diff --git a/tests/modeltests/custom_pk/fields.py b/tests/modeltests/custom_pk/fields.py
index 319e42f974b..2eeb80e6ace 100644
--- a/tests/modeltests/custom_pk/fields.py
+++ b/tests/modeltests/custom_pk/fields.py
@@ -3,6 +3,7 @@ import string
 
 from django.db import models
 
+
 class MyWrapper(object):
     def __init__(self, value):
         self.value = value
diff --git a/tests/modeltests/custom_pk/models.py b/tests/modeltests/custom_pk/models.py
index 84e6480af9d..ff2f2bac1ba 100644
--- a/tests/modeltests/custom_pk/models.py
+++ b/tests/modeltests/custom_pk/models.py
@@ -40,138 +40,3 @@ class Bar(models.Model):
 class Foo(models.Model):
     bar = models.ForeignKey(Bar)
 
-__test__ = {'API_TESTS':"""
->>> dan = Employee(employee_code=123, first_name='Dan', last_name='Jones')
->>> dan.save()
->>> Employee.objects.all()
-[<Employee: Dan Jones>]
-
->>> fran = Employee(employee_code=456, first_name='Fran', last_name='Bones')
->>> fran.save()
->>> Employee.objects.all()
-[<Employee: Fran Bones>, <Employee: Dan Jones>]
-
->>> Employee.objects.get(pk=123)
-<Employee: Dan Jones>
->>> Employee.objects.get(pk=456)
-<Employee: Fran Bones>
->>> Employee.objects.get(pk=42)
-Traceback (most recent call last):
-    ...
-DoesNotExist: Employee matching query does not exist.
-
-# Use the name of the primary key, rather than pk.
->>> Employee.objects.get(employee_code__exact=123)
-<Employee: Dan Jones>
-
-# pk can be used as a substitute for the primary key.
->>> Employee.objects.filter(pk__in=[123, 456])
-[<Employee: Fran Bones>, <Employee: Dan Jones>]
-
-# The primary key can be accessed via the pk property on the model.
->>> e = Employee.objects.get(pk=123)
->>> e.pk
-123
-
-# Or we can use the real attribute name for the primary key:
->>> e.employee_code
-123
-
-# Fran got married and changed her last name.
->>> fran = Employee.objects.get(pk=456)
->>> fran.last_name = 'Jones'
->>> fran.save()
->>> Employee.objects.filter(last_name__exact='Jones')
-[<Employee: Dan Jones>, <Employee: Fran Jones>]
->>> emps = Employee.objects.in_bulk([123, 456])
->>> emps[123]
-<Employee: Dan Jones>
-
->>> b = Business(name='Sears')
->>> b.save()
->>> b.employees.add(dan, fran)
->>> b.employees.all()
-[<Employee: Dan Jones>, <Employee: Fran Jones>]
->>> fran.business_set.all()
-[<Business: Sears>]
->>> Business.objects.in_bulk(['Sears'])
-{u'Sears': <Business: Sears>}
-
->>> Business.objects.filter(name__exact='Sears')
-[<Business: Sears>]
->>> Business.objects.filter(pk='Sears')
-[<Business: Sears>]
-
-# Queries across tables, involving primary key
->>> Employee.objects.filter(business__name__exact='Sears')
-[<Employee: Dan Jones>, <Employee: Fran Jones>]
->>> Employee.objects.filter(business__pk='Sears')
-[<Employee: Dan Jones>, <Employee: Fran Jones>]
-
->>> Business.objects.filter(employees__employee_code__exact=123)
-[<Business: Sears>]
->>> Business.objects.filter(employees__pk=123)
-[<Business: Sears>]
->>> Business.objects.filter(employees__first_name__startswith='Fran')
-[<Business: Sears>]
-
-# Primary key may be unicode string
->>> bus = Business(name=u'jaźń')
->>> bus.save()
-
-# The primary key must also obviously be unique, so trying to create a new
-# object with the same primary key will fail.
