From: Hugo Smett <hsmett@hybird.org>
Date: Wed, 28 Mar 2018 14:02:29 +0200
Subject: Fix tests for Django 2.0

---
 tests/models.py | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/tests/models.py b/tests/models.py
index a1e616a..38616c3 100644
--- a/tests/models.py
+++ b/tests/models.py
@@ -18,16 +18,16 @@ class TestModelWithDecimalField(DirtyFieldsMixin, models.Model):
 
 
 class TestModelWithForeignKey(DirtyFieldsMixin, models.Model):
-    fkey = models.ForeignKey(TestModel)
+    fkey = models.ForeignKey(TestModel, on_delete=models.CASCADE)
 
 
 class TestMixedFieldsModel(DirtyFieldsMixin, models.Model):
-    fkey = models.ForeignKey(TestModel)
+    fkey = models.ForeignKey(TestModel, on_delete=models.CASCADE)
     characters = models.CharField(blank=True, max_length=80)
 
 
 class TestModelWithOneToOneField(DirtyFieldsMixin, models.Model):
-    o2o = models.OneToOneField(TestModel)
+    o2o = models.OneToOneField(TestModel, on_delete=models.CASCADE)
 
 
 class TestModelWithNonEditableFields(DirtyFieldsMixin, models.Model):
@@ -38,7 +38,7 @@ class TestModelWithNonEditableFields(DirtyFieldsMixin, models.Model):
 
 
 class TestModelWithSelfForeignKey(DirtyFieldsMixin, models.Model):
-    fkey = models.ForeignKey("self", blank=True, null=True)
+    fkey = models.ForeignKey("self", blank=True, null=True, on_delete=models.CASCADE)
 
 
 class OrdinaryTestModel(models.Model):
@@ -47,7 +47,7 @@ class OrdinaryTestModel(models.Model):
 
 
 class OrdinaryTestModelWithForeignKey(models.Model):
-    fkey = models.ForeignKey(OrdinaryTestModel)
+    fkey = models.ForeignKey(OrdinaryTestModel, on_delete=models.CASCADE)
 
 
 class SubclassModel(TestModel):
@@ -108,8 +108,9 @@ class TestModelWithoutM2MCheck(DirtyFieldsMixin, models.Model):
 
 
 class TestDoubleForeignKeyModel(DirtyFieldsMixin, models.Model):
-    fkey1 = models.ForeignKey(TestModel)
-    fkey2 = models.ForeignKey(TestModel, null=True, related_name='fkey2')
+    fkey1 = models.ForeignKey(TestModel, on_delete=models.CASCADE)
+    fkey2 = models.ForeignKey(TestModel, null=True, related_name='fkey2',
+                              on_delete=models.CASCADE)
 
 
 if is_postgresql_env_with_json_field():
@@ -128,7 +129,8 @@ class TestModelWithSpecifiedFields(DirtyFieldsMixin, models.Model):
 class TestModelWithSpecifiedFieldsAndForeignKey(DirtyFieldsMixin, models.Model):
     boolean1 = models.BooleanField(default=True)
     boolean2 = models.BooleanField(default=True)
-    fk_field = models.OneToOneField(TestModel, null=True)
+    fk_field = models.OneToOneField(TestModel, null=True,
+                                    on_delete=models.CASCADE)
     FIELDS_TO_CHECK = ['fk_field_id']
 
 
