2 files changed, 37 insertions, 5 deletions
diff --git a/test/functional/helpers.lua b/test/functional/helpers.lua
index bf6e3dd38a..6c3f5190c9 100644
--- a/test/functional/helpers.lua
+++ b/test/functional/helpers.lua
@@ -25,7 +25,7 @@ if os.getenv('VALGRIND') then
   nvim_argv = valgrind_argv
 end
 
-local session, loop_running, last_error
+local session, loop_running, loop_stopped, last_error
 
 local function request(method, ...)
   local status, rv = session:request(method, ...)
@@ -39,7 +39,11 @@ local function request(method, ...)
   end
   -- Make sure this will only return after all buffered characters have been
   -- processed
-  session:request('vim_eval', '1')
+  if not loop_stopped then
+    -- Except when the loop has been stopped by a notification triggered
+    -- by the initial request, for example.
+    session:request('vim_eval', '1')
+  end
   return rv
 end
 
@@ -71,6 +75,7 @@ local function run(request_cb, notification_cb, setup_cb)
     call_and_stop_on_error(setup_cb)
   end
 
+  loop_stopped = false
   loop_running = true
   session:run(on_request, on_notification, on_setup)
   loop_running = false
@@ -82,6 +87,7 @@ local function run(request_cb, notification_cb, setup_cb)
 end
 
 local function stop()
+  loop_stopped = true
   session:stop()
 end
 
diff --git a/test/functional/shell/viml_system_spec.lua b/test/functional/shell/viml_system_spec.lua
index a8bab8e26e..91e115aedf 100644
--- a/test/functional/shell/viml_system_spec.lua
+++ b/test/functional/shell/viml_system_spec.lua
@@ -3,8 +3,8 @@
 -- - `systemlist()`
 
 local helpers = require('test.functional.helpers')
-local eq, clear, eval, feed =
-  helpers.eq, helpers.clear, helpers.eval, helpers.feed
+local eq, clear, eval, feed, nvim =
+  helpers.eq, helpers.clear, helpers.eval, helpers.feed, helpers.nvim
 
 
 local function create_file_with_nuls(name)
@@ -55,6 +55,21 @@ describe('system()', function()
     end)
   end)
 
+  describe('passing a lot of input', function()
+    it('returns the program output', function()
+      local input = {}
+      -- write more than 1mb of data, which should be enough to overcome
+      -- the os buffer limit and force multiple event loop iterations to write
+      -- everything
+      for i = 1, 0xffff do
+        input[#input + 1] = '01234567890ABCDEFabcdef'
+      end
+      input = table.concat(input, '\n')
+      nvim('set_var', 'input', input)
+      eq(input, eval('system("cat -", g:input)'))
+    end)
+  end)
+
   describe('passing number as input', function()
     it('stringifies the input', function()
       eq('1', eval('system("cat", 1)'))
@@ -129,6 +144,17 @@ describe('systemlist()', function()
     end)
   end)
 
+  describe('passing a lot of input', function()
+    it('returns the program output', function()
+      local input = {}
+      for i = 1, 0xffff do
+        input[#input + 1] = '01234567890ABCDEFabcdef'
+      end
+      nvim('set_var', 'input', input)
+      eq(input, eval('systemlist("cat -", g:input)'))
+    end)
+  end)
+
   describe('with output containing NULs', function()
     local fname = 'Xtest'
 
@@ -166,7 +192,7 @@ describe('systemlist()', function()
   if xclip then
     describe("with a program that doesn't close stdout", function()
       it('will exit properly after passing input', function()
-        eq(nil, eval(
+        eq({}, eval(
           "systemlist('xclip -i -selection clipboard', ['clip', 'data'])"))
         eq({'clip', 'data'}, eval(
           "systemlist('xclip -o -selection clipboard')"))