diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3177b9d..168b49d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,10 @@
 Changelog
 =========
 
-0.5.4
------
+0.5.4-pre
+---------
+
+ - Refectoring of Analysis modules
 
 0.5.3
 -----
diff --git a/README.md b/README.md
index 62f48ce..baf7b4b 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,8 @@ Latest Changes
 
 ### Changes in 0.5.4-pre
 
+ - Refactoring of Analysis modules
+
 ### Changes in 0.5.3
 
  - Python 3.10 compatability fixes
diff --git a/test/test_sitools.py b/test/test_sitools.py
index 06c8b59..dec3e45 100644
--- a/test/test_sitools.py
+++ b/test/test_sitools.py
@@ -17,7 +17,7 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import unittest
-from math import inf
+from math import inf, nan
 from decimal import Decimal  # Needed for test_representation()
 
 # Import targets to be tested
@@ -81,6 +81,7 @@ class TestTSIToolsValue(unittest.TestCase):
         self.assertEqual(str(Value(1e24)), "1.00000Y")
         self.assertEqual(str(Value(1e27)), "\N{INFINITY}")
         self.assertEqual(str(Value(-1e27)), "-\N{INFINITY}")
+        self.assertEqual(str(Value(nan)), "NaN")
         self.assertEqual(float(Value(1e27)), 1e27)
         self.assertEqual(
             str(Value(11, fmt=Format(printable_max=10))), '')