diff --git a/lib/datastore/request.js b/lib/datastore/request.js
index e47e3ff9396..50ab4d39964 100644
--- a/lib/datastore/request.js
+++ b/lib/datastore/request.js
@@ -106,14 +106,10 @@ DatastoreRequest.prototype.get = function(keys, callback) {
   var isMultipleRequest = Array.isArray(keys);
   keys = isMultipleRequest ? keys : [keys];
   callback = callback || util.noop;
-  var req = new pb.LookupRequest({
+  var req = {
     key: keys.map(entity.keyToKeyProto)
-  });
-  var res = pb.LookupResponse;
-  if (this.id) {
-    req.transaction = this.id;
-  }
-  this.createRequest_('lookup', req, res, function(err, resp) {
+  };
+  this.makeReq_('lookup', req, function(err, resp) {
     if (err) {
       callback(err);
       return;
@@ -217,7 +213,6 @@ DatastoreRequest.prototype.save = function(entities, callback) {
     return entityObject.key;
   });
   var req = {
-    mode: MODE_NON_TRANSACTIONAL,
     mutation: entities.reduce(function(acc, entityObject, index) {
       var ent = {};
       if (Array.isArray(entityObject.data)) {
@@ -242,13 +237,7 @@ DatastoreRequest.prototype.save = function(entities, callback) {
       return acc;
     }.bind(this), { upsert: [], insert_auto_id: [] })
   };
-  if (this.id) {
-    req.transaction = this.id;
-    req.mode = MODE_TRANSACTIONAL;
-  }
-  req = new pb.CommitRequest(req);
-  var res = pb.CommitResponse;
-  this.createRequest_('commit', req, res, function(err, resp) {
+  this.makeReq_('commit', req, function(err, resp) {
     if (err || !resp) {
       callback(err);
       return;
@@ -290,20 +279,12 @@ DatastoreRequest.prototype.delete = function(keys, callback) {
   var isMultipleRequest = Array.isArray(keys);
   keys = isMultipleRequest ? keys : [keys];
   callback = callback || util.noop;
-
   var req = {
-    mode: MODE_NON_TRANSACTIONAL,
     mutation: {
       delete: keys.map(entity.keyToKeyProto)
     }
   };
-  if (this.id) {
-    req.transaction = this.id;
-    req.mode = MODE_TRANSACTIONAL;
-  }
-  req = new pb.CommitRequest(req);
-  var res = pb.CommitResponse;
-  this.createRequest_('commit', req, res, function(err) {
+  this.makeReq_('commit', req, function(err) {
     if (!err && this.id) {
       this.isFinalized = true;
     }
@@ -334,7 +315,6 @@ DatastoreRequest.prototype.delete = function(keys, callback) {
  *   }
  * });
  */
-
 DatastoreRequest.prototype.runQuery = function(q, callback) {
   callback = callback || util.noop;
   var req = {
@@ -342,20 +322,13 @@ DatastoreRequest.prototype.runQuery = function(q, callback) {
     query: entity.queryToQueryProto(q)
   };
 
-  if (this.id) {
-    req.read_options.transaction = this.id;
-  }
-
   if (q.namespace) {
     req.partition_id = {
       namespace: q.namespace
     };
   }
 
-  req = new pb.RunQueryRequest(req);
-  var res = pb.RunQueryResponse;
-
-  this.createRequest_('runQuery', req, res, function(err, resp) {
+  this.makeReq_('runQuery', req, function(err, resp) {
     if (err || !resp.batch || !resp.batch.entity_result) {
       callback(err);
       return;
@@ -406,11 +379,10 @@ DatastoreRequest.prototype.allocateIds = function(incompleteKey, n, callback) {
   for (var i = 0; i < n; i++) {
     incompleteKeys.push(entity.keyToKeyProto(incompleteKey));
   }
-
-  this.createRequest_(
-      'allocateIds',
-      new pb.AllocateIdsRequest({ key: incompleteKeys }),
-      pb.AllocateIdsResponse, function(err, resp) {
+  var req = {
+    key: incompleteKeys
+  };
+  this.makeReq_('allocateIds', req, function(err, resp) {
     if (err) {
       callback(err);
       return;
@@ -424,28 +396,50 @@ DatastoreRequest.prototype.allocateIds = function(incompleteKey, n, callback) {
 };
 
