diff --git a/bin/windows/ProcessWrapper.exe b/bin/windows/ProcessWrapper.exe
index df431cc..e7a7b71 100644
Binary files a/bin/windows/ProcessWrapper.exe and b/bin/windows/ProcessWrapper.exe differ
diff --git a/bin/windows/ProcessWrapper64.exe b/bin/windows/ProcessWrapper64.exe
index ffd0dc5..bf912c3 100644
Binary files a/bin/windows/ProcessWrapper64.exe and b/bin/windows/ProcessWrapper64.exe differ
diff --git a/examples/basic-command.php b/examples/basic-command.php
index 09c2b72..86761e9 100644
--- a/examples/basic-command.php
+++ b/examples/basic-command.php
@@ -6,7 +6,11 @@ use Amp\ByteStream\Message;
 use Amp\Process\Process;
 
 Amp\Loop::run(function () {
-    $process = yield Process::start("echo 'Hello, world!'");
+    // "echo" is a shell internal command on Windows and doesn't work.
+    $command = DIRECTORY_SEPARATOR === "\\" ? "cmd /c echo Hello World!" : "echo 'Hello, world!'";
+
+    $process = new Process($command);
+    $process->start();
 
     echo yield new Message($process->getStdout());
 
diff --git a/examples/ping-many.php b/examples/ping-many.php
index b618d4e..1b61775 100644
--- a/examples/ping-many.php
+++ b/examples/ping-many.php
@@ -6,19 +6,18 @@ use Amp\Process\Process;
 use Amp\Promise;
 use function Amp\Promise\all;
 
-function show_process_output(Promise $promise): \Generator
+function show_process_output(Process $process): \Generator
 {
-    /** @var Process $process */
-    $process = yield $promise;
-
     $stream = $process->getStdout();
-    while ($chunk = yield $stream->read()) {
+
+    while (null !== $chunk = yield $stream->read()) {
         echo $chunk;
     }
 
     $code = yield $process->join();
+    $pid = yield $process->getPid();
 
-    echo "Process {$process->getPid()} exited with {$code}\n";
+    echo "Process {$pid} exited with {$code}\n";
 }
 
 Amp\Loop::run(function () {
@@ -27,7 +26,9 @@ Amp\Loop::run(function () {
     $promises = [];
 
     foreach ($hosts as $host) {
-        $promises[] = new \Amp\Coroutine(show_process_output(Process::start("ping {$host}")));
+        $process = new Process("ping {$host}");
+        $process->start();
+        $promises[] = new \Amp\Coroutine(show_process_output($process));
     }
 
     yield all($promises);
diff --git a/examples/watch-live.php b/examples/watch-live.php
index 0d1b7b9..1214eab 100644
--- a/examples/watch-live.php
+++ b/examples/watch-live.php
@@ -5,10 +5,12 @@ include dirname(__DIR__) . "/vendor/autoload.php";
 use Amp\Process\Process;
 
 Amp\Loop::run(function () {
-    $process = yield Process::start("echo 1; sleep 1; echo 2; sleep 1; echo 3; exit 42");
+    $process = new Process("echo 1; sleep 1; echo 2; sleep 1; echo 3; exit 42");
+    $process->start();
 
     $stream = $process->getStdout();
-    while ($chunk = yield $stream->read()) {
+
+    while (null !== $chunk = yield $stream->read()) {
         echo $chunk;
     }
 
diff --git a/examples/write-command.php b/examples/write-command.php
index 373830b..96601b7 100644
--- a/examples/write-command.php
+++ b/examples/write-command.php
@@ -6,7 +6,13 @@ use Amp\ByteStream\Message;
 use Amp\Process\Process;
 
 Amp\Loop::run(function () {
-    $process = yield Process::start('read ; echo "$REPLY"');
+    if (DIRECTORY_SEPARATOR === "\\") {
+        echo "This example doesn't work on Windows." . PHP_EOL;
+        exit(1);
+    }
+
+    $process = new Process('read; echo "$REPLY"');
+    $process->start();
 
