diff --git a/README.md b/README.md
index 31fb58f..4176ad0 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,10 @@ CpuCoreCountFlexible::createFromClass('WyriHaximus\React\ChildProcess\Messenger\
 });
 ```
 
+## Updating options during run time
+
+A new feature in `1.5` is the `setOptions` method on pools. Which allows you to update a pools settings. This feature allows you to scale the amount of workers up and down when needed.
+
 ## License ##
 
 Copyright 2016 [Cees-Jan Kiewiet](http://wyrihaximus.net/)
diff --git a/appveyor.yml b/appveyor.yml
index d559ba9..36e80ee 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -39,7 +39,7 @@ init:
 ## Install PHP and composer, and run the appropriate composer command
 install:
     - IF EXIST c:\tools\php (SET PHP=0)
-    - ps: appveyor-retry cinst -y php --version ((choco search php --exact --all-versions -r | select-string -pattern $Env:php_ver_target | Select-Object -first 1) -replace '[php|]','')
+    - ps: appveyor-retry cinst -y php --ignore-checksums --version ((choco search php --exact --all-versions -r | select-string -pattern $Env:php_ver_target | Select-Object -first 1) -replace '[php|]','')
     - cd c:\tools\php
     - IF %PHP%==1 copy php.ini-production php.ini /Y
     - IF %PHP%==1 echo date.timezone="UTC" >> php.ini
diff --git a/examples/ping-pong-set-options/README.md b/examples/ping-pong-set-options/README.md
new file mode 100644
index 0000000..3f144fc
--- /dev/null
+++ b/examples/ping-pong-set-options/README.md
@@ -0,0 +1,5 @@
+To start use the following command:
+
+```sh
+time php ping.php
+```
diff --git a/examples/ping-pong-set-options/ping.php b/examples/ping-pong-set-options/ping.php
new file mode 100644
index 0000000..acbc191
--- /dev/null
+++ b/examples/ping-pong-set-options/ping.php
@@ -0,0 +1,97 @@
+<?php
+
+require dirname(dirname(__DIR__)) . '/vendor/autoload.php';
+
+use React\ChildProcess\Process;
+use React\EventLoop\Factory;
+use WyriHaximus\React\ChildProcess\Pool\Factory\Fixed;
+use WyriHaximus\React\ChildProcess\Pool\Factory\Flexible;
+use WyriHaximus\React\ChildProcess\Pool\Options;
+use WyriHaximus\React\ChildProcess\Pool\PoolInterface;
+
+const POOL_PROCESS_COUNT = 10;
+const I = 512;
+
+echo 'Warning this example can be rather harsh on your hardware, stop now or continue with cation!!!!', PHP_EOL;
+echo 'Starting a pool with ' . POOL_PROCESS_COUNT . ' child processes looping from 0 till ' . I . ' and calculating $i * $i * $i * $i in the child process.';
+echo PHP_EOL;
+echo 'Starting in:', PHP_EOL, '5', PHP_EOL;
+sleep(1);
+echo '4', PHP_EOL;
+sleep(1);
+echo '3', PHP_EOL;
+sleep(1);
+echo '2', PHP_EOL;
+sleep(1);
+echo '1', PHP_EOL;
+sleep(1);
+
+$loop = Factory::create();
+//Flexible::create(new Process('php ' . dirname(dirname(__DIR__)) . '/examples/ping-pong/pong.php'), $loop)->then(function (PoolInterface $pool) use ($loop) {
+Fixed::create(new Process('php ' . dirname(dirname(__DIR__)) . '/examples/ping-pong/pong.php'), $loop)->then(function (PoolInterface $pool) use ($loop) {
+    $pool->on('message', function ($message) {
+        var_export($message);
+    });
+
+    $pool->on('error', function ($e) {
+        echo 'Error: ', var_export($e, true), PHP_EOL;
+    });
+
+    for ($i = 0; $i < I; $i++) {
+        echo $i, PHP_EOL;
+        $j = $i;
+        $pool->rpc(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::rpc('ping', [
+            'i' => $i,
+            's' => str_pad('', 512, '.'),
+        ]))->then(function ($data) use ($j) {
+            echo 'Answer for ' . $j . ' * ' . $j . ' * ' . $j . ' * ' . $j . ': ', $data['result'], PHP_EOL;
+        }, function ($error) {
+            var_export($error);
+            die();
+        });
+    }
+
+    $timer = $loop->addPeriodicTimer(0.1, function () use ($pool) {
+        echo 'Pool status: ', PHP_EOL;
+        foreach ($pool->info() as $key => $value) {
+            echo "\t", $key, ': ', $value, PHP_EOL;
+        }
+    });
+
+    for ($i = 1; $i < 120; $i = $i + mt_rand(1, 20)) {
+        $loop->addTimer($i, function () use ($pool) {
+            //$pool->setOption(Options::MAX_SIZE, mt_rand(1, 20));
+            $pool->setOption(Options::SIZE, mt_rand(1, 20));
+        });
