diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index 9529b76..4bac4f9 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -1124,6 +1124,24 @@
   quit
 endfunc
 
+func Test_terminal_dumpdiff_swap()
+  call assert_equal(1, winnr('$'))
+  call term_dumpdiff('dumps/Test_popup_command_01.dump', 'dumps/Test_popup_command_03.dump')
+  call assert_equal(2, winnr('$'))
+  call assert_equal(62, line('$'))
+  call assert_match('Test_popup_command_01.dump', getline(21))
+  call assert_match('Test_popup_command_03.dump', getline(42))
+  call assert_match('Undo', getline(3))
+  call assert_match('three four five', getline(45))
+
+  normal s
+  call assert_match('Test_popup_command_03.dump', getline(21))
+  call assert_match('Test_popup_command_01.dump', getline(42))
+  call assert_match('three four five', getline(3))
+  call assert_match('Undo', getline(45))
+  quit
+endfunc
+
 func Test_terminal_dumpdiff_options()
   set laststatus=0
   call assert_equal(1, winnr('$'))