Can now run tests that use composite_primary_keys in the fixtures. Adding a new test to check that you can't add duplicate user preferences, and the display name of the user is guaranteed to be unique.

test/unit/user_preference_test.rb

@@ -1,8 +1,26 @@
 require File.dirname(__FILE__) + '/../test_helper'
 
 class UserPreferenceTest < ActiveSupport::TestCase
-  # Replace this with your real tests.
-  def test_truth
-    assert true
+  fixtures :users, :user_preferences
+
+  # This checks to make sure that there are two user preferences
+  # stored in the test database.
+  # This test needs to be updated for every addition/deletion from
+  # the fixture file
+  def test_check_count
+    assert_equal 2, UserPreference.count
   end
+
+  # Checks that you cannot add a new preference, that is a duplicate
+  def test_add_duplicate_preference
+    up = user_preferences(:a)
+    newUP = UserPreference.new
+    newUP.user = users(:normal_user)
+    newUP.k = up.k
+    newUP.v = "some other value"
+    assert_not_equal newUP.v, up.v
+    assert_raise (ActiveRecord::StatementInvalid) {newUP.save}
+  end
+  
+
 end