+    }
+
+    $loop->addTimer(10, function () use ($pool, $timer, $loop) {
+        for ($i = 0; $i < I; $i++) {
+            echo $i, PHP_EOL;
+            $j = $i;
+            $pool->rpc(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::rpc('ping', [
+                'i' => $i,
+                's' => str_pad('', 512, '.'),
+            ]))->then(function ($data) use ($j) {
+                echo 'Answer for ' . $j . ' * ' . $j . ' * ' . $j . ' * ' . $j . ': ', $data['result'], PHP_EOL;
+            }, function ($error) {
+                var_export($error);
+                die();
+            });
+        }
+
+        $pool->rpc(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::rpc('ping', [
+            'i' => ++$i,
+        ]))->then(function () use ($pool, $timer, $loop) {
+            echo 'Terminating pool', PHP_EOL;
+            $pool->terminate(\WyriHaximus\React\ChildProcess\Messenger\Messages\Factory::message([
+                'woeufh209h838392',
+            ]));
+            $timer->cancel();
+            echo 'Done!!!', PHP_EOL;
+            $loop->stop();
+        });
+    });
+});
+
+$loop->run();
diff --git a/examples/ping-pong-set-options/pong.php b/examples/ping-pong-set-options/pong.php
new file mode 100644
index 0000000..9f8ea4d
--- /dev/null
+++ b/examples/ping-pong-set-options/pong.php
@@ -0,0 +1,41 @@
+<?php
+
+require dirname(dirname(__DIR__)) . '/vendor/autoload.php';
+
+use React\EventLoop\Factory;
+use React\Promise\Deferred;
+use WyriHaximus\React\ChildProcess\Messenger\Messages\Invoke;
+use WyriHaximus\React\ChildProcess\Messenger\Messages\Payload;
+use WyriHaximus\React\ChildProcess\Messenger\Messenger;
+use WyriHaximus\React\ChildProcess\Messenger\Recipient;
+
+$loop = Factory::create();
+
+$recipient = \WyriHaximus\React\ChildProcess\Messenger\Factory::child($loop);
+$recipient->on('message', function (Payload $payload, Messenger $messenger) {
+    $messenger->write(json_encode([
+        'type' => 'message',
+        'payload' => $payload,
+    ]));
+
+    $messenger->getLoop()->addTimer(1, function () use ($messenger) {
+        $messenger->getLoop()->stop();
+    });
+});
+$recipient->registerRpc('ping', function (Payload $payload, Messenger $messenger) use ($loop) {
+    $stopAt = time() + mt_rand(1, 2);
+
+    do {
+        // Don nothing
+    } while ($stopAt >= time());
+
+    /*$messenger->getLoop()->addTimer(1, function () use ($messenger) {
+        $messenger->getLoop()->stop();
+    });*/
+
+    return \React\Promise\resolve([
+        'result' => $payload['i'] * $payload['i'] * $payload['i'] * $payload['i'],
+    ]);
+});
+
+$loop->run();
diff --git a/src/Info.php b/src/Info.php
index 92a25bc..c015a57 100644
--- a/src/Info.php
+++ b/src/Info.php
@@ -4,9 +4,12 @@
 
 class Info
 {
-    const BUSY  = 'busy';
-    const CALLS = 'calls';
-    const IDLE  = 'idle';
-    const SIZE  = 'size';
-    const TOTAL = 'total';
+    const BUSY        = 'busy';
+    const CALLS       = 'calls';
+    const IDLE        = 'idle';
+    const SIZE        = 'size';
+    const STARTING    = 'starting';
+    const RUNNING     = 'running';
+    const TERMINATING = 'terminating';
+    const TOTAL       = 'total';
 }
diff --git a/src/Manager/Fixed.php b/src/Manager/Fixed.php
index b614aee..b737ebc 100644
--- a/src/Manager/Fixed.php
+++ b/src/Manager/Fixed.php
@@ -22,32 +22,81 @@ class Fixed implements ManagerInterface
      */
     protected $loop;
 
+    /**
+     * @var ProcessCollectionInterface
+     */
+    protected $processesCollection;
+
     /**
      * @var WorkerInterface[]
      */
     protected $workers = [];
 
+    /**
+     * @var array
+     */
+    protected $options;
+
+    /**
+     * @var int
+     */
+    protected $workerCount = 0;
+
+    /**
+     * @var int
+     */
+    protected $terminatingCount = 0;
+
+    /**
+     * @var int
+     */
+    protected $startingCount = 0;
+
     public function __construct(ProcessCollectionInterface $processCollection, LoopInterface $loop, array $options = [])
     {
+        $this->options = $options;
         $this->loop = $loop;
+        $this->processesCollection = $processCollection;
         $processCollection->rewind();
