datastore: clean up tests

https://github.com/GoogleCloudPlatform/gcloud-node/pull/316\#discussion_r21727802

regression/datastore.js

@@ -21,6 +21,7 @@
 var env = require('./env.js');
 
 var assert = require('assert');
+var async = require('async');
 var datastore = require('../lib/datastore');
 var ds = datastore.dataset(env);
 var entity = require('../lib/datastore/entity.js');
@@ -431,16 +432,11 @@ describe('datastore', function() {
       };
 
       ds.runInTransaction(function(t, tDone) {
-        t.get(key, function(err, entity) {
+        t.get(key, function(err) {
           assert.ifError(err);
 
-          if (entity) {
-            tDone();
-            return;
-          } else {
-            t.save({ key: key, data: obj });
-            tDone();
-          }
+          t.save({ key: key, data: obj });
+          tDone();
         });
       }, function(err) {
         assert.ifError(err);
@@ -456,11 +452,12 @@ describe('datastore', function() {
     });
 
     it('should commit all saves and deletes at the end', function(done) {
-      var incompleteKey = ds.key('Company');
+      var deleteKey = ds.key(['Company', 'Subway']);
       var key = ds.key(['Company', 'Google']);
+      var incompleteKey = ds.key('Company');
 
       ds.runInTransaction(function(t, tDone) {
-        t.delete(key);
+        t.delete(deleteKey);
 
         t.save([
           {
@@ -477,15 +474,28 @@ describe('datastore', function() {
       }, function(err) {
         assert.ifError(err);
 
-        // Should return a populated result because the last operation wins.
-        ds.get(key, function(err, entity) {
-          assert.ifError(err);
-          assert.equal(typeof entity, 'object');
+        // Incomplete key should have been given an ID.
+        assert.equal(incompleteKey.path.length, 2);
+
+        async.parallel([
+          // The key queued for deletion should have been deleted.
+          function(done) {
+            ds.get(deleteKey, function(err, entity) {
+              assert.ifError(err);
+              assert.equal(typeof entity, 'undefined');
+              done();
+            });
+          },
 
-          // Incomplete key should have been given an id.
-          assert.equal(incompleteKey.path.length, 2);
-          done();
-        });
+          // Data should have been updated on the key.
+          function(done) {
+            ds.get(key, function(err, entity) {
+              assert.ifError(err);
+              assert.equal(entity.data.rating, 10);
+              done();
+            });
+          }
+        ], done);
       });
     });