 /**
- * Make a request to the API endpoint.
+ * Make a request to the API endpoint. Properties to indicate a transactional or
+ * non-transactional operation are added automatically.
  *
- * @param {string} method - Transaction action (allocateIds, commit, etc.).
- * @param {object} req - Request configuration object.
- * @param {object} respType - Response type.
- * @param {function} cb - The callback function.
+ * @param {string} method - Datastore action (allocateIds, commit, etc.).
+ * @param {object=} body - Request configuration object.
+ * @param {function} callback - The callback function.
  *
  * @private
  *
  * @example
  * var deleteRequest = {
- *   MODE: 'NON_TRANSACTIONAL',
  *   mutation: {
  *     delete: [] // datastore key objects.
  *   }
  * };
  * transaction.makeReq('commit', deleteRequest, function(err) {});
  */
-DatastoreRequest.prototype.createRequest_ =
-    function(method, req, respType, cb) {
+DatastoreRequest.prototype.makeReq_ = function(method, body, callback) {
   // TODO: Handle non-HTTP 200 cases.
-  cb = cb || util.noop;
+  if (!callback) {
+    callback = body;
+    body = {};
+  }
+  callback = callback || util.noop;
+
+  // Set properties to indicate if we're in a transaction or not.
+  if (method === 'commit') {
+    if (this.id) {
+      body.mode = MODE_TRANSACTIONAL;
+      body.transaction = this.id;
+    } else {
+      body.mode = MODE_NON_TRANSACTIONAL;
+    }
+  }
+
+  if (method === 'lookup' && this.id) {
+    body.read_options = body.read_options || {};
+    body.read_options.transaction = this.id;
+  }
+
+  var pbKey = method[0].toUpperCase() + method.substr(1);
+  var pbRequest = new pb[pbKey + 'Request'](body).toBuffer();
+  var pbResponse = pb[pbKey + 'Response'];
+
   this.connection.createAuthorizedReq({
     method: 'POST',
     host: GOOGLE_APIS_HOST,
@@ -455,7 +449,7 @@ DatastoreRequest.prototype.createRequest_ =
     }
   }, function(err, request) {
     if (err) {
-      cb(err);
+      callback(err);
       return;
     }
     var remoteStream = https.request(request, function(resp) {
@@ -466,15 +460,15 @@ DatastoreRequest.prototype.createRequest_ =
       resp.on('end', function() {
         util.handleResp(null, resp, buffer.toString(), function(err) {
           if (err) {
-            cb(err);
+            callback(err);
             return;
           }
-          cb(null, respType.decode(buffer));
+          callback(null, pbResponse.decode(buffer));
         });
       });
     });
-    remoteStream.on('error', cb);
-    remoteStream.write(req.toBuffer());
+    remoteStream.on('error', callback);
+    remoteStream.write(pbRequest);
     remoteStream.end();
   });
 };
diff --git a/lib/datastore/transaction.js b/lib/datastore/transaction.js
index 0d68ea8048e..dda603cc4b9 100644
--- a/lib/datastore/transaction.js
+++ b/lib/datastore/transaction.js
@@ -22,12 +22,6 @@
 
 var nodeutil = require('util');
 
-/**
- * @type module:datastore/pb
- * @private
- */
-var pb = require('./pb.js');
-
 /**
  * @type module:common/util
  * @private
@@ -66,11 +60,9 @@ var DatastoreRequest = require('./request.js');
  */
 function Transaction(connection, projectId) {
   this.connection = connection;
-  this.projectId = projectId;
-  // the default transaction has no id.
-  // if id is not set, run operations non-transactional.
   this.id = null;
   this.isFinalized = false;
+  this.projectId = projectId;
 }
 
 nodeutil.inherits(Transaction, DatastoreRequest);
@@ -96,17 +88,14 @@ nodeutil.inherits(Transaction, DatastoreRequest);
  */
 Transaction.prototype.begin = function(callback) {
   callback = callback || util.noop;
-  var that = this;
-  var req = new pb.BeginTransactionRequest();
-  var res = pb.BeginTransactionResponse;
-  this.createRequest_('beginTransaction', req, res, function(err, resp) {
+  this.makeReq_('beginTransaction', function(err, resp) {
     if (err) {
       callback(err);
       return;
     }
-    that.id = resp.transaction;
+    this.id = resp.transaction;
     callback(null);
-  });
+  }.bind(this));
 };
 