-        for ($i = 0; $i < $options[Options::SIZE]; $i++) {
-            $this->spawn($processCollection, $options);
+        $this->spawnWorkers($this->options[Options::SIZE]);
+    }
+
+    protected function spawnWorkers($count)
+    {
+        for ($i = 0; $i < $count; $i++) {
+            $this->spawn($this->processesCollection, $this->options);
         }
     }
 
     protected function spawn($processCollection, $options)
     {
-        $workerDone = function (WorkerInterface $worker) {
-            $this->workerAvailable($worker);
-        };
+        $this->startingCount++;
         $current = $processCollection->current();
         $promise = $current($this->loop, $options);
-        $promise->then(function (Messenger $messenger) use ($workerDone) {
+        $promise->then(function (Messenger $messenger) {
+            $this->startingCount--;
+            $this->workerCount++;
             $worker = new Worker($messenger);
-            $this->workers[] = $worker;
-            $worker->on('done', $workerDone);
+            $this->workers[spl_object_hash($worker)] = $worker;
+            $worker->on('done', function (WorkerInterface $worker) {
+                if ($this->workerCount + $this->startingCount > $this->options[Options::SIZE]) {
+                    $worker->terminate();
+                    return;
+                }
+
+                $this->workerAvailable($worker);
+            });
+            $worker->on('terminating', function (WorkerInterface $worker) {
+                unset($this->workers[spl_object_hash($worker)]);
+                $this->workerCount--;
+                $this->terminatingCount++;
+            });
+            $worker->on('terminated', function (WorkerInterface $worker) {
+                $this->terminatingCount--;
+            });
             $this->workerAvailable($worker);
+        }, function () {
+            $this->startingCount--;
         });
 
         $processCollection->next();
@@ -63,6 +112,10 @@ protected function workerAvailable(WorkerInterface $worker)
 
     public function ping()
     {
+        if ($this->workerCount + $this->startingCount < $this->options[Options::SIZE]) {
+            $this->spawnWorkers($this->options[Options::SIZE] - ($this->workerCount + $this->startingCount));
+        }
+
         foreach ($this->workers as $worker) {
             if (!$worker->isBusy()) {
                 $this->workerAvailable($worker);
@@ -90,17 +143,26 @@ public function terminate()
 
     public function info()
     {
-        $count = count($this->workers);
         $busy = 0;
         foreach ($this->workers as $worker) {
             if ($worker->isBusy()) {
                 $busy++;
             }
         }
+
         return [
-            Info::TOTAL => $count,
-            Info::BUSY => $busy,
-            Info::IDLE => $count - $busy,
+            Info::TOTAL       => $this->workerCount + $this->terminatingCount,
+            Info::STARTING    => $this->startingCount,
+            Info::RUNNING     => $this->workerCount,
+            Info::TERMINATING => $this->terminatingCount,
+            Info::BUSY        => $busy,
+            Info::IDLE        => $this->workerCount - $busy,
         ];
     }
+
+    public function setOptions(array $options)
+    {
+        $this->options = $options;
+        $this->ping();
+    }
 }
diff --git a/src/Manager/Flexible.php b/src/Manager/Flexible.php
index da7ff29..bfcaccf 100644
--- a/src/Manager/Flexible.php
+++ b/src/Manager/Flexible.php
@@ -6,6 +6,7 @@
 use React\EventLoop\LoopInterface;
 use WyriHaximus\React\ChildProcess\Messenger\Messages\Message;
 use WyriHaximus\React\ChildProcess\Messenger\Messenger;
+use WyriHaximus\React\ChildProcess\Pool\Info;
 use WyriHaximus\React\ChildProcess\Pool\ManagerInterface;
 use WyriHaximus\React\ChildProcess\Pool\Options;
 use WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface;
@@ -47,7 +48,17 @@ class Flexible implements ManagerInterface
     /**
      * @var int
      */
-    protected $startingProcesses = 0;
+    protected $workerCount = 0;
+
+    /**
+     * @var int
+     */
+    protected $terminatingCount = 0;
+
+    /**
+     * @var int
+     */
+    protected $startingCount = 0;
 
