diff --git a/src/testdir/test_termdebug.vim b/src/testdir/test_termdebug.vim
index 23ec0e8..3b2b8c1 100644
--- a/src/testdir/test_termdebug.vim
+++ b/src/testdir/test_termdebug.vim
@@ -80,6 +80,34 @@
         \  'priority': 110, 'group': 'TermDebug'}],
         \ sign_getplaced('', #{group: 'TermDebug'})[0].signs)})
   Continue
+
+  let cn = 0
+  " 60 is approx spaceBuffer * 3
+  if winwidth(0) <= 78 + 60
+    Var
+    call assert_equal(winnr(), winnr('$'))
+    call assert_equal(winlayout(), ['col', [['leaf', 1002], ['leaf', 1001], ['leaf', 1000], ['leaf', 1003 + cn]]])
+    let cn += 1
+    bw!
+    Asm
+    call assert_equal(winnr(), winnr('$'))
+    call assert_equal(winlayout(), ['col', [['leaf', 1002], ['leaf', 1001], ['leaf', 1000], ['leaf', 1003 + cn]]])
+    let cn += 1
+    bw!
+  endif
+  set columns=160
+  Var
+  call assert_equal(winnr(), winnr('$') - 1)
+  call assert_equal(winlayout(), ['col', [['leaf', 1002], ['leaf', 1001], ['row', [['leaf', 1003 + cn], ['leaf', 1000]]]]])
+  let cn += 1
+  bw!
+  Asm
+  call assert_equal(winnr(), winnr('$') - 1)
+  call assert_equal(winlayout(), ['col', [['leaf', 1002], ['leaf', 1001], ['row', [['leaf', 1003 + cn], ['leaf', 1000]]]]])
+  let cn += 1
+  bw!
+  set columns&
+
   wincmd t
   quit!
   redraw!