Add automatic generation of UUID primary keys.

When saving new records we should have hooks to populate the primary
keys of entities in through the type system. This restores the auto-uuid
population, and allows user defined types to populate as well.

Add a new integration test to ensure saving/updating/deleting works as expected.

Cake/ORM/Table.php

@@ -18,6 +18,7 @@
 
 use Cake\Core\App;
 use Cake\Database\Schema\Table as Schema;
+use Cake\Database\Type;
 use Cake\Event\Event;
 use Cake\Event\EventManager;
 use Cake\ORM\Association\BelongsTo;
@@ -865,15 +866,30 @@ protected function _processSave($entity, $options) {
  */
 	protected function _insert($entity, $data) {
 		$query = $this->_buildQuery();
+
+		$id = null;
+		$primary = $this->primaryKey();
+		if ($primary) {
+			$typeName = $this->schema()->columnType($primary);
+			$type = Type::build($typeName);
+			$id = $type->newId();
+		}
+		if ($id !== null) {
+			$data[$primary] = $id;
+		}
+
 		$statement = $query->insert($this->table(), array_keys($data))
 			->values($data)
 			->executeStatement();
 
 		$success = false;
 		if ($statement->rowCount() > 0) {
-			$primary = $this->primaryKey();
-			$id = $statement->lastInsertId($this->table(), $primary);
-			$entity->set($primary, $id);
+			if (!isset($data[$primary])) {
+				$id = $statement->lastInsertId($this->table(), $primary);
+			}
+			if ($id !== null) {
+				$entity->set($primary, $id);
+			}
 			$entity->clean();
 			$success = $entity;
 		}

Cake/Test/TestCase/ORM/TableUuidTest.php

@@ -0,0 +1,116 @@
+<?php
+/**
+ * PHP Version 5.4
+ *
+ * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
+ * @link          http://cakephp.org CakePHP(tm) Project
+ * @since         CakePHP(tm) v 3.0.0
+ * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+namespace Cake\Test\TestCase\ORM;
+
+use Cake\Core\Configure;
+use Cake\Database\ConnectionManager;
+use Cake\Database\Expression\QueryExpression;
+use Cake\ORM\Table;
+use Cake\ORM\TableRegistry;
+use Cake\Utility\String;
+
+/**
+ * Integration tests for Table class with uuid primary keys.
+ *
+ */
+class UuidTableTest extends \Cake\TestSuite\TestCase {
+
+/**
+ * Fixtures
+ *
+ * @var array
+ */
+	public $fixtures = [
+		'core.uuiditem', 'core.uuidportfolio'
+	];
+
+/**
+ * setup
+ *
+ * @return void
+ */
+	public function setUp() {
+		parent::setUp();
+		$this->connection = ConnectionManager::get('test');
+		Configure::write('App.namespace', 'TestApp');
+	}
+
+/**
+ * teardown
+ *
+ * @return void
+ */
+	public function tearDown() {
+		parent::tearDown();
+		TableRegistry::clear();
+	}
+
+/**
+ * Test saving new records sets uuids
+ *
+ * @return void
+ */
+	public function testSaveNew() {
+		$entity = new \Cake\ORM\Entity([
+			'name' => 'shiny new',
+			'published' => true,
+		]);
+		$table = TableRegistry::get('uuiditems');
+		$this->assertSame($entity, $table->save($entity));
+		$this->assertRegExp('/^[a-f0-9-]{36}$/', $entity->id, 'Should be 36 characters');
+
+		$row = $table->find('all')->where(['id' => $entity->id])->first();
+		$this->assertEquals($entity->toArray(), $row->toArray());
+	}
+
+/**
+ * Test saving existing records works
+ *
+ * @return void
+ */
+	public function testSaveUpdate() {
+		$id = '481fc6d0-b920-43e0-a40d-6d1740cf8569';
+		$entity = new \Cake\ORM\Entity([
+			'id' => $id,
+			'name' => 'shiny update',
+			'published' => true,
+		]);
+
+		$table = TableRegistry::get('uuiditems');
+		$this->assertSame($entity, $table->save($entity));
+		$this->assertEquals($id, $entity->id, 'Should be 36 characters');
+
+		$row = $table->find('all')->where(['id' => $entity->id])->first();
+		$this->assertEquals($entity->toArray(), $row->toArray());
+	}
+
+/**
+ * Test delete with string pk.
+ *
+ * @return void
+ */
+	public function testDelete() {
+		$id = '481fc6d0-b920-43e0-a40d-6d1740cf8569';
+		$table = TableRegistry::get('uuiditems');
+		$entity = $table->find('all')->where(['id' => $id])->first();
+
+		$this->assertTrue($table->delete($entity));
+		$query = $table->find('all')->where(['id' => $id]);
+		$this->assertCount(0, $query->execute(), 'No rows left');
+	}
+
+}