API: nvim_get_proc_children()

ref https://github.com/libuv/libuv/pull/836

test/functional/api/proc_spec.lua

@@ -0,0 +1,53 @@
+local helpers = require('test.functional.helpers')(after_each)
+
+local clear, eq = helpers.clear, helpers.eq
+local funcs = helpers.funcs
+local nvim_argv = helpers.nvim_argv
+local request = helpers.request
+local retry = helpers.retry
+
+describe('api', function()
+  before_each(clear)
+
+  describe('nvim_get_proc_children', function()
+    it('returns child process ids', function()
+      local this_pid = funcs.getpid()
+
+      local job1 = funcs.jobstart(nvim_argv)
+      retry(nil, nil, function()
+        eq(1, #request('nvim_get_proc_children', this_pid))
+      end)
+
+      local job2 = funcs.jobstart(nvim_argv)
+      retry(nil, nil, function()
+        eq(2, #request('nvim_get_proc_children', this_pid))
+      end)
+
+      funcs.jobstop(job1)
+      retry(nil, nil, function()
+        eq(1, #request('nvim_get_proc_children', this_pid))
+      end)
+
+      funcs.jobstop(job2)
+      retry(nil, nil, function()
+        eq(0, #request('nvim_get_proc_children', this_pid))
+      end)
+    end)
+
+    it('validates input', function()
+      local status, rv = pcall(request, "nvim_get_proc_children", -1)
+      eq(false, status)
+      eq("Invalid pid: -1", string.match(rv, "Invalid.*"))
+
+      status, rv = pcall(request, "nvim_get_proc_children", 0)
+      eq(false, status)
+      eq("Invalid pid: 0", string.match(rv, "Invalid.*"))
+
+      -- Assume PID 99999999 does not exist.
+      status, rv = pcall(request, "nvim_get_proc_children", 99999999)
+      eq(true, status)
+      eq({}, rv)
+    end)
+  end)
+
+end)