->>> try:
-...    sid = transaction.savepoint()
-...    Employee.objects.create(employee_code=123, first_name='Fred', last_name='Jones')
-...    transaction.savepoint_commit(sid)
-... except Exception, e:
-...    if isinstance(e, IntegrityError):
-...        transaction.savepoint_rollback(sid)
-...        print "Pass"
-...    else:
-...        print "Fail with %s" % type(e)
-Pass
-
-# Regression for #10785 -- Custom fields can be used for primary keys.
->>> new_bar = Bar.objects.create()
->>> new_foo = Foo.objects.create(bar=new_bar)
-
-# FIXME: This still doesn't work, but will require some changes in
-# get_db_prep_lookup to fix it.
-# >>> f = Foo.objects.get(bar=new_bar.pk)
-# >>> f == new_foo
-# True
-# >>> f.bar == new_bar
-# True
-
->>> f = Foo.objects.get(bar=new_bar)
->>> f == new_foo
-True
->>> f.bar == new_bar
-True
-
-"""}
-
-# SQLite lets objects be saved with an empty primary key, even though an
-# integer is expected. So we can't check for an error being raised in that case
-# for SQLite. Remove it from the suite for this next bit.
-if settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'] != 'django.db.backends.sqlite3':
-    __test__["API_TESTS"] += """
-# The primary key must be specified, so an error is raised if you try to create
-# an object without it.
->>> try:
-...     sid = transaction.savepoint()
-...     Employee.objects.create(first_name='Tom', last_name='Smith')
-...     print 'hello'
-...     transaction.savepoint_commit(sid)
-...     print 'hello2'
-... except Exception, e:
-...     if isinstance(e, IntegrityError):
-...         transaction.savepoint_rollback(sid)
-...         print "Pass"
-...     else:
-...         print "Fail with %s" % type(e)
-Pass
-
-"""
diff --git a/tests/modeltests/custom_pk/tests.py b/tests/modeltests/custom_pk/tests.py
new file mode 100644
index 00000000000..6ef4bdd4331
--- /dev/null
+++ b/tests/modeltests/custom_pk/tests.py
@@ -0,0 +1,183 @@
+# -*- coding: utf-8 -*-
+from django.conf import settings
+from django.db import DEFAULT_DB_ALIAS, transaction, IntegrityError
+from django.test import TestCase
+
+from models import Employee, Business, Bar, Foo
+
+
+class CustomPKTests(TestCase):
+    def test_custom_pk(self):
+        dan = Employee.objects.create(
+            employee_code=123, first_name="Dan", last_name="Jones"
+        )
+        self.assertQuerysetEqual(
+            Employee.objects.all(), [
+                "Dan Jones",
+            ],
+            unicode
+        )
+
+        fran = Employee.objects.create(
+            employee_code=456, first_name="Fran", last_name="Bones"
+        )
+        self.assertQuerysetEqual(
+            Employee.objects.all(), [
+                "Fran Bones",
+                "Dan Jones",
+            ],
+            unicode
+        )
+
+        self.assertEqual(Employee.objects.get(pk=123), dan)
+        self.assertEqual(Employee.objects.get(pk=456), fran)
+
+        self.assertRaises(Employee.DoesNotExist,
+            lambda: Employee.objects.get(pk=42)
+        )
+
+        # Use the name of the primary key, rather than pk.
+        self.assertEqual(Employee.objects.get(employee_code=123), dan)
+        # pk can be used as a substitute for the primary key.
+        self.assertQuerysetEqual(
+            Employee.objects.filter(pk__in=[123, 456]), [
+                "Fran Bones",
+                "Dan Jones",
+            ],
+            unicode
+        )
+        # The primary key can be accessed via the pk property on the model.
+        e = Employee.objects.get(pk=123)
+        self.assertEqual(e.pk, 123)
+        # Or we can use the real attribute name for the primary key:
+        self.assertEqual(e.employee_code, 123)
+
+        # Fran got married and changed her last name.