     /* send to stdin */
     $process->getStdin()->write("abc\n");
diff --git a/lib/Internal/Posix/Handle.php b/lib/Internal/Posix/Handle.php
index 1747c85..c1da8a4 100644
--- a/lib/Internal/Posix/Handle.php
+++ b/lib/Internal/Posix/Handle.php
@@ -24,6 +24,9 @@ final class Handle extends ProcessHandle {
     /** @var string */
     public $extraDataPipeWatcher;
 
+    /** @var string */
+    public $extraDataPipeStartWatcher;
+
     /** @var int */
     public $originalParentPid;
 }
diff --git a/lib/Internal/Posix/Runner.php b/lib/Internal/Posix/Runner.php
index ba6a61b..e2585e5 100644
--- a/lib/Internal/Posix/Runner.php
+++ b/lib/Internal/Posix/Runner.php
@@ -24,6 +24,7 @@ final class Runner implements ProcessRunner {
 
     public static function onProcessEndExtraDataPipeReadable($watcher, $stream, Handle $handle) {
         Loop::cancel($watcher);
+        $handle->extraDataPipeWatcher = null;
 
         $handle->status = ProcessStatus::ENDED;
 
@@ -55,14 +56,13 @@ final class Runner implements ProcessRunner {
 
         $handle->status = ProcessStatus::RUNNING;
         $handle->pidDeferred->resolve((int) $pid);
-        $deferreds[0]->resolve(new ResourceOutputStream($pipes[0]));
-        $deferreds[1]->resolve(new ResourceInputStream($pipes[1]));
-        $deferreds[2]->resolve(new ResourceInputStream($pipes[2]));
+        $deferreds[0]->resolve($pipes[0]);
+        $deferreds[1]->resolve($pipes[1]);
+        $deferreds[2]->resolve($pipes[2]);
 
-        $handle->extraDataPipeWatcher = Loop::onReadable($stream, [self::class, 'onProcessEndExtraDataPipeReadable'], $handle);
-        Loop::unreference($handle->extraDataPipeWatcher);
-
-        $handle->sockets->resolve();
+        if ($handle->extraDataPipeWatcher !== null) {
+            Loop::enable($handle->extraDataPipeWatcher);
+        }
     }
 
     /** @inheritdoc */
@@ -104,10 +104,18 @@ final class Runner implements ProcessRunner {
 
         \stream_set_blocking($pipes[3], false);
 
-        Loop::onReadable($pipes[3], [self::class, 'onProcessStartExtraDataPipeReadable'], [$handle, $pipes, [
+        $handle->extraDataPipeStartWatcher = Loop::onReadable($pipes[3], [self::class, 'onProcessStartExtraDataPipeReadable'], [$handle, [
+            new ResourceOutputStream($pipes[0]),
+            new ResourceInputStream($pipes[1]),
+            new ResourceInputStream($pipes[2]),
+        ], [
             $stdinDeferred, $stdoutDeferred, $stderrDeferred
         ]]);
 
+        $handle->extraDataPipeWatcher = Loop::onReadable($pipes[3], [self::class, 'onProcessEndExtraDataPipeReadable'], $handle);
+        Loop::unreference($handle->extraDataPipeWatcher);
+        Loop::disable($handle->extraDataPipeWatcher);
+
         return $handle;
     }
 
@@ -124,13 +132,21 @@ final class Runner implements ProcessRunner {
     /** @inheritdoc */
     public function kill(ProcessHandle $handle) {
         /** @var Handle $handle */
+        if ($handle->extraDataPipeWatcher !== null) {
+            Loop::cancel($handle->extraDataPipeWatcher);
+            $handle->extraDataPipeWatcher = null;
+        }
+
+        /** @var Handle $handle */
+        if ($handle->extraDataPipeStartWatcher !== null) {
+            Loop::cancel($handle->extraDataPipeStartWatcher);
+            $handle->extraDataPipeStartWatcher = null;
+        }
+
         if (!\proc_terminate($handle->proc, 9)) { // Forcefully kill the process using SIGKILL.
             throw new ProcessException("Terminating process failed");
         }
 
