ci: nodejs client acceptance-test #7706

ci: install nodejs 8 in Appveyor, Travis

provider: check node version for debug support
Resolve https://github.com/neovim/neovim/pull/7577#issuecomment-350590592 for Unix.

provider: test if nodejs in ci supports --inspect-brk

nodejs host for neovim requires nodejs 6+ to work properly.
nodejs 6.12+ or 7.6+ is required for debug support via `node --inspect-brk`.

provider: run cli.js of nodejs host directly

npm shims are useless because the user cannot set node to debug mode via
--inspect-brk. This is problematic on Windows which use batchfiles and
shell scripts to compensate for not supporting shebang.

The patch uses `npm root -g` to get the absolute path of the global npm
modules. If that fails, then the user did not install neovim npm package
globally. Use that absolute path to find `neovim/bin/cli.js`, which is
what the npm shim actually runs with node. glob() is for a simple file
check in case bin/ is removed because the npm shims are ignored now.

test/functional/provider/nodejs_spec.lua

@@ -0,0 +1,70 @@
+local helpers = require('test.functional.helpers')(after_each)
+local eq, clear = helpers.eq, helpers.clear
+local missing_provider = helpers.missing_provider
+local command = helpers.command
+local write_file = helpers.write_file
+local eval = helpers.eval
+local sleep = helpers.sleep
+local funcs = helpers.funcs
+local retry = helpers.retry
+
+do
+  clear()
+  if missing_provider('node') then
+    pending(
+      "Cannot find the neovim nodejs host. Try :checkhealth",
+      function() end)
+    return
+  end
+end
+
+before_each(function()
+  clear()
+end)
+
+describe('nodejs', function()
+  it('can inspect', function()
+    eq(1, funcs['provider#node#can_inspect']())
+  end)
+end)
+
+describe('nodejs host', function()
+  teardown(function ()
+    os.remove('Xtest-nodejs-hello.js')
+    os.remove('Xtest-nodejs-hello-plugin.js')
+  end)
+
+  it('works', function()
+    local fname = 'Xtest-nodejs-hello.js'
+    write_file(fname, [[
+      const socket = process.env.NVIM_LISTEN_ADDRESS;
+      const neovim = require('neovim');
+      const nvim = neovim.attach({socket: socket});
+      nvim.command('let g:job_out = "hello"');
+      nvim.command('call jobstop(g:job_id)');
+    ]])
+    command('let g:job_id = jobstart(["node", "'..fname..'"])')
+    retry(nil, 1000, function() eq('hello', eval('g:job_out')) end)
+  end)
+  it('plugin works', function()
+    local fname = 'Xtest-nodejs-hello-plugin.js'
+    write_file(fname, [[
+      const socket = process.env.NVIM_LISTEN_ADDRESS;
+      const neovim = require('neovim');
+      const nvim = neovim.attach({socket: socket});
+
+      class TestPlugin {
+          hello() {
+              this.nvim.command('let g:job_out = "hello-plugin"')
+          }
+      }
+
+      const PluginClass = neovim.Plugin(TestPlugin);
+      const plugin = new PluginClass(nvim);
+      plugin.hello();
+      nvim.command('call jobstop(g:job_id)');
+    ]])
+    command('let g:job_id = jobstart(["node", "'..fname..'"])')
+    retry(nil, 1000, function() eq('hello-plugin', eval('g:job_out')) end)
+  end)
+end)