+        fran = Employee.objects.get(pk=456)
+        fran.last_name = "Jones"
+        fran.save()
+
+        self.assertQuerysetEqual(
+            Employee.objects.filter(last_name="Jones"), [
+                "Dan Jones",
+                "Fran Jones",
+            ],
+            unicode
+        )
+
+        emps = Employee.objects.in_bulk([123, 456])
+        self.assertEqual(emps[123], dan)
+
+        b = Business.objects.create(name="Sears")
+        b.employees.add(dan, fran)
+        self.assertQuerysetEqual(
+            b.employees.all(), [
+                "Dan Jones",
+                "Fran Jones",
+            ],
+            unicode
+        )
+        self.assertQuerysetEqual(
+            fran.business_set.all(), [
+                "Sears",
+            ],
+            lambda b: b.name
+        )
+
+        self.assertEqual(Business.objects.in_bulk(["Sears"]), {
+            "Sears": b,
+        })
+
+        self.assertQuerysetEqual(
+            Business.objects.filter(name="Sears"), [
+                "Sears"
+            ],
+            lambda b: b.name
+        )
+        self.assertQuerysetEqual(
+            Business.objects.filter(pk="Sears"), [
+                "Sears",
+            ],
+            lambda b: b.name
+        )
+
+        # Queries across tables, involving primary key
+        self.assertQuerysetEqual(
+            Employee.objects.filter(business__name="Sears"), [
+                "Dan Jones",
+                "Fran Jones",
+            ],
+            unicode,
+        )
+        self.assertQuerysetEqual(
+            Employee.objects.filter(business__pk="Sears"), [
+                "Dan Jones",
+                "Fran Jones",
+            ],
+            unicode,
+        )
+
+        self.assertQuerysetEqual(
+            Business.objects.filter(employees__employee_code=123), [
+                "Sears",
+            ],
+            lambda b: b.name
+        )
+        self.assertQuerysetEqual(
+            Business.objects.filter(employees__pk=123), [
+                "Sears",
+            ],
+            lambda b: b.name,
+        )
+
+        self.assertQuerysetEqual(
+            Business.objects.filter(employees__first_name__startswith="Fran"), [
+                "Sears",
+            ],
+            lambda b: b.name
+        )
+
+    def test_unicode_pk(self):
+        # Primary key may be unicode string
+        bus = Business.objects.create(name=u'jaźń')
+
+    def test_unique_pk(self):
+        # The primary key must also obviously be unique, so trying to create a
+        # new object with the same primary key will fail.
+        e = Employee.objects.create(
+            employee_code=123, first_name="Frank", last_name="Jones"
+        )
+        sid = transaction.savepoint()
+        self.assertRaises(IntegrityError,
+            Employee.objects.create, employee_code=123, first_name="Fred", last_name="Jones"
+        )
+        transaction.savepoint_rollback(sid)
+
+    def test_custom_field_pk(self):
+        # Regression for #10785 -- Custom fields can be used for primary keys.
+        new_bar = Bar.objects.create()
+        new_foo = Foo.objects.create(bar=new_bar)
+
+        # FIXME: This still doesn't work, but will require some changes in
+        # get_db_prep_lookup to fix it.
+        # f = Foo.objects.get(bar=new_bar.pk)
+        # self.assertEqual(f, new_foo)
+        # self.assertEqual(f.bar, new_bar)
+
+        f = Foo.objects.get(bar=new_bar)
+        self.assertEqual(f, new_foo),
+        self.assertEqual(f.bar, new_bar)
+
+
+    # SQLite lets objects be saved with an empty primary key, even though an
+    # integer is expected. So we can't check for an error being raised in that
+    # case for SQLite. Remove it from the suite for this next bit.
+    if settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'] != 'django.db.backends.sqlite3':
+        def test_required_pk(self):
+            # The primary key must be specified, so an error is raised if you
+            # try to create an object without it.
+            sid = transaction.savepoint()
+            self.assertRaises(IntegrityError,
+                Employee.objects.create, first_name="Tom", last_name="Smith"
+            )
+            transaction.savepoint_rollback(sid)