patch 7.4.1902
Problem:    No test for collapsing buffers for a channel.  Some text is lost.
Solution:   Add a simple test.  Set rq_buflen correctly.
diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index a60147b..d65e528 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -538,6 +538,9 @@
     call assert_equal("this", ch_readraw(handle))
     call assert_equal("AND this", ch_readraw(handle))
 
+    call ch_sendraw(handle, "split this line\n")
+    call assert_equal("this linethis linethis line", ch_readraw(handle))
+
     let reply = ch_evalraw(handle, "quit\n")
     call assert_equal("Goodbye!", reply)
   finally