 /**
@@ -125,13 +114,10 @@ Transaction.prototype.begin = function(callback) {
  */
 Transaction.prototype.rollback = function(callback) {
   callback = callback || util.noop;
-  var that = this;
-  var req = new pb.RollbackRequest({ transaction: this.id });
-  var res = pb.RollbackResponse;
-  this.createRequest_('rollback', req, res, function(err) {
-    that.isFinalized = true;
+  this.makeReq_('rollback', function(err) {
+    this.isFinalized = true;
     callback(err || null);
-  });
+  }.bind(this));
 };
 
 /**
@@ -150,17 +136,14 @@ Transaction.prototype.rollback = function(callback) {
  */
 Transaction.prototype.commit = function(callback) {
   callback = callback || util.noop;
-  var that = this;
-  var req = new pb.CommitRequest({ transaction: this.id });
-  var res = pb.CommitResponse;
-  this.createRequest_('commit', req, res, function(err) {
+  this.makeReq_('commit', function(err) {
     if (err) {
       callback(err);
       return;
     }
-    that.isFinalized = true;
+    this.isFinalized = true;
     callback(null);
-  });
+  }.bind(this));
 };
 
 /**
diff --git a/test/datastore/request.js b/test/datastore/request.js
index 33988d1a1a7..0b4d28b1d95 100644
--- a/test/datastore/request.js
+++ b/test/datastore/request.js
@@ -23,22 +23,39 @@ var ByteBuffer = require('bytebuffer');
 var duplexify = require('duplexify');
 var entity = require('../../lib/datastore/entity.js');
 var mockRespGet = require('../testdata/response_get.json');
+var pb = require('../../lib/datastore/pb.js');
 var Query = require('../../lib/datastore/query.js');
 var util = require('../../lib/common/util.js');
 
 var httpsRequestOverride = util.noop;
 var https = {
   request: function() {
-    var result = httpsRequestOverride.apply(this, util.toArray(arguments));
+    var requestFn = httpsRequestOverride;
     httpsRequestOverride = util.noop;
-    return result;
+    return requestFn.apply(this, util.toArray(arguments));
+  }
+};
+
+// Create a protobuf "FakeMethod" request & response.
+pb.FakeMethodRequest = function() {
+  this.toBuffer = function() {
+    return new Buffer('');
+  };
+};
+var pbFakeMethodResponseDecode = util.noop;
+pb.FakeMethodResponse = {
+  decode: function() {
+    var decodeFn = pbFakeMethodResponseDecode;
+    pbFakeMethodResponseDecode = util.noop;
+    return decodeFn.apply(this, util.toArray(arguments));
   }
 };
 
 var Request = require('sandboxed-module')
   .require('../../lib/datastore/request.js', {
     requires: {
-      'https': https
+      'https': https,
+      './pb.js': pb
     }
   });
 
@@ -56,9 +73,9 @@ describe('Request', function() {
 
   describe('get', function() {
     it('should get by key', function(done) {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'lookup');
-        assert.equal(proto.key.length, 1);
+        assert.equal(req.key.length, 1);
         callback(null, mockRespGet);
       };
       request.get(key, function(err, entity) {
@@ -72,9 +89,9 @@ describe('Request', function() {
     });
 
     it('should multi get by keys', function(done) {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'lookup');
-        assert.equal(proto.key.length, 1);
+        assert.equal(req.key.length, 1);
         callback(null, mockRespGet);
       };
       request.get([key], function(err, entities) {
@@ -90,7 +107,7 @@ describe('Request', function() {
 
     it('should continue looking for deferred results', function(done) {
       var lookupCount = 0;
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         lookupCount++;
         assert.equal(method, 'lookup');
         if (mockRespGet.deferred.length) {
@@ -111,9 +128,9 @@ describe('Request', function() {
 
   describe('save', function() {
     it('should save with incomplete key', function(done) {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'commit');
-        assert.equal(proto.mutation.insert_auto_id.length, 1);
+        assert.equal(req.mutation.insert_auto_id.length, 1);
         callback();
       };
       var key = new entity.Key({ namespace: 'ns', path: ['Company'] });
@@ -121,12 +138,12 @@ describe('Request', function() {
     });
 
     it('should save with keys', function(done) {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'commit');
-        assert.equal(proto.mutation.upsert.length, 2);
-        assert.equal(proto.mutation.upsert[0].property[0].name, 'k');
+        assert.equal(req.mutation.upsert.length, 2);
+        assert.equal(req.mutation.upsert[0].property[0].name, 'k');
         assert.equal(
-          proto.mutation.upsert[0].property[0].value.string_value, 'v');
+          req.mutation.upsert[0].property[0].value.string_value, 'v');
         callback();
       };
       request.save([
@@ -143,7 +160,7 @@ describe('Request', function() {
 
