test: Use lua to perform sanity API checks

Sanity API checks made by the python-client in the api-python travis target were
converted to lua and will now live in this repository. This will simplify
performing breaking changes to the API as it won't be necessary to send parallel
PRs the python-client.

test/functional/api/vim_spec.lua

@@ -0,0 +1,108 @@
+-- Sanity checks for vim_* API calls via msgpack-rpc
+local helpers = require('test.functional.helpers')
+local clear, nvim, eq, ok = helpers.clear, helpers.nvim, helpers.eq, helpers.ok
+
+
+describe('vim_* functions', function()
+  before_each(clear)
+
+  describe('command', function()
+    it('works', function()
+      local fname = os.tmpname()
+      nvim('command', 'new')
+      nvim('command', 'edit '..fname)
+      nvim('command', 'normal itesting\napi')
+      nvim('command', 'w')
+      local f = io.open(fname)
+      ok(f ~= nil)
+      eq('testing\napi\n', f:read('*a'))
+      f:close()
+      os.remove(fname)
+    end)
+  end)
+
+  describe('eval', function()
+    it('works', function()
+      nvim('command', 'let g:v1 = "a"')
+      nvim('command', 'let g:v2 = [1, 2, {"v3": 3}]')
+      eq({v1 = 'a', v2 = {1, 2, {v3 = 3}}}, nvim('eval', 'g:'))
+    end)
+  end)
+
+  describe('strwidth', function()
+    it('works', function()
+      eq(3, nvim('strwidth', 'abc'))
+      -- 6 + (neovim)
+      -- 19 * 2 (each japanese character occupies two cells)
+      eq(44, nvim('strwidth', 'neovimのデザインかなりまともなのになってる。'))
+    end)
+  end)
+
+  describe('{get,set}_current_line', function()
+    it('works', function()
+      eq('', nvim('get_current_line'))
+      nvim('set_current_line', 'abc')
+      eq('abc', nvim('get_current_line'))
+    end)
+  end)
+
+  describe('{get,set}_var', function()
+    it('works', function()
+      nvim('set_var', 'lua', {1, 2, {['3'] = 1}})
+      eq({1, 2, {['3'] = 1}}, nvim('get_var', 'lua'))
+      eq({1, 2, {['3'] = 1}}, nvim('eval', 'g:lua'))
+    end)
+  end)
+
+  describe('{get,set}_option', function()
+    it('works', function()
+      ok(nvim('get_option', 'equalalways'))
+      nvim('set_option', 'equalalways', false)
+      ok(not nvim('get_option', 'equalalways'))
+    end)
+  end)
+
+  describe('{get,set}_current_buffer and get_buffers', function()
+    it('works', function()
+      eq(1, #nvim('get_buffers'))
+      eq(nvim('get_buffers')[1], nvim('get_current_buffer'))
+      nvim('command', 'new')
+      eq(2, #nvim('get_buffers'))
+      eq(nvim('get_buffers')[2], nvim('get_current_buffer'))
+      nvim('set_current_buffer', nvim('get_buffers')[1])
+      eq(nvim('get_buffers')[1], nvim('get_current_buffer'))
+    end)
+  end)
+
+  describe('{get,set}_current_window and get_windows', function()
+    it('works', function()
+      eq(1, #nvim('get_windows'))
+      eq(nvim('get_windows')[1], nvim('get_current_window'))
+      nvim('command', 'vsplit')
+      nvim('command', 'split')
+      eq(3, #nvim('get_windows'))
+      eq(nvim('get_windows')[1], nvim('get_current_window'))
+      nvim('set_current_window', nvim('get_windows')[2])
+      eq(nvim('get_windows')[2], nvim('get_current_window'))
+    end)
+  end)
+
+  describe('{get,set}_current_tabpage and get_tabpages', function()
+    it('works', function()
+      eq(1, #nvim('get_tabpages'))
+      eq(nvim('get_tabpages')[1], nvim('get_current_tabpage'))
+      nvim('command', 'tabnew')
+      eq(2, #nvim('get_tabpages'))
+      eq(2, #nvim('get_windows'))
+      eq(nvim('get_windows')[2], nvim('get_current_window'))
+      eq(nvim('get_tabpages')[2], nvim('get_current_tabpage'))
+      nvim('set_current_window', nvim('get_windows')[1])
+      -- Switching window also switches tabpages if necessary
+      eq(nvim('get_tabpages')[1], nvim('get_current_tabpage'))
+      eq(nvim('get_windows')[1], nvim('get_current_window'))
+      nvim('set_current_tabpage', nvim('get_tabpages')[2])
+      eq(nvim('get_tabpages')[2], nvim('get_current_tabpage'))
+      eq(nvim('get_windows')[2], nvim('get_current_window'))
+    end)
+  end)
+end)