diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index 15ca9dd..e7fcf95 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -1980,3 +1980,21 @@
   unlet! g:val
   unlet! g:job
 endfunc
+
+func Test_raw_large_data()
+  try
+    let g:out = ''
+    let job = job_start(s:python . " test_channel_pipe.py",
+	  \ {'mode': 'raw', 'drop': 'never', 'noblock': 1,
+      \  'callback': {ch, msg -> execute('let g:out .= msg')}})
+
+    let want = repeat('X', 79999) . "\n"
+    call ch_sendraw(job, want)
+    let g:Ch_job = job
+    call WaitForAssert({-> assert_equal("dead", job_status(g:Ch_job))})
+    call assert_equal(want, substitute(g:out, '\r', '', 'g'))
+  finally
+    call job_stop(job)
+    unlet g:out
+  endtry
+endfunc
diff --git a/src/testdir/test_channel_pipe.py b/src/testdir/test_channel_pipe.py
index 9403786..810a8e3 100644
--- a/src/testdir/test_channel_pipe.py
+++ b/src/testdir/test_channel_pipe.py
@@ -56,4 +56,8 @@
         if typed.startswith("doubleerr "):
             print(typed[10:-1] + "\nAND " + typed[10:-1], file=sys.stderr)
             sys.stderr.flush()
+        if typed.startswith("XXX"):
+            print(typed, end='')
+            sys.stderr.flush()
+            break