Add methods to switch to master or random slave.

src/Connection/Aggregate/MasterSlaveReplication.php

@@ -150,6 +150,10 @@ class MasterSlaveReplication implements ReplicationInterface
             $connection = $this->getConnectionById($connection);
         }
 
+        if (!$connection) {
+            throw new \InvalidArgumentException('Invalid connection or connection not found.');
+        }
+
         if ($connection !== $this->master && !in_array($connection, $this->slaves, true)) {
             throw new \InvalidArgumentException('Invalid connection or connection not found.');
         }
@@ -157,6 +161,23 @@ class MasterSlaveReplication implements ReplicationInterface
         $this->current = $connection;
     }
 
+    /**
+     * Switches to the master server.
+     */
+    public function switchToMaster()
+    {
+        $this->switchTo('master');
+    }
+
+    /**
+     * Switches to a random slave server.
+     */
+    public function switchToSlave()
+    {
+        $connection = $this->pickSlave();
+        $this->switchTo($connection);
+    }
+
     /**
      * {@inheritdoc}
      */

tests/Predis/Connection/Aggregate/MasterSlaveReplicationTest.php

@@ -191,7 +191,7 @@ class MasterSlaveReplicationTest extends PredisTestCase
      * @expectedException \InvalidArgumentException
      * @expectedExceptionMessage Invalid connection or connection not found.
      */
-    public function testThrowsErrorWhenSwitchingToUnknownConnection()
+    public function testThrowsErrorWhenSwitchingToUnknownConnectionByAlias()
     {
         $replication = new MasterSlaveReplication();
         $replication->add($this->getMockConnection('tcp://host1?alias=master'));
@@ -200,6 +200,113 @@ class MasterSlaveReplicationTest extends PredisTestCase
         $replication->switchTo('unknown');
     }
 
+    /**
+     * @group disconnected
+     */
+    public function testCanSwitchConnectionByInstance()
+    {
+        $master = $this->getMockConnection('tcp://host1?alias=master');
+        $slave1 = $this->getMockConnection('tcp://host2?alias=slave1');
+
+        $replication = new MasterSlaveReplication();
+        $replication->add($master);
+        $replication->add($slave1);
+
+        $this->assertNull($replication->getCurrent());
+
+        $replication->switchTo($master);
+        $this->assertSame($master, $replication->getCurrent());
+        $replication->switchTo($slave1);
+        $this->assertSame($slave1, $replication->getCurrent());
+    }
+
+    /**
+     * @group disconnected
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Invalid connection or connection not found.
+     */
+    public function testThrowsErrorWhenSwitchingToUnknownConnectionByInstance()
+    {
+        $replication = new MasterSlaveReplication();
+        $replication->add($this->getMockConnection('tcp://host1?alias=master'));
+        $replication->add($this->getMockConnection('tcp://host2?alias=slave1'));
+
+        $slave2 = $this->getMockConnection('tcp://host3?alias=slave2');
+
+        $replication->switchTo($slave2);
+    }
+
+    /**
+     * @group disconnected
+     */
+    public function testCanSwitchToMaster()
+    {
+        $master = $this->getMockConnection('tcp://host1?alias=master');
+        $slave1 = $this->getMockConnection('tcp://host2?alias=slave1');
+        $slave2 = $this->getMockConnection('tcp://host3?alias=slave2');
+
+        $replication = new MasterSlaveReplication();
+        $replication->add($master);
+        $replication->add($slave1);
+        $replication->add($slave2);
+
+        $this->assertNull($replication->getCurrent());
+
+        $replication->switchToMaster();
+        $this->assertSame($master, $replication->getCurrent());
+    }
+
+    /**
+     * @group disconnected
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Invalid connection or connection not found.
+     */
+    public function testThrowsErrorOnSwitchToMasterWithNoMasterDefined()
+    {
+        $slave1 = $this->getMockConnection('tcp://host2?alias=slave1');
+
+        $replication = new MasterSlaveReplication();
+        $replication->add($slave1);
+
+        $replication->switchToMaster();
+    }
+
+    /**
+     * @group disconnected
+     * @todo We should find a way to test that the slave is indeed randomly selected.
+     */
+    public function testCanSwitchToRandomSlave()
+    {
+        $master = $this->getMockConnection('tcp://host1?alias=master');
+        $slave1 = $this->getMockConnection('tcp://host2?alias=slave1');
+        $slave2 = $this->getMockConnection('tcp://host3?alias=slave2');
+
+        $replication = new MasterSlaveReplication();
+        $replication->add($master);
+        $replication->add($slave1);
+        $replication->add($slave2);
+
+        $this->assertNull($replication->getCurrent());
+
+        $replication->switchToSlave();
+        $this->assertSame($slave1, $replication->getCurrent());
+    }
+
+    /**
+     * @group disconnected
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Invalid connection or connection not found.
+     */
+    public function testThrowsErrorOnSwitchToRandomSlaveWithNoSlavesDefined()
+    {
+        $master = $this->getMockConnection('tcp://host1?alias=master');
+
+        $replication = new MasterSlaveReplication();
+        $replication->add($master);
+
+        $replication->switchToSlave();
+    }
+
     /**
      * @group disconnected
      */