     public function __construct(ProcessCollectionInterface $processCollection, LoopInterface $loop, array $options = [])
     {
@@ -67,25 +78,28 @@ protected function workerAvailable(WorkerInterface $worker)
 
     protected function spawn()
     {
-        $this->startingProcesses++;
+        $this->startingCount++;
         $current = $this->processCollection->current();
         $promise = $current($this->loop, $this->options);
         $promise->then(function (Messenger $messenger) {
+            $this->startingCount--;
+            $this->workerCount++;
             $worker = new Worker($messenger);
-            $this->workers[] = $worker;
+            $this->workers[spl_object_hash($worker)] = $worker;
             $worker->on('done', function (WorkerInterface $worker) {
                 $this->workerAvailable($worker);
             });
             $worker->on('terminating', function (WorkerInterface $worker) {
-                foreach ($this->workers as $key => $value) {
-                    if ($worker === $value) {
-                        unset($this->workers[$key]);
-                        break;
-                    }
-                }
+                unset($this->workers[spl_object_hash($worker)]);
+                $this->workerCount--;
+                $this->terminatingCount++;
+            });
+            $worker->on('terminated', function (WorkerInterface $worker) {
+                $this->terminatingCount--;
             });
             $this->workerAvailable($worker);
-            $this->startingProcesses--;
+        }, function () {
+            $this->startingCount--;
         });
 
         $this->processCollection->next();
@@ -103,12 +117,12 @@ public function ping()
             }
         }
 
-        if (count($this->workers) + $this->startingProcesses < $this->options[Options::MIN_SIZE]) {
+        if ($this->workerCount + $this->startingCount < $this->options[Options::MIN_SIZE]) {
             $this->spawn();
             return;
         }
 
-        if (count($this->workers) + $this->startingProcesses < $this->options[Options::MAX_SIZE]) {
+        if ($this->workerCount + $this->startingCount < $this->options[Options::MAX_SIZE]) {
             $this->spawn();
         }
     }
@@ -133,17 +147,25 @@ public function terminate()
 
     public function info()
     {
-        $count = count($this->workers);
         $busy = 0;
         foreach ($this->workers as $worker) {
             if ($worker->isBusy()) {
                 $busy++;
             }
         }
+
         return [
-            'total' => $count,
-            'busy' => $busy,
-            'idle' => $count - $busy,
+            Info::TOTAL       => $this->workerCount + $this->terminatingCount,
+            Info::STARTING    => $this->startingCount,
+            Info::RUNNING     => $this->workerCount,
+            Info::TERMINATING => $this->terminatingCount,
+            Info::BUSY        => $busy,
+            Info::IDLE        => $this->workerCount - $busy,
         ];
     }
+
+    public function setOptions(array $options)
+    {
+        $this->options = $options;
+    }
 }
diff --git a/src/ManagerInterface.php b/src/ManagerInterface.php
index 97778f7..a2a2dc7 100644
--- a/src/ManagerInterface.php
+++ b/src/ManagerInterface.php
@@ -51,4 +51,12 @@ public function message(Message $message);
      * @return array
      */
     public function info();
+
+    /**
+     * Overwrite the current options
+     *
+     * @param array $options
+     * @return void
+     */
+    public function setOptions(array $options);
 }
diff --git a/src/Pool/Dummy.php b/src/Pool/Dummy.php
index bd948b8..727e14f 100644
--- a/src/Pool/Dummy.php
+++ b/src/Pool/Dummy.php
@@ -56,4 +56,8 @@ public function info()
     {
         return [];
     }
+
+    public function setOption($key, $value)
+    {
+    }
 }
diff --git a/src/Pool/Fixed.php b/src/Pool/Fixed.php
index be7345b..2a973da 100644
--- a/src/Pool/Fixed.php
+++ b/src/Pool/Fixed.php
@@ -122,12 +122,20 @@ public function terminate(Message $message = null, $timeout = 5, $signal = null)
      */
     public function info()
     {
-        $workers = $this->manager->info();
-        return [
-            Info::BUSY  => $workers[Info::BUSY],
