrityError):
             MinimalTestingModel.objects.create()
 
+    def test_decode_error(self):
+        def mock_decode_error(*args, **kwargs):
+            raise Exception()
+
+        model = MinimalTestingModel.objects.create(pickle_field={'foo': 'bar'})
+        model.save()
+
+        self.assertEqual(
+            {'foo': 'bar'}, MinimalTestingModel.objects.get(pk=model.pk).pickle_field
+        )
+
+        with patch('picklefield.fields.dbsafe_decode', mock_decode_error):
+            encoded_value = dbsafe_encode({'foo': 'bar'})
+            self.assertEqual(encoded_value, MinimalTestingModel.objects.get(pk=model.pk).pickle_field)
+
 
 @isolate_apps('tests')
 class PickledObjectFieldCheckTests(SimpleTestCase):

tox.ini

@@ -5,27 +5,36 @@ envlist =
     flake8,
     isort,
     py27-1.11,
-    py34-{1.11,2.0},
-    py35-{1.11,2.0,2.1,master},
-    py36-{1.11,2.0,2.1,master},
-    py37-{1.11,2.0,2.1,master}
+    py35-{1.11,2.2},
+    py36-{1.11,2.2,master},
+    py37-{1.11,2.2,master},
+    py38-{2.2,master},
+
+[tox:travis]
+2.7 = py27
+3.5 = py35
+3.6 = py36
+3.7 = py37
+3.8 = py38
 
 [testenv]
 basepython =
     py27: python2.7
-    py34: python3.4
     py35: python3.5
     py36: python3.6
     py37: python3.7
+    py38: python3.8
 usedevelop = true
 commands =
-    {envpython} -R -Wonce {envbindir}/coverage run -m django test -v2 --settings=tests.settings {posargs}
-    coverage report
+    {envpython} -R -Wonce {envbindir}/coverage run --branch -m django test -v2 --settings=tests.settings {posargs}
+    coverage report -m
 deps =
+    py27: mock
     coverage
     1.11: Django>=1.11,<2.0
     2.0: Django>=2.0,<2.1
     2.1: Django>=2.1,<2.2
+    2.2: Django>=2.2,<3.0
     master: https://github.com/django/django/archive/master.tar.gz
 
 [testenv:flake8]