diff --git a/src/testdir/test_startup.vim b/src/testdir/test_startup.vim
index 17ac94d..ae12f61 100644
--- a/src/testdir/test_startup.vim
+++ b/src/testdir/test_startup.vim
@@ -1121,6 +1121,21 @@
   endif
 endfunc
 
+" Test for the "-D" (debugger) argument
+func Test_D_arg()
+  CheckRunVimInTerminal
+
+  let cmd = GetVimCommandCleanTerm() .. ' -D'
+  let buf = term_start(cmd, {'term_rows' : 10})
+  call WaitForAssert({-> assert_equal("running", term_getstatus(buf))})
+
+  call WaitForAssert({-> assert_equal('Entering Debug mode.  Type "cont" to continue.',
+  \                  term_getline(buf, 7))})
+  call WaitForAssert({-> assert_equal('>', term_getline(buf, 10))})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 " Test for too many edit argument errors
 func Test_too_many_edit_args()
   " Can't catch the output of gvim.