diff --git a/django/utils/datastructures.py b/django/utils/datastructures.py
index ffdc73f9222..ee156b11d01 100644
--- a/django/utils/datastructures.py
+++ b/django/utils/datastructures.py
@@ -60,7 +60,10 @@ class SortedDict(dict):
         if isinstance(data, dict):
             self.keyOrder = data.keys()
         else:
-            self.keyOrder = [key for key, value in data]
+            self.keyOrder = []
+            for key, value in data:
+                if key not in self.keyOrder:
+                    self.keyOrder.append(key)
 
     def __deepcopy__(self, memo):
         from copy import deepcopy
diff --git a/tests/regressiontests/utils/datastructures.py b/tests/regressiontests/utils/datastructures.py
new file mode 100644
index 00000000000..52bf81a9e00
--- /dev/null
+++ b/tests/regressiontests/utils/datastructures.py
@@ -0,0 +1,51 @@
+"""
+>>> from django.utils.datastructures import SortedDict
+
+>>> d = SortedDict()
+>>> d[7] = 'seven'
+>>> d[1] = 'one'
+>>> d[9] = 'nine'
+>>> d.keys()
+[7, 1, 9]
+>>> d.values()
+['seven', 'one', 'nine']
+>>> d.items()
+[(7, 'seven'), (1, 'one'), (9, 'nine')]
+
+# Overwriting an item keeps it's place.
+>>> d[1] = 'ONE'
+>>> d.values()
+['seven', 'ONE', 'nine']
+
+# New items go to the end.
+>>> d[0] = 'nil'
+>>> d.keys()
+[7, 1, 9, 0]
+
+# Deleting an item, then inserting the same key again will place it at the end.
+>>> del d[7]
+>>> d.keys()
+[1, 9, 0]
+>>> d[7] = 'lucky number 7'
+>>> d.keys()
+[1, 9, 0, 7]
+
+# Changing the keys won't do anything, it's only a copy of the keys dict.
+>>> k = d.keys()
+>>> k.remove(9)
+>>> d.keys()
+[1, 9, 0, 7]
+
+# Initialising a SortedDict with two keys will just take the first one. A real
+# dict will actually take the second value so we will too, but we'll keep the
+# ordering from the first key found.
+>>> tuples = ((2, 'two'), (1, 'one'), (2, 'second-two'))
+>>> d = SortedDict(tuples)
+>>> d.keys()
+[2, 1]
+>>> real_dict = dict(tuples)
+>>> real_dict.values()
+['one', 'second-two']
+>>> d.values()
+['second-two', 'one']
+"""
\ No newline at end of file
diff --git a/tests/regressiontests/utils/tests.py b/tests/regressiontests/utils/tests.py
index eb3a722888a..abcd7212d8d 100644
--- a/tests/regressiontests/utils/tests.py
+++ b/tests/regressiontests/utils/tests.py
@@ -6,7 +6,14 @@ from unittest import TestCase
 
 from django.utils import html, checksums
 
-from timesince import timesince_tests
+import timesince
+import datastructures
+
+# Extra tests
+__test__ = {
+    'timesince': timesince,
+    'datastructures': datastructures,
+}
 
 class TestUtilsHtml(TestCase):
 
@@ -142,10 +149,6 @@ class TestUtilsChecksums(TestCase):
         for value, output in items:
             self.check_output(f, value, output)
 
-__test__ = {
-    'timesince_tests': timesince_tests,
-}
-
 if __name__ == "__main__":
     import doctest
     doctest.testmod()
diff --git a/tests/regressiontests/utils/timesince.py b/tests/regressiontests/utils/timesince.py
index 30200be6e9e..4f304ec7f7e 100644
--- a/tests/regressiontests/utils/timesince.py
+++ b/tests/regressiontests/utils/timesince.py
@@ -1,4 +1,4 @@
-timesince_tests = """
+"""
 >>> from datetime import datetime, timedelta
 >>> from django.utils.timesince import timesince