-        Loop::cancel($handle->extraDataPipeWatcher);
-        $handle->extraDataPipeWatcher = null;
-
         $handle->status = ProcessStatus::ENDED;
         $handle->joinDeferred->fail(new ProcessException("The process was killed"));
     }
@@ -147,11 +163,23 @@ final class Runner implements ProcessRunner {
     public function destroy(ProcessHandle $handle) {
         /** @var Handle $handle */
         if ($handle->status < ProcessStatus::ENDED && \getmypid() === $handle->originalParentPid) {
-            $this->kill($handle);
+            try {
+                $this->kill($handle);
+            } catch (ProcessException $e) {
+                // ignore
+            }
         }
 
+        /** @var Handle $handle */
         if ($handle->extraDataPipeWatcher !== null) {
             Loop::cancel($handle->extraDataPipeWatcher);
+            $handle->extraDataPipeWatcher = null;
+        }
+
+        /** @var Handle $handle */
+        if ($handle->extraDataPipeStartWatcher !== null) {
+            Loop::cancel($handle->extraDataPipeStartWatcher);
+            $handle->extraDataPipeStartWatcher = null;
         }
 
         if (\is_resource($handle->extraDataPipe)) {
diff --git a/lib/Internal/Windows/Handle.php b/lib/Internal/Windows/Handle.php
index 196180f..58d5507 100644
--- a/lib/Internal/Windows/Handle.php
+++ b/lib/Internal/Windows/Handle.php
@@ -8,6 +8,7 @@ use Amp\Process\Internal\ProcessHandle;
 final class Handle extends ProcessHandle {
     public function __construct() {
         $this->joinDeferred = new Deferred;
+        $this->pidDeferred = new Deferred;
     }
 
     /** @var Deferred */
@@ -16,6 +17,9 @@ final class Handle extends ProcessHandle {
     /** @var string */
     public $exitCodeWatcher;
 
+    /** @var bool */
+    public $exitCodeRequested = false;
+
     /** @var resource */
     public $proc;
 
@@ -26,7 +30,7 @@ final class Handle extends ProcessHandle {
     public $wrapperStderrPipe;
 
     /** @var resource[] */
-    public $sockets;
+    public $sockets = [];
 
     /** @var Deferred[] */
     public $stdioDeferreds;
diff --git a/lib/Internal/Windows/Runner.php b/lib/Internal/Windows/Runner.php
index 03e4681..ed00764 100644
--- a/lib/Internal/Windows/Runner.php
+++ b/lib/Internal/Windows/Runner.php
@@ -27,7 +27,7 @@ final class Runner implements ProcessRunner {
 
     private $socketConnector;
 
-    private function makeCommand(string $command, string $workingDirectory): string {
+    private function makeCommand(string $workingDirectory): string {
         $result = sprintf(
             '%s --address=%s --port=%d --token-size=%d',
             \escapeshellarg(self::WRAPPER_EXE_PATH),
@@ -40,8 +40,6 @@ final class Runner implements ProcessRunner {
             $result .= ' ' . \escapeshellarg('--cwd=' . \rtrim($workingDirectory, '\\'));
         }
 
-        $result .= ' ' . $command;
-
         return $result;
     }
 
@@ -51,12 +49,14 @@ final class Runner implements ProcessRunner {
 
     /** @inheritdoc */
     public function start(string $command, string $cwd = null, array $env = [], array $options = []): ProcessHandle {
-        $command = $this->makeCommand($command, $cwd ?? '');
+        if (strpos($command, "\0") !== false) {
+            throw new ProcessException("Can't execute commands that contain null bytes.");
+        }
 
         $options['bypass_shell'] = true;
 