       it('should mark transaction as finalized', function(done) {
         assert.strictEqual(request.isFinalized, undefined);
-        request.createRequest_ = function(method, proto, typ, callback) {
+        request.makeReq_ = function(method, req, callback) {
           callback(null, { mutation_result: {} });
         };
         request.save({ key: key, data: {} }, function(err) {
@@ -155,7 +172,7 @@ describe('Request', function() {
 
       it('should not mark as finalized if an error occurred', function(done) {
         assert.strictEqual(request.isFinalized, undefined);
-        request.createRequest_ = function(method, proto, typ, callback) {
+        request.makeReq_ = function(method, req, callback) {
           callback(new Error('Error.'));
         };
         request.save({ key: key, data: {} }, function() {
@@ -165,11 +182,11 @@ describe('Request', function() {
       });
 
       it('should not set an indexed value by default', function(done) {
-        request.createRequest_ = function(method, proto) {
-          var property = proto.mutation.upsert[0].property[0];
+        request.makeReq_ = function(method, req) {
+          var property = req.mutation.upsert[0].property[0];
           assert.equal(property.name, 'name');
           assert.equal(property.value.string_value, 'value');
-          assert.strictEqual(property.value.indexed, null);
+          assert.strictEqual(property.value.indexed, undefined);
           done();
         };
         request.save({
@@ -179,8 +196,8 @@ describe('Request', function() {
       });
 
       it('should allow setting the indexed value of property', function(done) {
-        request.createRequest_ = function(method, proto) {
-          var property = proto.mutation.upsert[0].property[0];
+        request.makeReq_ = function(method, req) {
+          var property = req.mutation.upsert[0].property[0];
           assert.equal(property.name, 'name');
           assert.equal(property.value.string_value, 'value');
           assert.strictEqual(property.value.indexed, false);
@@ -196,18 +213,18 @@ describe('Request', function() {
 
   describe('delete', function() {
     it('should delete by key', function(done) {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'commit');
-        assert.equal(!!proto.mutation.delete, true);
+        assert.equal(!!req.mutation.delete, true);
         callback();
       };
       request.delete(key, done);
     });
 
     it('should multi delete by keys', function(done) {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'commit');
-        assert.equal(proto.mutation.delete.length, 2);
+        assert.equal(req.mutation.delete.length, 2);
         callback();
       };
       request.delete([ key, key ], done);
@@ -221,7 +238,7 @@ describe('Request', function() {
 
       it('should mark transaction as finalized', function(done) {
         assert.strictEqual(request.isFinalized, undefined);
-        request.createRequest_ = function(method, proto, typ, callback) {
+        request.makeReq_ = function(method, req, callback) {
           callback(null, { mutation_result: {} });
         };
         request.delete(key, function(err) {
@@ -233,7 +250,7 @@ describe('Request', function() {
 
       it('should not mark as finalized if an error occurred', function(done) {
         assert.strictEqual(request.isFinalized, undefined);
-        request.createRequest_ = function(method, proto, typ, callback) {
+        request.makeReq_ = function(method, req, callback) {
           callback(new Error('Error.'));
         };
         request.delete(key, function() {
@@ -266,7 +283,7 @@ describe('Request', function() {
     describe('errors', function() {
       it('should handle upstream errors', function() {
         var error = new Error('Error.');
-        request.createRequest_ = function(method, proto, typ, callback) {
+        request.makeReq_ = function(method, req, callback) {
           assert.equal(method, 'runQuery');
           callback(error);
         };
@@ -277,7 +294,7 @@ describe('Request', function() {
       });
 
       it('should handle missing results error', function() {
-        request.createRequest_ = function(method, proto, typ, callback) {
+        request.makeReq_ = function(method, req, callback) {
           assert.equal(method, 'runQuery');
           callback(null, mockResponse.withoutResults);
         };
@@ -290,7 +307,7 @@ describe('Request', function() {
     });
 
     it('should execute callback with results', function() {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'runQuery');
         callback(null, mockResponse.withResults);
       };
@@ -307,7 +324,7 @@ describe('Request', function() {
     });
 
     it('should return a new query if results remain', function() {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'runQuery');
         callback(null, mockResponse.withResultsAndEndCursor);
       };
@@ -321,13 +338,9 @@ describe('Request', function() {
 
