Add test for setpgid

Author: grncdr

test/unit/test-setpgid.js

@@ -0,0 +1,20 @@
+var assert = require('assert'),
+    posix = require("../../lib/posix");
+
+assert.throws(function () {
+  posix.setpgid()
+}, /exactly two arguments/)
+
+assert.throws(function () {
+  posix.setpgid('a', 1)
+}, /must be an integer/)
+
+assert.throws(function () {
+  posix.setpgid(1, 'a')
+}, /must be an integer/)
+
+var old = posix.getpgid(0);
+assert.ok(old !== process.id);
+
+posix.setpgid(0, process.pid);
+assert.equal(posix.getpgid(0), process.pid);