         $handle = new Handle;
-        $handle->proc = @\proc_open($command, self::FD_SPEC, $pipes, $cwd ?: null, $env ?: null, $options);
+        $handle->proc = @\proc_open($this->makeCommand($cwd ?? ''), self::FD_SPEC, $pipes, $cwd ?: null, $env ?: null, $options);
 
         if (!\is_resource($handle->proc)) {
             $message = "Could not start process";
@@ -74,16 +74,16 @@ final class Runner implements ProcessRunner {
         }
 
         $securityTokens = \random_bytes(SocketConnector::SECURITY_TOKEN_SIZE * 6);
-        $written = \fwrite($pipes[0], $securityTokens);
+        $written = \fwrite($pipes[0], $securityTokens . "\0" . $command . "\0");
 
         \fclose($pipes[0]);
         \fclose($pipes[1]);
 
-        if ($written !== SocketConnector::SECURITY_TOKEN_SIZE * 6) {
+        if ($written !== SocketConnector::SECURITY_TOKEN_SIZE * 6 + \strlen($command) + 2) {
             \fclose($pipes[2]);
             \proc_close($handle->proc);
 
-            throw new ProcessException("Could not send security tokens to process wrapper");
+            throw new ProcessException("Could not send security tokens / command to process wrapper");
         }
 
         $handle->securityTokens = \str_split($securityTokens, SocketConnector::SECURITY_TOKEN_SIZE);
@@ -91,13 +91,16 @@ final class Runner implements ProcessRunner {
         $handle->wrapperStderrPipe = $pipes[2];
 
         $stdinDeferred = new Deferred;
-        $handle->stdioDeferreds[] = new ProcessOutputStream($stdinDeferred->promise());
+        $handle->stdioDeferreds[] = $stdinDeferred;
+        $handle->stdin = new ProcessOutputStream($stdinDeferred->promise());
 
         $stdoutDeferred = new Deferred;
-        $handle->stdioDeferreds[] = new ProcessInputStream($stdoutDeferred->promise());
+        $handle->stdioDeferreds[] = $stdoutDeferred;
+        $handle->stdout = new ProcessInputStream($stdoutDeferred->promise());
 
         $stderrDeferred = new Deferred;
-        $handle->stdioDeferreds[] = new ProcessInputStream($stderrDeferred->promise());
+        $handle->stdioDeferreds[] = $stderrDeferred;
+        $handle->stderr = new ProcessInputStream($stderrDeferred->promise());
 
         $this->socketConnector->registerPendingProcess($handle);
 
@@ -107,6 +110,8 @@ final class Runner implements ProcessRunner {
     /** @inheritdoc */
     public function join(ProcessHandle $handle): Promise {
         /** @var Handle $handle */
+        $handle->exitCodeRequested = true;
+
         if ($handle->exitCodeWatcher !== null) {
             Loop::reference($handle->exitCodeWatcher);
         }
@@ -122,8 +127,10 @@ final class Runner implements ProcessRunner {
             throw new ProcessException("Terminating process failed");
         }
 
-        Loop::cancel($handle->exitCodeWatcher);
-        $handle->exitCodeWatcher = null;
+        if ($handle->exitCodeWatcher !== null) {
+            Loop::cancel($handle->exitCodeWatcher);
+            $handle->exitCodeWatcher = null;
+        }
 
         $handle->status = ProcessStatus::ENDED;
         $handle->joinDeferred->fail(new ProcessException("The process was killed"));
@@ -137,12 +144,17 @@ final class Runner implements ProcessRunner {
     /** @inheritdoc */
     public function destroy(ProcessHandle $handle) {
         /** @var Handle $handle */
-        if ($handle->status < ProcessStatus::ENDED) {
-            $this->kill($handle);
+        if ($handle->status < ProcessStatus::ENDED && \is_resource($handle->proc)) {
+            try {
+                $this->kill($handle);
+            } catch (ProcessException $e) {
+                // ignore
+            }
         }
 
         if ($handle->exitCodeWatcher !== null) {
             Loop::cancel($handle->exitCodeWatcher);
+            $handle->exitCodeWatcher = null;
         }
 
         for ($i = 0; $i < 4; $i++) {
@@ -151,8 +163,8 @@ final class Runner implements ProcessRunner {
             }
         }
 
