diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index a819961..e76c524 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -69,6 +69,13 @@
   endif
 endfunc
 
+let s:responseHandle = -1
+let s:responseMsg = ''
+func s:RequestHandler(handle, msg)
+  let s:responseHandle = a:handle
+  let s:responseMsg = a:msg
+endfunc
+
 func Test_communicate()
   let handle = s:start_server()
   if handle < 0
@@ -86,6 +93,12 @@
   call assert_equal('added1', getline(line('$') - 1))
   call assert_equal('added2', getline('$'))
 
+  " Send a request with a specific handler.
+  call ch_sendexpr(handle, 'hello!', 's:RequestHandler')
+  sleep 10m
+  call assert_equal(handle, s:responseHandle)
+  call assert_equal('got it', s:responseMsg)
+
   " Send an eval request that works.
   call assert_equal('ok', ch_sendexpr(handle, 'eval-works'))
   sleep 10m