   describe('allocateIds', function() {
     it('should produce proper allocate IDs req protos', function(done) {
-      request.createRequest_ = function(method, proto, typ, callback) {
+      request.makeReq_ = function(method, req, callback) {
         assert.equal(method, 'allocateIds');
-        assert.equal(proto.key.length, 1);
-        assert.deepEqual(proto.key[0], {
-          partition_id: null,
-          path_element :[{ kind: 'Kind', name: null, id: null }]
-        });
+        assert.equal(req.key.length, 1);
         callback(null, {
           key: [
             { path_element: [{ kind: 'Kind', id: 123 }] }
@@ -350,12 +363,7 @@ describe('Request', function() {
     });
   });
 
-  describe('createRequest_', function() {
-    var mockProtoRequest = { fake: 'request' };
-    mockProtoRequest.toBuffer = function() {
-      return mockProtoRequest;
-    };
-
+  describe('makeReq_', function() {
     beforeEach(function() {
       request.connection = {
         createAuthorizedReq: util.noop
@@ -373,11 +381,11 @@ describe('Request', function() {
         assert.equal(opts.headers['content-type'], 'application/x-protobuf');
         done();
       };
-      request.createRequest_(method, null, null, util.noop);
+      request.makeReq_(method, {}, util.noop);
     });
 
     it('should make https request', function(done) {
-      var mockRequest = { fake: 'request' };
+      var mockRequest = { mock: 'request' };
       httpsRequestOverride = function(req) {
         assert.deepEqual(req, mockRequest);
         done();
@@ -386,7 +394,115 @@ describe('Request', function() {
       request.connection.createAuthorizedReq = function(opts, callback) {
         callback(null, mockRequest);
       };
-      request.createRequest_('commit', mockProtoRequest, null, util.noop);
+      request.makeReq_('commit', {}, util.noop);
+    });
+
+    it('should send protobuf request', function(done) {
+      var requestOptions = { mode: 'NON_TRANSACTIONAL' };
+      var decoded = new pb.CommitRequest(requestOptions).toBuffer();
+      httpsRequestOverride = function() {
+        var stream = { on: util.noop, end: util.noop };
+        stream.write = function(data) {
+          assert.equal(String(data), String(decoded));
+          done();
+        };
+        return stream;
+      };
+      request.connection.createAuthorizedReq = function(opts, callback) {
+        callback();
+      };
+      request.makeReq_('commit', requestOptions, util.noop);
+    });
+
+    it('should decode protobuf response', function(done) {
+      pbFakeMethodResponseDecode = function() {
+        done();
+      };
+      httpsRequestOverride = function(req, callback) {
+        var responseStream = duplexify();
+        callback(responseStream);
+        responseStream.emit('end');
+        return duplexify();
+      };
+      request.connection.createAuthorizedReq = function(opts, callback) {
+        callback();
+      };
+      request.makeReq_('fakeMethod', util.noop);
+    });
+
+    describe('transactional and non-transactional properties', function() {
+      beforeEach(function() {
+        request.connection.createAuthorizedReq = function(opts, callback) {
+          callback();
+        };
+      });
+
+      describe('commit', function() {
+        it('should attach transactional properties', function(done) {
+          request.id = 'transaction-id';
+          var expected = new pb.CommitRequest({
+            mode: 'TRANSACTIONAL',
+            transaction: request.id
+          }).toBuffer();
+          httpsRequestOverride = function() {
+            var stream = { on: util.noop, end: util.noop };
+            stream.write = function(data) {
+              assert.deepEqual(data, expected);
+              done();
+            };
+            return stream;
+          };
+          request.makeReq_('commit', util.noop);
+        });
+
+        it('should attach non-transactional properties', function(done) {
+          var expected = new pb.CommitRequest({
+            mode: 'NON_TRANSACTIONAL'
+          }).toBuffer();
+          httpsRequestOverride = function() {
+            var stream = { on: util.noop, end: util.noop };
+            stream.write = function(data) {
+              assert.deepEqual(data, expected);
+              done();
+            };
+            return stream;
+          };
+          request.makeReq_('commit', util.noop);
+        });
+      });
+
+      describe('lookup', function() {
+        it('should attach transactional properties', function(done) {
+          request.id = 'transaction-id';
+          var expected = new pb.LookupRequest({
+            read_options: {
+              transaction: request.id
+            }
+          }).toBuffer();
+          httpsRequestOverride = function() {
+            var stream = { on: util.noop, end: util.noop };
+            stream.write = function(data) {
+              assert.deepEqual(data, expected);
+              done();
+            };
+            return stream;
+          };
+          request.makeReq_('lookup', util.noop);
+        });
+
+        it('should not attach transactional properties', function(done) {
+          var expected = new pb.LookupRequest().toBuffer();
+          httpsRequestOverride = function() {
+            var stream = { on: util.noop, end: util.noop };
+            stream.write = function(data) {
+              assert.deepEqual(data, expected);
+              done();
+            };
+            return stream;
+          };
+          request.makeReq_('lookup', util.noop);
+        });
+      });
     });
   });
 });
diff --git a/test/datastore/transaction.js b/test/datastore/transaction.js
index dc3d87f400e..848627dd90e 100644
--- a/test/datastore/transaction.js
+++ b/test/datastore/transaction.js
@@ -31,7 +31,8 @@ describe('Transaction', function() {
 