-        \stream_get_contents($handle->wrapperStderrPipe);
-        \fclose($handle->wrapperStderrPipe);
+        @\stream_get_contents($handle->wrapperStderrPipe);
+        @\fclose($handle->wrapperStderrPipe);
 
         if (\is_resource($handle->proc)) {
             \proc_close($handle->proc);
diff --git a/lib/Internal/Windows/SocketConnector.php b/lib/Internal/Windows/SocketConnector.php
index 853e3bc..5f516eb 100644
--- a/lib/Internal/Windows/SocketConnector.php
+++ b/lib/Internal/Windows/SocketConnector.php
@@ -46,7 +46,7 @@ final class SocketConnector {
         Loop::unreference(Loop::onReadable($this->server, [$this, 'onServerSocketReadable']));
     }
 
-    private function failClientHandshake($socket, int $code): void {
+    private function failClientHandshake($socket, int $code) {
         \fwrite($socket, \chr(SignalCode::HANDSHAKE_ACK) . \chr($code));
         \fclose($socket);
 
@@ -84,10 +84,6 @@ final class SocketConnector {
         $data = \fread($socket, $length);
 
         if ($data === false || $data === '') {
-            \fclose($socket);
-            Loop::cancel($state->readWatcher);
-            Loop::cancel($state->timeoutWatcher);
-            unset($this->pendingClients[(int) $socket]);
             return null;
         }
 
@@ -204,16 +200,15 @@ final class SocketConnector {
     }
 
     public function onReadableChildPid($watcher, $socket, Handle $handle) {
-        Loop::cancel($watcher);
-        Loop::cancel($handle->connectTimeoutWatcher);
-
         $data = \fread($socket, 5);
 
         if ($data === false || $data === '') {
-            $this->failHandleStart($handle, 'Failed to read PID from wrapper: No data received');
             return;
         }
 
+        Loop::cancel($watcher);
+        Loop::cancel($handle->connectTimeoutWatcher);
+
         if (\strlen($data) !== 5) {
             $this->failHandleStart(
                 $handle, 'Failed to read PID from wrapper: Received %d of 5 expected bytes', \strlen($data)
@@ -237,27 +232,27 @@ final class SocketConnector {
         $handle->stdioDeferreds[2]->resolve(new ResourceInputStream($handle->sockets[2]));
 
         $handle->exitCodeWatcher = Loop::onReadable($handle->sockets[0], [$this, 'onReadableExitCode'], $handle);
-        Loop::unreference($handle->exitCodeWatcher);
+        if (!$handle->exitCodeRequested) {
+            Loop::unreference($handle->exitCodeWatcher);
+        }
 
         unset($this->pendingProcesses[$handle->wrapperPid]);
     }
 
     public function onReadableExitCode($watcher, $socket, Handle $handle) {
-        $handle->exitCodeWatcher = null;
-        Loop::cancel($watcher);
-
         $data = \fread($socket, 5);
 
         if ($data === false || $data === '') {
-            $handle->status = ProcessStatus::ENDED;
-            $handle->joinDeferred->fail(new ProcessException('Failed to read exit code from wrapper: No data received'));
             return;
         }
 
+        $handle->exitCodeWatcher = null;
+        Loop::cancel($watcher);
+
         if (\strlen($data) !== 5) {
             $handle->status = ProcessStatus::ENDED;
             $handle->joinDeferred->fail(new ProcessException(
-                \sprintf('Failed to read exit code from wrapper: Recieved %d of 5 expected bytes', \strlen($data))
+                \sprintf('Failed to read exit code from wrapper: Received %d of 5 expected bytes', \strlen($data))
             ));
             return;
         }
@@ -317,6 +312,8 @@ final class SocketConnector {
         foreach ($handle->stdioDeferreds as $deferred) {
             $deferred->fail($error);
         }
+
+        $handle->joinDeferred->fail($error);
     }
 
     public function registerPendingProcess(Handle $handle) {
diff --git a/lib/Process.php b/lib/Process.php
index fcfe91c..9e7cf4d 100644
--- a/lib/Process.php
+++ b/lib/Process.php
@@ -2,6 +2,7 @@
 
 namespace Amp\Process;
 
