diff --git a/src/testdir/test_increment.in b/src/testdir/test_increment.in
index ecbc6f9..2ae6b8a 100644
--- a/src/testdir/test_increment.in
+++ b/src/testdir/test_increment.in
@@ -277,7 +277,15 @@
  Expected:
  1) <Ctrl-a> and cursor is on a
  b
-   
+
+21) block-wise increment on part of hexadecimal
+Text:
+0x123456
+
+  Expected:
+  1) Ctrl-V f3 <ctrl-a>
+0x124456
+
 
 
 STARTTEST
@@ -401,6 +409,12 @@
 :.put =col('.')
 :set nrformats&vim
 
+:" Test 21
+:/^S21=/+,/^E21=/-y a
+:/^E21=/+put a
+:set nrformats&vim
+f3
+
 :" Save the report
 :/^# Test 1/,$w! test.out
 :qa!
@@ -594,6 +608,13 @@
 
 
 
+# Test 21
+S21====
+0x123456
+E21====
+
+
+
 
 ENDTEST