   describe('begin', function() {
     it('should begin', function(done) {
-      transaction.createRequest_ = function(method) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         assert.equal(method, 'beginTransaction');
         done();
       };
@@ -39,7 +40,8 @@ describe('Transaction', function() {
     });
 
     it('should set transaction id', function(done) {
-      transaction.createRequest_ = function(method, proto, respType, callback) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         callback(null, { transaction: TRANSACTION_ID });
       };
       transaction.begin(function(err) {
@@ -51,7 +53,8 @@ describe('Transaction', function() {
 
     it('should pass error to callback', function(done) {
       var error = new Error('Error.');
-      transaction.createRequest_ = function(method, proto, respType, callback) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         callback(error);
       };
       transaction.begin(function(err) {
@@ -67,11 +70,8 @@ describe('Transaction', function() {
     });
 
     it('should rollback', function(done) {
-      transaction.createRequest_ = function(method, proto) {
+      transaction.makeReq_ = function(method) {
         assert.equal(method, 'rollback');
-        assert.equal(
-          proto.transaction.toBase64(),
-          new Buffer(transaction.id).toString('base64'));
         done();
       };
       transaction.rollback();
@@ -79,7 +79,8 @@ describe('Transaction', function() {
 
     it('should pass error to callback', function(done) {
       var error = new Error('Error.');
-      transaction.createRequest_ = function(method, proto, respType, callback) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         callback(error);
       };
       transaction.rollback(function(err) {
@@ -89,7 +90,8 @@ describe('Transaction', function() {
     });
 
     it('should mark as finalized', function(done) {
-      transaction.createRequest_ = function(method, proto, respType, callback) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         callback();
       };
       transaction.rollback(function() {
@@ -99,8 +101,9 @@ describe('Transaction', function() {
     });
 
     it('should mark as finalized when rollback errors', function(done) {
-      transaction.createRequest_ = function(method, proto, respType, callback) {
-       callback(new Error('Error.'));
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
+        callback(new Error('Error.'));
       };
       transaction.rollback(function() {
         assert.strictEqual(transaction.isFinalized, true);
@@ -115,11 +118,8 @@ describe('Transaction', function() {
     });
 
     it('should commit', function(done) {
-      transaction.createRequest_ = function(method, proto) {
+      transaction.makeReq_ = function(method) {
         assert.equal(method, 'commit');
-        assert.equal(
-          proto.transaction.toBase64(),
-          new Buffer(transaction.id).toString('base64'));
         done();
       };
       transaction.commit();
@@ -127,7 +127,8 @@ describe('Transaction', function() {
 
     it('should pass error to callback', function(done) {
       var error = new Error('Error.');
-      transaction.createRequest_ = function(method, proto, respType, callback) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         callback(error);
       };
       transaction.commit(function(err) {
@@ -137,7 +138,8 @@ describe('Transaction', function() {
     });
 
     it('should mark as finalized', function(done) {
-      transaction.createRequest_ = function(method, proto, respType, callback) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         callback();
       };
       transaction.commit(function() {
@@ -147,7 +149,8 @@ describe('Transaction', function() {
     });
 
     it('should not mark as finalized if commit errors', function(done) {
-      transaction.createRequest_ = function(method, proto, respType, callback) {
+      transaction.makeReq_ = function(method, req, callback) {
+        callback = callback || req;
         callback(new Error('Error.'));
       };
       transaction.commit(function() {