Test the error coming from the pool is pickup and passed up through the promises to the callee, via @clue at #25 (comment)

Author: WyriHaximus

tests/ChildProcess/AdapterTest.php

@@ -2,6 +2,7 @@
 
 namespace React\Tests\Filesystem\ChildProcess;
 
+use React\EventLoop\Factory;
 use React\Filesystem\ChildProcess\Adapter;
 use React\Filesystem\Filesystem;
 use React\Filesystem\Node\NodeInterface;
@@ -324,4 +325,17 @@ public function testLs()
         ]);
         $this->assertTrue($calledOnData);
     }
+
+    public function testErrorFromPool()
+    {
+        $this->setExpectedException('\Exception', 'oops');
+
+        $loop = Factory::create();
+        $adapter = new Adapter($loop, [
+            'pool' => [
+                'class' => 'React\Tests\Filesystem\ChildProcess\PoolRpcErrorMockFactory',
+            ],
+        ]);
+        $this->await($adapter->touch('foo.bar'), $loop, 1);
+    }
 }

tests/ChildProcess/PoolRpcErrorMock.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace React\Tests\Filesystem\ChildProcess;
+
+use Evenement\EventEmitter;
+use React\EventLoop\LoopInterface;
+use React\Promise\FulfilledPromise;
+use React\Promise\RejectedPromise;
+use WyriHaximus\React\ChildProcess\Messenger\Messages\Message;
+use WyriHaximus\React\ChildProcess\Messenger\Messages\Rpc;
+use WyriHaximus\React\ChildProcess\Pool\PoolInterface;
+use WyriHaximus\React\ChildProcess\Pool\ProcessCollectionInterface;
+
+final class PoolRpcErrorMock extends EventEmitter implements PoolInterface
+{
+    public function __construct(ProcessCollectionInterface $processCollection, LoopInterface $loop, array $options = [])
+    {
+        // void
+    }
+
+    public function rpc(Rpc $message)
+    {
+        return new RejectedPromise([
+            'error' => [
+                'message' => 'oops',
+            ],
+        ]);
+    }
+
+    public function message(Message $message)
+    {
+        return new FulfilledPromise();
+    }
+
+    public function terminate(Message $message, $timeout = 5, $signal = null)
+    {
+        return new FulfilledPromise();
+    }
+
+    public function info()
+    {
+        return [];
+    }
+}

tests/ChildProcess/PoolRpcErrorMockFactory.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace React\Tests\Filesystem\ChildProcess;
+
+use React\ChildProcess\Process;
+use React\EventLoop\Factory;
+use React\EventLoop\LoopInterface;
+use React\Promise\FulfilledPromise;
+use WyriHaximus\React\ChildProcess\Pool\PoolFactoryInterface;
+use WyriHaximus\React\ChildProcess\Pool\ProcessCollection\Single;
+
+final class PoolRpcErrorMockFactory implements PoolFactoryInterface
+{
+    public static function create(Process $childProcess, LoopInterface $loop, array $options = [])
+    {
+        return new FulfilledPromise(new PoolRpcErrorMock(
+            new Single(function () {}),
+            Factory::create(),
+            []
+        ));
+    }
+
+    public static function createFromClass($class, LoopInterface $loop, array $options = [])
+    {
+        return new FulfilledPromise(new PoolRpcErrorMock(
+            new Single(function () {}),
+            Factory::create(),
+            []
+        ));
+    }
+
+}