-            Info::CALLS => $this->queue->count(),
-            Info::IDLE  => $workers[Info::IDLE],
-            Info::SIZE  => $workers[Info::TOTAL],
-        ];
+        $info = $this->manager->info();
+        $info[Info::CALLS] = $this->queue->count();
+        return $info;
+    }
+
+    /**
+     * Override option
+     *
+     * @param $key
+     * @param $value
+     */
+    public function setOption($key, $value)
+    {
+        $this->options[$key] = $value;
+        $this->manager->setOptions($this->options);
     }
 }
diff --git a/src/Pool/Flexible.php b/src/Pool/Flexible.php
index 75947bb..b20a976 100644
--- a/src/Pool/Flexible.php
+++ b/src/Pool/Flexible.php
@@ -153,12 +153,20 @@ public function terminate(Message $message = null, $timeout = 5, $signal = null)
      */
     public function info()
     {
-        $workers = $this->manager->info();
-        return [
-            Info::BUSY  => $workers[Info::BUSY],
-            Info::CALLS => $this->queue->count(),
-            Info::IDLE  => $workers[Info::IDLE],
-            Info::SIZE  => $workers[Info::TOTAL],
-        ];
+        $info = $this->manager->info();
+        $info[Info::CALLS] = $this->queue->count();
+        return $info;
+    }
+
+    /**
+     * Override option
+     *
+     * @param $key
+     * @param $value
+     */
+    public function setOption($key, $value)
+    {
+        $this->options[$key] = $value;
+        $this->manager->setOptions($this->options);
     }
 }
diff --git a/src/PoolInterface.php b/src/PoolInterface.php
index 5cda7d8..0eca59a 100644
--- a/src/PoolInterface.php
+++ b/src/PoolInterface.php
@@ -43,4 +43,12 @@ public function message(Message $message);
      * @return mixed
      */
     public function terminate(Message $message, $timeout = 5, $signal = null);
+
+    /**
+     * Override option
+     *
+     * @param $key
+     * @param $value
+     */
+    public function setOption($key, $value);
 }
diff --git a/src/Worker.php b/src/Worker.php
index e8aca94..8c06ce0 100644
--- a/src/Worker.php
+++ b/src/Worker.php
@@ -22,6 +22,11 @@ class Worker implements WorkerInterface
      */
     protected $busy = false;
 
+    /**
+     * @var bool
+     */
+    protected $terminating = false;
+
     /**
      * @param Messenger $messenger
      */
@@ -59,13 +64,26 @@ public function isBusy()
         return $this->busy;
     }
 
+    /**
+     * @return bool
+     */
+    public function isTerminating()
+    {
+        return $this->terminating;
+    }
+
     /*
      * @return PromiseInterface
      */
     public function terminate()
     {
+        $this->terminating = true;
         $this->busy = true;
         $this->emit('terminating', [$this]);
-        return $this->messenger->softTerminate();
+        $promise = $this->messenger->softTerminate();
+        $promise->always(function () {
+            $this->emit('terminated', [$this]);
+        });
+        return $promise;
     }
 }
diff --git a/src/WorkerInterface.php b/src/WorkerInterface.php
index 9f489c3..2c31cf4 100644
--- a/src/WorkerInterface.php
+++ b/src/WorkerInterface.php
@@ -31,6 +31,11 @@ public function message(Message $message);
      */
     public function isBusy();
 
+    /**
+     * @return bool
+     */
+    public function isTerminating();
+
     /**
      * @return PromiseInterface
      */
diff --git a/tests/FunctionsTest.php b/tests/FunctionsTest.php
index 2c0566e..be6dadf 100644
--- a/tests/FunctionsTest.php
+++ b/tests/FunctionsTest.php
@@ -125,17 +125,19 @@ public function testGetQueue($options, $default, $loop, $output)
 
     public function providerGetManager()
     {
+        $processCollection = Phake::mock('WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface');
+
         $r = [];
 
         $r[] = [
             [
                 Options::SIZE => 0,
             ],
-            Phake::mock('WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface'),
+            $processCollection,
             'WyriHaximus\React\ChildProcess\Pool\Manager\Fixed',
             Factory::create(),
             new Fixed(
-                Phake::mock('WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface'),
+                $processCollection,