+use Amp\Loop;
 use Amp\Process\Internal\Posix\Runner as PosixProcessRunner;
 use Amp\Process\Internal\ProcessHandle;
 use Amp\Process\Internal\ProcessRunner;
@@ -11,7 +12,7 @@ use Amp\Promise;
 
 class Process {
     /** @var ProcessRunner */
-    private static $processRunner;
+    private $processRunner;
 
     /** @var string */
     private $command;
@@ -57,6 +58,16 @@ class Process {
         $this->cwd = $cwd;
         $this->env = $envVars;
         $this->options = $options;
+
+        $this->processRunner = Loop::getState(self::class);
+
+        if ($this->processRunner === null) {
+            $this->processRunner = \strncasecmp(\PHP_OS, "WIN", 3) === 0
+                ? new WindowsProcessRunner
+                : new PosixProcessRunner;
+
+            Loop::setState(self::class, $this->processRunner);
+        }
     }
 
     /**
@@ -64,7 +75,7 @@ class Process {
      */
     public function __destruct() {
         if ($this->handle !== null) {
-            self::$processRunner->destroy($this->handle);
+            $this->processRunner->destroy($this->handle);
         }
     }
 
@@ -82,7 +93,7 @@ class Process {
             throw new StatusError("Process has already been started.");
         }
 
-        $this->handle = self::$processRunner->start($this->command, $this->cwd, $this->env, $this->options);
+        $this->handle = $this->processRunner->start($this->command, $this->cwd, $this->env, $this->options);
     }
 
     /**
@@ -97,7 +108,7 @@ class Process {
             throw new StatusError("Process has not been started.");
         }
 
-        return self::$processRunner->join($this->handle);
+        return $this->processRunner->join($this->handle);
     }
 
     /**
@@ -111,7 +122,7 @@ class Process {
             throw new StatusError("The process is not running");
         }
 
-        self::$processRunner->kill($this->handle);
+        $this->processRunner->kill($this->handle);
     }
 
     /**
@@ -127,7 +138,7 @@ class Process {
             throw new StatusError("The process is not running");
         }
 
-        self::$processRunner->signal($this->handle, $signo);
+        $this->processRunner->signal($this->handle, $signo);
     }
 
     /**
@@ -200,7 +211,7 @@ class Process {
      * @return ProcessOutputStream
      */
     public function getStdin(): ProcessOutputStream {
-        return $this->stdin;
+        return $this->handle->stdin;
     }
 
     /**
@@ -213,7 +224,7 @@ class Process {
             throw new StatusError("The process is not running");
         }
 
-        return $this->stdout;
+        return $this->handle->stdout;
     }
 
     /**
@@ -226,13 +237,6 @@ class Process {
             throw new StatusError("The process is not running");
         }
 
-        return $this->stderr;
+        return $this->handle->stderr;
     }
 }
-
-(function () {
-    /** @noinspection PhpUndefinedClassInspection */
-    self::$processRunner = \strncasecmp(\PHP_OS, "WIN", 3) === 0
-        ? new WindowsProcessRunner
-        : new PosixProcessRunner;
-})->bindTo(null, Process::class)();
diff --git a/lib/ProcessInputStream.php b/lib/ProcessInputStream.php
index ec43048..92992b1 100644
--- a/lib/ProcessInputStream.php
+++ b/lib/ProcessInputStream.php
@@ -17,6 +17,9 @@ class ProcessInputStream implements InputStream {
     /** @var bool */
     private $shouldClose = false;
 
+    /** @var bool */
+    private $referenced = true;
+
     /** @var ResourceInputStream */
     private $resourceStream;
 
