From bda0165514a582978c2da672b528562df78a2d1a Mon Sep 17 00:00:00 2001
From: ZyX <kp-pav@yandex.ru>
Date: Mon, 4 Apr 2016 04:53:07 +0300
Subject: eval/encode: Make sure that encoder can encode NULL variables

Adds two undocumented v: variables: _null_list and _null_dict because I do not
know a reproducible way to get such lists (though I think I heard about this)
and dictionaries (do not remember hearing about them). NULL strings are obtained
using $XXX_UNEXISTENT_VAR_XXX.

Fixes crash in json_encode($XXX_UNEXISTENT_VAR_XXX). Other added tests worked
fine before this commit.
---
 test/unit/eval/tricks_spec.lua | 43 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 test/unit/eval/tricks_spec.lua

(limited to 'test/unit/eval/tricks_spec.lua')

diff --git a/test/unit/eval/tricks_spec.lua b/test/unit/eval/tricks_spec.lua
new file mode 100644
index 0000000000..4c5184995c
--- /dev/null
+++ b/test/unit/eval/tricks_spec.lua
@@ -0,0 +1,43 @@
+local helpers = require('test.unit.helpers')
+
+local cimport = helpers.cimport
+local to_cstr = helpers.to_cstr
+local ffi = helpers.ffi
+local eq = helpers.eq
+
+local eval = cimport('./src/nvim/eval.h', './src/nvim/memory.h')
+
+local eval_expr = function(expr)
+  return ffi.gc(eval.eval_expr(to_cstr(expr), nil), function(tv)
+    eval.clear_tv(tv)
+    eval.xfree(tv)
+  end)
+end
+
+describe('NULL typval_T', function()
+  it('is produced by $XXX_UNEXISTENT_VAR_XXX', function()
+    -- Required for various tests which need to check whether typval_T with NULL
+    -- string works correctly. This test checks that unexistent environment
+    -- variable produces NULL string, not that some specific environment
+    -- variable does not exist. Last bit is left for the test writers.
+    local unexistent_env = 'XXX_UNEXISTENT_VAR_XXX'
+    while os.getenv(unexistent_env) ~= nil do
+      unexistent_env = unexistent_env .. '_XXX'
+    end
+    local rettv = eval_expr('$' .. unexistent_env)
+    eq(eval.VAR_STRING, rettv.v_type)
+    eq(nil, rettv.vval.v_string)
+  end)
+
+  it('is produced by v:_null_list', function()
+    local rettv = eval_expr('v:_null_list')
+    eq(eval.VAR_LIST, rettv.v_type)
+    eq(nil, rettv.vval.v_list)
+  end)
+
+  it('is produced by v:_null_dict', function()
+    local rettv = eval_expr('v:_null_dict')
+    eq(eval.VAR_DICT, rettv.v_type)
+    eq(nil, rettv.vval.v_dict)
+  end)
+end)
-- 
cgit