test: fix non-determinism in test-crypto-domains

The test implicitly assumed that crypto operations complete in the same
order as they are started but, because they go round-trip through the
thread pool, there is no such guarantee.  Enforce proper sequencing.

Fixes node-forward/node#22.

PR-URL: https://github.com/node-forward/node/pull/23
Reviewed-By: Fedor Indutny <fedor@indutny.com>

test/simple/test-crypto-domains.js

@@ -24,21 +24,37 @@ var domain = require('domain');
 var assert = require('assert');
 var d = domain.create();
 var expect = ['pbkdf2', 'randomBytes', 'pseudoRandomBytes']
+var errors = 0;
+
+process.on('exit', function() {
+  assert.equal(errors, 3);
+});
 
 d.on('error', function (e) {
   assert.equal(e.message, expect.shift());
+  errors += 1;
 });
 
 d.run(function () {
+  one();
+
+  function one() {
     crypto.pbkdf2('a', 'b', 1, 8, function () {
+      two();
       throw new Error('pbkdf2');
     });
+  }
 
+  function two() {
     crypto.randomBytes(4, function () {
+      three();
       throw new Error('randomBytes');
     });
+  }
 
+  function three() {
     crypto.pseudoRandomBytes(4, function () {
       throw new Error('pseudoRandomBytes');
     });
+  }
 });