                 Factory::create(),
                 [
                     Options::SIZE => 0,
@@ -149,13 +151,12 @@ public function providerGetManager()
                 Options::MANAGER => $mock,
                 Options::SIZE => 0,
             ],
-            Phake::mock('WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface'),
+            $processCollection,
             'WyriHaximus\React\ChildProcess\Pool\Queue\Memory',
             Factory::create(),
             $mock,
         ];
 
-        $processCollection = Phake::mock('WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface');
         $r[] = [
             [
                 Options::MANAGER => new Flexible(
@@ -168,7 +169,7 @@ public function providerGetManager()
                 ),
                 Options::SIZE => 0,
             ],
-            Phake::mock('WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface'),
+            $processCollection,
             'WyriHaximus\React\ChildProcess\Pool\Queue\Memory',
             Factory::create(),
             new Flexible(
diff --git a/tests/Manager/FixedTest.php b/tests/Manager/FixedTest.php
index d12ef8e..a34f5b6 100644
--- a/tests/Manager/FixedTest.php
+++ b/tests/Manager/FixedTest.php
@@ -72,6 +72,9 @@ public function testInfoAtStart()
 
         $this->assertSame([
             Info::TOTAL => 0,
+            Info::STARTING => 0,
+            Info::RUNNING => 0,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 0,
         ], $this->manager->info());
@@ -122,6 +125,9 @@ public function testRpc()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
@@ -130,6 +136,9 @@ public function testRpc()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 1,
             Info::IDLE => 0,
         ], $this->manager->info());
@@ -138,6 +147,9 @@ public function testRpc()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
@@ -145,9 +157,11 @@ public function testRpc()
 
     public function testTerminate()
     {
+        $terminateDeferred = new Deferred();
         $workerDeferred = new Deferred();
         $worker = null;
         $messenger = Phake::mock('WyriHaximus\React\ChildProcess\Messenger\Messenger');
+        Phake::when($messenger)->softTerminate()->thenReturn($terminateDeferred->promise());
 
         Phake::when($this->processCollection)->current()->thenReturnCallback(function () use ($workerDeferred) {
             return function () use ($workerDeferred) {
@@ -165,11 +179,15 @@ public function testTerminate()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
 
         $emittedTerminate = false;
+
         $worker->on('terminating', function ($worker) use (&$emittedTerminate) {
             $this->assertInstanceOf('WyriHaximus\React\ChildProcess\Pool\WorkerInterface', $worker);
             $emittedTerminate = true;
@@ -179,7 +197,21 @@ public function testTerminate()
 
         $this->assertSame([
             Info::TOTAL => 1,
-            Info::BUSY => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 0,
+            Info::TERMINATING => 1,
+            Info::BUSY => 0,
+            Info::IDLE => 0,
+        ], $this->manager->info());
+
+        $terminateDeferred->resolve();
+
+        $this->assertSame([
+            Info::TOTAL => 0,
+            Info::STARTING => 0,
+            Info::RUNNING => 0,
+            Info::TERMINATING => 0,
+            Info::BUSY => 0,
             Info::IDLE => 0,
         ], $this->manager->info());
 
@@ -211,4 +243,16 @@ public function testMessage()
 
         Phake::verify($messenger)->message($message);
     }
+
+    public function testSetOptions()
+    {
+        Phake::when($this->processCollection)->current()->thenReturn(function () {
+            return \React\Promise\resolve(
+                Phake::mock('WyriHaximus\React\ChildProcess\Messenger\Messenger')
+            );
+        });
+        $this->manager = new Fixed($this->processCollection, $this->loop, [
+            Options::SIZE => 1,
+        ]);
+    }
 }
diff --git a/tests/Manager/FlexibleTest.php b/tests/Manager/FlexibleTest.php
index 858e524..eaba871 100644
--- a/tests/Manager/FlexibleTest.php
+++ b/tests/Manager/FlexibleTest.php
@@ -72,6 +72,9 @@ public function testInfoAtStart()
 
