edited challenge notebook and added tests

arrays_strings/group_items/test_group_ordered.py

@@ -0,0 +1,20 @@
+from nose.tools import assert_equal
+
+class TestFoo(object):
+
+    def test_foo(self):
+        assert_equal(group_ordered(None), None)
+        assert_equal(group_ordered([]), [])
+        assert_equal(group_ordered([1]), [1])
+        assert_equal(group_ordered([1,2,1,3,2]),[1,1,2,2,3])
+        assert_equal(group_ordered(['a','b','a']),['a','a','b'])
+        assert_equal(group_ordered([1,1,2,3,4,5,2,1]),[1,1,1,2,2,3,4,5])
+        assert_equal(group_ordered([1,2,3,4,3,4]),[1,2,3,3,4,4])
+        print('Success: test_foo')
+
+def main():
+    test = TestFoo()
+    test.test_foo()
+
+if __name__ == '__main__':
+    main()