diff --git a/examples/exec.php b/examples/exec-inspect.php
similarity index 64%
rename from examples/exec.php
rename to examples/exec-inspect.php
index b9d9f78..a7d40e3 100644
--- a/examples/exec.php
+++ b/examples/exec-inspect.php
@@ -5,25 +5,32 @@
 
 use React\EventLoop\Factory as LoopFactory;
 use Clue\React\Docker\Factory;
-use Clue\React\Docker\ExecHelper;
-use React\Stream\Stream;
 use Clue\React\Buzz\Message\ResponseException;
 
-$container = isset($argv[1]) ? $argv[1] : 'asd';
+$container = 'asd';
+//$cmd = array('echo', 'hello world');
+//$cmd = array('sleep', '2');
+$cmd = array('sh', '-c', 'echo -n hello && sleep 1 && echo world && sleep 1 && env');
+//$cmd = array('cat', 'invalid-path');
+
+if (isset($argv[1])) {
+    $container = $argv[1];
+    $cmd = array_slice($argv, 2);
+}
 
 $loop = LoopFactory::create();
 
 $factory = new Factory($loop);
 $client = $factory->createClient();
 
-$client->execCreate($container, array('Cmd' => array('sleep', '2'), 'AttachStdout' => true))->then(function ($info) use ($client) {
+$client->execCreate($container, array('Cmd' => $cmd, 'AttachStdout' => true, 'AttachStderr' => true, 'Tty' => true))->then(function ($info) use ($client) {
     echo 'Created with info: ' . json_encode($info) . PHP_EOL;
 
     return $client->execInspect($info['Id']);
 })->then(function ($info) use ($client) {
     echo 'Inspected after creation: ' . json_encode($info, JSON_PRETTY_PRINT) . PHP_EOL;
 
-    return $client->execStart($info['ID'], array())->then(function ($out) use ($client, $info) {
+    return $client->execStart($info['ID'], array('Tty' => true))->then(function ($out) use ($client, $info) {
         echo 'Starting returned: ';
         var_dump($out);
 
diff --git a/src/Client.php b/src/Client.php
index b511a4a..eebb8ca 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -903,15 +903,20 @@ public function execCreate($container, $config)
     /**
      * Starts a previously set up exec instance id.
      *
+     * This resolves with a string of the command output, i.e. STDOUT and STDERR
+     * as set up in the `execCreate()` call.
+     *
+     * Keep in mind that this means the whole string has to be kept in memory.
+     *
      * If detach is true, this API returns after starting the exec command.
      * Otherwise, this API sets up an interactive session with the exec command.
      *
      * @param string $exec   exec ID
      * @param array  $config (see link)
-     * @return PromiseInterface Promise<array> stream of message objects
+     * @return PromiseInterface Promise<string> buffered exec data
      * @link https://docs.docker.com/reference/api/docker_remote_api_v1.15/#exec-start
      */
-    public function execStart($exec, $config)
+    public function execStart($exec, $config = array())
     {
         return $this->postJson(
             $this->uri->expand(
@@ -921,7 +926,7 @@ public function execStart($exec, $config)
                 )
             ),
             $config
-        )->then(array($this->parser, 'expectJson'));
+        )->then(array($this->parser, 'expectPlain'));
     }
 
     /**
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index 146829a..821393d 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -386,11 +386,11 @@ public function testExecCreate()
 
     public function testExecStart()
     {
-        $json = array();
+        $data = 'hello world';
         $config = array();
-        $this->expectRequestFlow('post', '/exec/123/start', $this->createResponseJson($json), 'expectJson');
+        $this->expectRequestFlow('post', '/exec/123/start', $this->createResponse($data), 'expectPlain');
 
-        $this->expectPromiseResolveWith($json, $this->client->execStart(123, $config));
+        $this->expectPromiseResolveWith($data, $this->client->execStart(123, $config));
     }
 
     public function testExecResize()
diff --git a/tests/FunctionalClientTest.php b/tests/FunctionalClientTest.php
index 6111d38..39fa090 100644
--- a/tests/FunctionalClientTest.php
+++ b/tests/FunctionalClientTest.php
@@ -72,6 +72,103 @@ public function testCreateStartAndRemoveContainer()
         $this->assertEquals('destroy', $ret[3]['status']);
     }
 
+    public function testStartRunning()
+    {
+        $config = array(
+            'Image' => 'busybox',
+            'Tty' => true,
+            'Cmd' => array('sleep', '10')
+        );
+
+        $promise = $this->client->containerCreate($config);
+        $container = Block\await($promise, $this->loop);
+
+        $this->assertNotNull($container['Id']);
+        $this->assertNull($container['Warnings']);
+
+        $start = microtime(true);
+
+        $promise = $this->client->containerStart($container['Id']);
+        $ret = Block\await($promise, $this->loop);
+
+        $this->assertEquals('', $ret);
+
+        return $container['Id'];
+    }
+
+    /**
+     * @depends testStartRunning
+     * @param string $container
+     * @return string
+     */
+    public function testExecCreateWhileRunning($container)
+    {
+        $promise = $this->client->execCreate($container, array(
+            'Cmd' => array('echo', '-n', 'hello', 'world'),
+            'AttachStdout' => true,
+            'AttachStderr' => true,
+            'Tty' => true
+        ));
+        $exec = Block\await($promise, $this->loop);
+
+        $this->assertTrue(is_array($exec));
+        $this->assertTrue(is_string($exec['Id']));
+
+        return $exec['Id'];
+    }
+
+    /**
+     * @depends testExecCreateWhileRunning
+     * @param string $exec
+     */
+    public function testExecInspectBeforeRunning($exec)
+    {
+        $promise = $this->client->execInspect($exec);
+        $info = Block\await($promise, $this->loop);
+
+        $this->assertTrue(is_array($info));
+        $this->assertFalse($info['Running']);
+        $this->assertEquals(null, $info['ExitCode']);
+    }
+
+    /**
+     * @depends testExecCreateWhileRunning
+     * @param string $exec
+     */
+    public function testExecStartWhileRunning($exec)
+    {
+        $promise = $this->client->execStart($exec, array('Tty' => true));
+        $output = Block\await($promise, $this->loop);
+
+        $this->assertEquals('hello world', $output);
+    }
+
+    /**
+     * @depends testExecCreateWhileRunning
+     * @param string $exec
+     */
+    public function testExecInspectAfterRunning($exec)
+    {
+        $promise = $this->client->execInspect($exec);
+        $info = Block\await($promise, $this->loop);
+
+        $this->assertTrue(is_array($info));
+        $this->assertFalse($info['Running']);
+        $this->assertEquals(0, $info['ExitCode']);
+    }
+
+    /**
+     * @depends testStartRunning
+     * @param string $container
+     */
+    public function testRemoveRunning($container)
+    {
+        $promise = $this->client->containerRemove($container, true, true);
+        $ret = Block\await($promise, $this->loop);
+
+        $this->assertEquals('', $ret);
+    }
+
     /**
      * @expectedException RuntimeException
      */