         $this->assertSame([
             Info::TOTAL => 0,
+            Info::STARTING => 0,
+            Info::RUNNING => 0,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 0,
         ], $this->manager->info());
@@ -122,6 +125,9 @@ public function testRpc()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
@@ -130,6 +136,9 @@ public function testRpc()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
@@ -138,6 +147,9 @@ public function testRpc()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 1,
             Info::IDLE => 0,
         ], $this->manager->info());
@@ -146,6 +158,9 @@ public function testRpc()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
@@ -153,9 +168,11 @@ public function testRpc()
 
     public function testTerminate()
     {
+        $terminateDeferred = new Deferred();
         $workerDeferred = new Deferred();
         $worker = null;
         $messenger = Phake::mock('WyriHaximus\React\ChildProcess\Messenger\Messenger');
+        Phake::when($messenger)->softTerminate()->thenReturn($terminateDeferred->promise());
 
         Phake::when($this->processCollection)->current()->thenReturnCallback(function () use ($workerDeferred) {
             return function () use ($workerDeferred) {
@@ -173,6 +190,9 @@ public function testTerminate()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
@@ -181,6 +201,9 @@ public function testTerminate()
 
         $this->assertSame([
             Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 1,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 1,
         ], $this->manager->info());
@@ -193,8 +216,22 @@ public function testTerminate()
 
         $this->manager->terminate();
 
+        $this->assertSame([
+            Info::TOTAL => 1,
+            Info::STARTING => 0,
+            Info::RUNNING => 0,
+            Info::TERMINATING => 1,
+            Info::BUSY => 0,
+            Info::IDLE => 0,
+        ], $this->manager->info());
+
+        $terminateDeferred->resolve();
+
         $this->assertSame([
             Info::TOTAL => 0,
+            Info::STARTING => 0,
+            Info::RUNNING => 0,
+            Info::TERMINATING => 0,
             Info::BUSY => 0,
             Info::IDLE => 0,
         ], $this->manager->info());
@@ -207,6 +244,7 @@ public function testPingWorkerAvailable()
     {
         $rpc = Factory::rpc('foo', ['bar']);
         $messenger = Phake::mock('WyriHaximus\React\ChildProcess\Messenger\Messenger');
+        Phake::when($messenger)->softTerminate()->thenReturn(new FulfilledPromise());
         Phake::when($messenger)->rpc($rpc)->thenReturn((new Deferred())->promise());
         $loop = Phake::mock('React\EventLoop\LoopInterface');
         $processCollection = Phake::mock('WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface');
diff --git a/tests/Pool/FixedTest.php b/tests/Pool/FixedTest.php
index 0db9afc..36e5624 100644
--- a/tests/Pool/FixedTest.php
+++ b/tests/Pool/FixedTest.php
@@ -3,10 +3,13 @@
 namespace WyriHaximus\React\Tests\ChildProcess\Pool\Pool;
 
 use Phake;
+use React\EventLoop\Factory as LoopFactory;
 use WyriHaximus\React\ChildProcess\Messenger\Messages\Factory;
 use WyriHaximus\React\ChildProcess\Pool\Info;
 use WyriHaximus\React\ChildProcess\Pool\Options;
 use WyriHaximus\React\ChildProcess\Pool\Factory\Fixed;
+use WyriHaximus\React\ChildProcess\Pool\Pool\Fixed as FixedPool;
+use WyriHaximus\React\ChildProcess\Pool\ProcessCollection\Single;
 use WyriHaximus\React\Tests\ChildProcess\Pool\TestCase;
 
 class FixedTest extends TestCase
@@ -67,10 +70,10 @@ public function testInfo()
         $this->assertTrue($promiseHasResolved);
 
         $this->assertSame([
+            Info::TOTAL => 1,
+            Info::IDLE  => 2,
             Info::BUSY  => 3,
             Info::CALLS => 4,
-            Info::IDLE  => 2,
-            Info::SIZE  => 1,
         ], $poolInstance->info());
     }
 
@@ -140,4 +143,32 @@ public function testManagerReady()
 
         Phake::verify($worker)->rpc($message);
     }
+
+    public function testSetOption()
+    {
+        $manager = Phake::mock('WyriHaximus\React\ChildProcess\Pool\Manager\Fixed');
+        $options = [
+            Options::SIZE => 1337,
