diff --git a/composer.json b/composer.json
index 735951e..dadb43a 100644
--- a/composer.json
+++ b/composer.json
@@ -16,6 +16,9 @@
         "react/event-loop": "~0.4.0|~0.3.0",
         "react/child-process": "~0.4.0|~0.3.0"
     },
+    "require-dev": {
+        "clue/block-react": "^1.1"
+    },
     "autoload": {
         "psr-4": { "Clue\\React\\Zenity\\": "src/" }
     }
diff --git a/src/Zen/BaseZen.php b/src/Zen/BaseZen.php
index 55b6bb6..104a002 100644
--- a/src/Zen/BaseZen.php
+++ b/src/Zen/BaseZen.php
@@ -51,10 +51,16 @@ public function promise()
 
     public function close()
     {
+        // resolve with whatever is currently buffered
         $this->deferred->resolve();
 
         if ($this->process !== null && $this->process->isRunning()) {
             $this->process->terminate(SIGKILL);
+
+            // explicitly close all streams immediately
+            $this->process->stdin->close();
+            $this->process->stdout->close();
+            $this->process->stderr->close();
         }
 
         return $this;
diff --git a/tests/FunctionalLauncherTest.php b/tests/FunctionalLauncherTest.php
index 27fc22a..614de24 100644
--- a/tests/FunctionalLauncherTest.php
+++ b/tests/FunctionalLauncherTest.php
@@ -1,10 +1,11 @@
 <?php
 
+use Clue\React\Block;
 use Clue\React\Zenity\Launcher;
-use React\EventLoop\Factory;
 use Clue\React\Zenity\Zen\BaseZen;
+use React\EventLoop\Factory;
 
-class LauncherTest extends TestCase
+class FunctionalLauncherTest extends TestCase
 {
     private $loop;
     private $dialog;
@@ -27,9 +28,9 @@ public function testEchoParameters()
 
         $promise = $this->launcher->launch($this->dialog);
 
-        $this->loop->run();
+        $result = Block\await($promise, $this->loop, 1.0);
 
-        $promise->then($this->expectCallableOnceWith('--hello --world'));
+        $this->assertEquals('--hello --world', $result);
     }
 
     public function testDoesPassStdin()
@@ -44,9 +45,9 @@ public function testDoesPassStdin()
             $zen->close();
         });
 
-        $this->loop->run();
+        $result = Block\await($zen->promise(), $this->loop, 1.0);
 
-        $zen->promise()->then($this->expectCallableOnceWith('okay'));
+        $this->assertEquals('okay', $result);
     }
 
     public function testWaitForOutput()
diff --git a/tests/Zen/BaseZenTest.php b/tests/Zen/BaseZenTest.php
index 7a48406..596d281 100644
--- a/tests/Zen/BaseZenTest.php
+++ b/tests/Zen/BaseZenTest.php
@@ -22,6 +22,7 @@ public function setUp()
         $this->process->stdin = $this->instream;
 
         $this->process->stdout = $this->getMock('React\Stream\ReadableStreamInterface');
+        $this->process->stderr = $this->getMock('React\Stream\ReadableStreamInterface');
     }
 
     public function testClosingZenTerminatesProcess()
diff --git a/tests/Zen/FunctionalBaseZenTest.php b/tests/Zen/FunctionalBaseZenTest.php
index fb13a49..06236b7 100644
--- a/tests/Zen/FunctionalBaseZenTest.php
+++ b/tests/Zen/FunctionalBaseZenTest.php
@@ -1,8 +1,10 @@
 <?php
 
+use Clue\React\Block;
+use Clue\React\Zenity\Zen\BaseZen;
 use React\EventLoop\Factory;
 use React\ChildProcess\Process;
-use Clue\React\Zenity\Zen\BaseZen;
+
 class FunctionalBaseZenTest extends TestCase
 {
     public function setUp()
@@ -18,9 +20,9 @@ public function testZenResolvesWithProcessOutput()
         $zen = new BaseZen();
         $zen->go($process);
 
-        $this->loop->run();
+        $result = Block\await($zen->promise(), $this->loop, 1.0);
 
-        $zen->promise()->then($this->expectCallableOnceWith('okay'));
+        $this->assertEquals('okay', $result);
     }
 
     public function testZenResolvesWithTrueWhenProcessHasNoOutput()
@@ -31,9 +33,9 @@ public function testZenResolvesWithTrueWhenProcessHasNoOutput()
         $zen = new BaseZen();
         $zen->go($process);
 
-        $this->loop->run();
+        $result = Block\await($zen->promise(), $this->loop, 1.0);
 
-        $zen->promise()->then($this->expectCallableOnceWith(true));
+        $this->assertTrue($result);
     }
 
     public function testZenRejectsWhenProcessReturnsError()
@@ -44,9 +46,7 @@ public function testZenRejectsWhenProcessReturnsError()
         $zen = new BaseZen();
         $zen->go($process);
 
-        $this->loop->run();
-
-        $zen->promise()->then(null, $this->expectCallableOnceWith(1));
+        Block\await($zen->promise()->then(null, $this->expectCallableOnceWith(1)), $this->loop, 1.0);
     }
 
     public function testClosingZenResolvesWithOutputSoFar()
@@ -61,9 +61,9 @@ public function testClosingZenResolvesWithOutputSoFar()
             $zen->close();
         });
 
-        $this->loop->run();
+        $result = Block\await($zen->promise(), $this->loop, 1.0);
 
-        $zen->promise()->then($this->expectCallableOnceWith('okay'));
+        $this->assertEquals('okay', $result);
     }
 
     public function testTerminatingProcessReturnsError()
@@ -76,10 +76,9 @@ public function testTerminatingProcessReturnsError()
 
         $this->loop->addTimer(0.1, function() use ($process) {
             $process->terminate(SIGKILL);
+            $process->stdin->end();
         });
 
-        $this->loop->run();
-
-        $zen->promise()->then(null, $this->expectCallableOnce());
+        Block\await($zen->promise()->then(null, $this->expectCallableOnce()), $this->loop, 1.0);
     }
 }