Index: tests/natools-smaz-tests.adb
==================================================================
--- tests/natools-smaz-tests.adb
+++ tests/natools-smaz-tests.adb
@@ -186,10 +186,14 @@
            48, 243, 152, 0, 255, 7, 49, 48, 32, 50, 48, 32, 51,
            48, 161, 45, 60, 33, 166, 0, 231, 71, 151, 3, 3, 87));
       Roundtrip_Test (Test, Original.Dictionary,
          ": : : :",
          (255, 6, 58, 32, 58, 32, 58, 32, 58));
+      Roundtrip_Test (Test, Original.Dictionary,
+         (1 .. 300 => ':'),
+         (1 .. 2 => 255, 3 .. 258 => 58,
+           259 => 255, 260 => 43, 261 .. 304 => 58));
    exception
       when Error : others => Test.Report_Exception (Error);
    end Sample_Strings;