@@ -27,12 +30,18 @@ class ProcessInputStream implements InputStream {
         $resourceStreamPromise->onResolve(function ($error, $resourceStream) {
             if ($error) {
                 $this->error = new StreamException("Failed to launch process", 0, $error);
-                $this->initialRead->fail($this->error);
+                if ($this->initialRead) {
+                    $this->initialRead->fail($this->error);
+                }
                 return;
             }
 
             $this->resourceStream = $resourceStream;
 
+            if (!$this->referenced) {
+                $this->resourceStream->unreference();
+            }
+
             if ($this->shouldClose) {
                 $this->resourceStream->close();
             }
@@ -70,6 +79,22 @@ class ProcessInputStream implements InputStream {
         return $this->initialRead->promise();
     }
 
+    public function reference() {
+        $this->referenced = true;
+
+        if ($this->resourceStream) {
+            $this->resourceStream->reference();
+        }
+    }
+
+    public function unreference() {
+        $this->referenced = false;
+
+        if ($this->resourceStream) {
+            $this->resourceStream->unreference();
+        }
+    }
+
     public function close() {
         $this->shouldClose = true;
 
diff --git a/lib/ProcessOutputStream.php b/lib/ProcessOutputStream.php
index de84be1..29d8f11 100644
--- a/lib/ProcessOutputStream.php
+++ b/lib/ProcessOutputStream.php
@@ -12,7 +12,7 @@ use Amp\Promise;
 
 class ProcessOutputStream implements OutputStream {
     /** @var array */
-    private $queuedWrites;
+    private $queuedWrites = [];
 
     /** @var bool */
     private $shouldClose = false;
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 4856517..e535180 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,17 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit
-        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/4.1/phpunit.xsd"
-        backupGlobals="false"
-        backupStaticAttributes="false"
-        bootstrap="vendor/autoload.php"
-        colors="true"
-        convertErrorsToExceptions="true"
-        convertNoticesToExceptions="true"
-        convertWarningsToExceptions="true"
-        processIsolation="false"
-        stopOnFailure="false"
->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/6.0/phpunit.xsd" bootstrap="vendor/autoload.php" colors="true">
     <testsuites>
         <testsuite name="Amp Process">
             <directory>test</directory>
diff --git a/test/ProcessTest.php b/test/ProcessTest.php
index ac914fc..2e1ff71 100644
--- a/test/ProcessTest.php
+++ b/test/ProcessTest.php
@@ -7,7 +7,7 @@ use Amp\Process\Process;
 use PHPUnit\Framework\TestCase;
 
 class ProcessTest extends TestCase {
-    const CMD_PROCESS = 'echo foo';
+    const CMD_PROCESS = \DIRECTORY_SEPARATOR === "\\" ? "cmd /c echo foo" : "echo foo";
 
     /**
      * @expectedException \Amp\Process\StatusError
@@ -22,7 +22,7 @@ class ProcessTest extends TestCase {
 
     public function testIsRunning() {
         Loop::run(function () {
-            $process = new Process("exit 42");
+            $process = new Process(\DIRECTORY_SEPARATOR === "\\" ? "cmd /c exit 42" : "exit 42");
             $process->start();
             $promise = $process->join();
 
@@ -36,8 +36,9 @@ class ProcessTest extends TestCase {
 
     public function testExecuteResolvesToExitCode() {
         Loop::run(function () {
-            $process = new Process("exit 42");
+            $process = new Process(\DIRECTORY_SEPARATOR === "\\" ? "cmd /c exit 42" : "exit 42");
             $process->start();
+
             $code = yield $process->join();
 
             $this->assertSame(42, $code);
@@ -54,7 +55,7 @@ class ProcessTest extends TestCase {
             $completed = false;
             $promise->onResolve(function () use (&$completed) { $completed = true; });
             $this->assertFalse($completed);
-            $this->assertInternalType('int', $process->getPid());
+            $this->assertInternalType('int', yield $process->getPid());
         });
     }
 
@@ -70,7 +71,7 @@ class ProcessTest extends TestCase {
 
             $process->kill();
 
-            $code = yield $promise;
+            yield $promise;
         });
     }