diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index 67163e6..2f2b559 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -203,8 +203,7 @@
   let start = reltime()
   call assert_equal(v:none, ch_read(handle, {'timeout': 333}))
   let elapsed = reltime(start)
-  call assert_true(reltimefloat(elapsed) > 0.3)
-  call assert_true(reltimefloat(elapsed) < 0.6)
+  call assert_inrange(0.3, 0.6, reltimefloat(reltime(start)))
 
   " Send without waiting for a response, then wait for a response.
   call ch_sendexpr(handle, 'wait a bit')
@@ -434,9 +433,7 @@
     else
       " Failed connection should wait about 500 msec.  Can be longer if the
       " computer is busy with other things.
-      let elapsed = reltime(start)
-      call assert_true(reltimefloat(elapsed) > 0.3)
-      call assert_true(reltimefloat(elapsed) < 1.5)
+      call assert_inrange(0.3, 1.5, reltimefloat(reltime(start)))
     endif
   catch
     if v:exception !~ 'Connection reset by peer'
@@ -1590,8 +1587,7 @@
   else
     let elapsed = 1.0
   endif
-  call assert_true(elapsed > 0.5)
-  call assert_true(elapsed < 1.0)
+  call assert_inrange(0.5, 1.0, elapsed)
 endfunc
 
 """""""""
@@ -1764,10 +1760,6 @@
   bwipe!
 endfunc
 
-func MyLineCountCb(ch, msg)
-  let g:linecount += 1
-endfunc
-
 func Test_read_nonl_line()
   if !has('job')
     return
@@ -1775,8 +1767,28 @@
 
   let g:linecount = 0
   let arg = 'import sys;sys.stdout.write("1\n2\n3")'
-  call job_start([s:python, '-c', arg], {'callback': 'MyLineCountCb'})
+  call job_start([s:python, '-c', arg], {'callback': {-> execute('let g:linecount += 1')}})
   call WaitForAssert({-> assert_equal(3, g:linecount)})
+  unlet g:linecount
+endfunc
+
+func Test_read_nonl_in_close_cb()
+  if !has('job')
+    return
+  endif
+
+  func s:close_cb(ch)
+    while ch_status(a:ch) == 'buffered'
+      let g:out .= ch_read(a:ch)
+    endwhile
+  endfunc
+
+  let g:out = ''
+  let arg = 'import sys;sys.stdout.write("1\n2\n3")'
+  call job_start([s:python, '-c', arg], {'close_cb': function('s:close_cb')})
+  call WaitForAssert({-> assert_equal('123', g:out)})
+  unlet g:out
+  delfunc s:close_cb
 endfunc
 
 func Test_read_from_terminated_job()
@@ -1786,8 +1798,9 @@
 
   let g:linecount = 0
   let arg = 'import os,sys;os.close(1);sys.stderr.write("test\n")'
-  call job_start([s:python, '-c', arg], {'callback': 'MyLineCountCb'})
+  call job_start([s:python, '-c', arg], {'callback': {-> execute('let g:linecount += 1')}})
   call WaitForAssert({-> assert_equal(1, g:linecount)})
+  unlet g:linecount
 endfunc
 
 func Test_job_start_windows()