Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/phpspec/prophecy/spec/Prophecy/Promise/ThrowPromiseSpec.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace spec\Prophecy\Promise;
+
+use PhpSpec\ObjectBehavior;
+
+class ThrowPromiseSpec extends ObjectBehavior
+{
+    function let()
+    {
+        $this->beConstructedWith('RuntimeException');
+    }
+
+    function it_is_promise()
+    {
+        $this->shouldBeAnInstanceOf('Prophecy\Promise\PromiseInterface');
+    }
+
+    /**
+     * @param \Prophecy\Prophecy\ObjectProphecy $object
+     * @param \Prophecy\Prophecy\MethodProphecy $method
+     */
+    function it_instantiates_and_throws_exception_from_provided_classname($object, $method)
+    {
+        $this->beConstructedWith('InvalidArgumentException');
+
+        $this->shouldThrow('InvalidArgumentException')
+            ->duringExecute(array(), $object, $method);
+    }
+
+    /**
+     * @param \Prophecy\Prophecy\ObjectProphecy $object
+     * @param \Prophecy\Prophecy\MethodProphecy $method
+     */
+    function it_instantiates_exceptions_with_required_arguments($object, $method)
+    {
+        $this->beConstructedWith('spec\Prophecy\Promise\RequiredArgumentException');
+
+        $this->shouldThrow('spec\Prophecy\Promise\RequiredArgumentException')
+            ->duringExecute(array(), $object, $method);
+    }
+
+    /**
+     * @param \Prophecy\Prophecy\ObjectProphecy $object
+     * @param \Prophecy\Prophecy\MethodProphecy $method
+     */
+    function it_throws_provided_exception($object, $method)
+    {
+        $this->beConstructedWith($exc = new \RuntimeException('Some exception'));
+
+        $this->shouldThrow($exc)->duringExecute(array(), $object, $method);
+    }
+}
+
+class RequiredArgumentException extends \Exception
+{
+    final public function __construct($message, $code) {}
+}