4 files changed, 32 insertions, 0 deletions
diff --git a/test/functional/api/buffer_spec.lua b/test/functional/api/buffer_spec.lua
index 075504fc8c..e58ae440cf 100644
--- a/test/functional/api/buffer_spec.lua
+++ b/test/functional/api/buffer_spec.lua
@@ -6,6 +6,8 @@ local funcs = helpers.funcs
 local request = helpers.request
 local neq = helpers.neq
 local NIL = helpers.NIL
+local meth_pcall = helpers.meth_pcall
+local command = helpers.command
 
 describe('api/buf', function()
   before_each(clear)
@@ -251,6 +253,15 @@ describe('api/buf', function()
       eq(1, funcs.exists('b:lua'))
       curbufmeths.del_var('lua')
       eq(0, funcs.exists('b:lua'))
+      eq({false, 'Key "lua" doesn\'t exist'}, meth_pcall(curbufmeths.del_var, 'lua'))
+      curbufmeths.set_var('lua', 1)
+      command('lockvar b:lua')
+      eq({false, 'Key is locked: lua'}, meth_pcall(curbufmeths.del_var, 'lua'))
+      eq({false, 'Key is locked: lua'}, meth_pcall(curbufmeths.set_var, 'lua', 1))
+      eq({false, 'Key is read-only: changedtick'},
+         meth_pcall(curbufmeths.del_var, 'changedtick'))
+      eq({false, 'Key is read-only: changedtick'},
+         meth_pcall(curbufmeths.set_var, 'changedtick', 1))
     end)
   end)
 
diff --git a/test/functional/api/tabpage_spec.lua b/test/functional/api/tabpage_spec.lua
index e10f30085f..d7ef53a88f 100644
--- a/test/functional/api/tabpage_spec.lua
+++ b/test/functional/api/tabpage_spec.lua
@@ -6,6 +6,8 @@ local curtabmeths = helpers.curtabmeths
 local funcs = helpers.funcs
 local request = helpers.request
 local NIL = helpers.NIL
+local meth_pcall = helpers.meth_pcall
+local command = helpers.command
 
 describe('api/tabpage', function()
   before_each(clear)
@@ -32,6 +34,11 @@ describe('api/tabpage', function()
       eq(1, funcs.exists('t:lua'))
       curtabmeths.del_var('lua')
       eq(0, funcs.exists('t:lua'))
+      eq({false, 'Key "lua" doesn\'t exist'}, meth_pcall(curtabmeths.del_var, 'lua'))
+      curtabmeths.set_var('lua', 1)
+      command('lockvar t:lua')
+      eq({false, 'Key is locked: lua'}, meth_pcall(curtabmeths.del_var, 'lua'))
+      eq({false, 'Key is locked: lua'}, meth_pcall(curtabmeths.set_var, 'lua', 1))
     end)
 
     it('tabpage_set_var returns the old value', function()
diff --git a/test/functional/api/vim_spec.lua b/test/functional/api/vim_spec.lua
index 551f408c57..3348368a36 100644
--- a/test/functional/api/vim_spec.lua
+++ b/test/functional/api/vim_spec.lua
@@ -7,6 +7,8 @@ local os_name = helpers.os_name
 local meths = helpers.meths
 local funcs = helpers.funcs
 local request = helpers.request
+local meth_pcall = helpers.meth_pcall
+local command = helpers.command
 
 describe('api', function()
   before_each(clear)
@@ -117,6 +119,11 @@ describe('api', function()
       eq(1, funcs.exists('g:lua'))
       meths.del_var('lua')
       eq(0, funcs.exists('g:lua'))
+      eq({false, 'Key "lua" doesn\'t exist'}, meth_pcall(meths.del_var, 'lua'))
+      meths.set_var('lua', 1)
+      command('lockvar lua')
+      eq({false, 'Key is locked: lua'}, meth_pcall(meths.del_var, 'lua'))
+      eq({false, 'Key is locked: lua'}, meth_pcall(meths.set_var, 'lua', 1))
     end)
 
     it('vim_set_var returns the old value', function()
diff --git a/test/functional/api/window_spec.lua b/test/functional/api/window_spec.lua
index 465bda6bc9..deffc68994 100644
--- a/test/functional/api/window_spec.lua
+++ b/test/functional/api/window_spec.lua
@@ -8,6 +8,8 @@ local curwinmeths = helpers.curwinmeths
 local funcs = helpers.funcs
 local request = helpers.request
 local NIL = helpers.NIL
+local meth_pcall = helpers.meth_pcall
+local command = helpers.command
 
 -- check if str is visible at the beginning of some line
 local function is_visible(str)
@@ -137,6 +139,11 @@ describe('api/win', function()
       eq(1, funcs.exists('w:lua'))
       curwinmeths.del_var('lua')
       eq(0, funcs.exists('w:lua'))
+      eq({false, 'Key "lua" doesn\'t exist'}, meth_pcall(curwinmeths.del_var, 'lua'))
+      curwinmeths.set_var('lua', 1)
+      command('lockvar w:lua')
+      eq({false, 'Key is locked: lua'}, meth_pcall(curwinmeths.del_var, 'lua'))
+      eq({false, 'Key is locked: lua'}, meth_pcall(curwinmeths.set_var, 'lua', 1))
     end)
 
     it('window_set_var returns the old value', function()