+            Options::MANAGER => $manager,
+        ];
+        $loop = LoopFactory::create();
+        $processCollection = new Single(function () {
+            return Phake::mock('React\ChildProcess\Process');
+        });
+        $pool = new FixedPool($processCollection, $loop, $options);
+        $pool->setOption('key', 'value');
+        $pool->setOption(Options::SIZE, 128);
+        Phake::inOrder(
+            Phake::verify($manager)->setOptions([
+                'key' => 'value',
+                Options::SIZE => 1337,
+                Options::MANAGER => $manager,
+            ]),
+            Phake::verify($manager)->setOptions([
+                'key' => 'value',
+                Options::SIZE => 128,
+                Options::MANAGER => $manager,
+            ])
+        );
+    }
 }
diff --git a/tests/Pool/FlexibleTest.php b/tests/Pool/FlexibleTest.php
index 79f34ad..1bb2ad7 100644
--- a/tests/Pool/FlexibleTest.php
+++ b/tests/Pool/FlexibleTest.php
@@ -3,10 +3,13 @@
 namespace WyriHaximus\React\Tests\ChildProcess\Pool\Pool;
 
 use Phake;
+use React\EventLoop\Factory as LoopFactory;
 use WyriHaximus\React\ChildProcess\Messenger\Messages\Factory;
 use WyriHaximus\React\ChildProcess\Pool\Info;
 use WyriHaximus\React\ChildProcess\Pool\Options;
 use WyriHaximus\React\ChildProcess\Pool\Factory\Flexible;
+use WyriHaximus\React\ChildProcess\Pool\Pool\Flexible as FlexiblePool;
+use WyriHaximus\React\ChildProcess\Pool\ProcessCollection\Single;
 use WyriHaximus\React\Tests\ChildProcess\Pool\TestCase;
 
 class FlexibleTest extends TestCase
@@ -67,10 +70,10 @@ public function testInfo()
         $this->assertTrue($promiseHasResolved);
 
         $this->assertSame([
+            Info::TOTAL => 1,
+            Info::IDLE  => 2,
             Info::BUSY  => 3,
             Info::CALLS => 4,
-            Info::IDLE  => 2,
-            Info::SIZE  => 1,
         ], $poolInstance->info());
     }
 
@@ -240,4 +243,32 @@ public function testManagerReadyQueueEmptyIsBusy()
 
         Phake::verify($timer)->cancel();
     }
+
+    public function testSetOption()
+    {
+        $manager = Phake::mock('WyriHaximus\React\ChildProcess\Pool\Manager\Fixed');
+        $options = [
+            Options::SIZE => 1337,
+            Options::MANAGER => $manager,
+        ];
+        $loop = LoopFactory::create();
+        $processCollection = new Single(function () {
+            return Phake::mock('React\ChildProcess\Process');
+        });
+        $pool = new FlexiblePool($processCollection, $loop, $options);
+        $pool->setOption('key', 'value');
+        $pool->setOption(Options::SIZE, 128);
+        Phake::inOrder(
+            Phake::verify($manager)->setOptions([
+                'key' => 'value',
+                Options::SIZE => 1337,
+                Options::MANAGER => $manager,
+            ]),
+            Phake::verify($manager)->setOptions([
+                'key' => 'value',
+                Options::SIZE => 128,
+                Options::MANAGER => $manager,
+            ])
+        );
+    }
 }
diff --git a/tests/WorkerTest.php b/tests/WorkerTest.php
index 7edb9eb..05cd600 100644
--- a/tests/WorkerTest.php
+++ b/tests/WorkerTest.php
@@ -13,6 +13,7 @@ class WorkerTest extends TestCase
     public function testWorker()
     {
         $messenger = Phake::mock('WyriHaximus\React\ChildProcess\Messenger\Messenger');
+        Phake::when($messenger)->softTerminate()->thenReturn(new FulfilledPromise());
         $worker = new Worker($messenger);
 
         $this->assertFalse($worker->isBusy());
@@ -53,4 +54,17 @@ public function testMessage()
         $worker->message($message);
         Phake::verify($messenger)->message($message);
     }
+
+    public function testTerminate()
+    {
+        $messenger = Phake::mock('WyriHaximus\React\ChildProcess\Messenger\Messenger');
+        Phake::when($messenger)->softTerminate()->thenReturn(new FulfilledPromise());
+        $worker = new Worker($messenger);
+
+        $this->assertFalse($worker->isBusy());
+        $this->assertFalse($worker->isTerminating());
+        $worker->terminate();
+        $this->assertTrue($worker->isBusy());
+        $this->assertTrue($worker->isTerminating());
+    }
 }