diff --git a/src/Error/FormattedError.php b/src/Error/FormattedError.php
index 3fa4168..6664c20 100644
--- a/src/Error/FormattedError.php
+++ b/src/Error/FormattedError.php
@@ -8,53 +8,49 @@ use GraphQL\Utils\Utils;
 
 /**
  * Class FormattedError
- * @todo move this class to Utils/ErrorUtils
+ * 
  * @package GraphQL\Error
  */
 class FormattedError
 {
     /**
-     * @deprecated as of 8.0
-     * @param $error
-     * @param SourceLocation[] $locations
+     * @param \Throwable $e
+     * @param $debug
+     *
      * @return array
      */
-    public static function create($error, array $locations = [])
+    public static function createFromException($e, $debug = false)
     {
-        $formatted = [
-            'message' => $error
-        ];
-
-        if (!empty($locations)) {
-            $formatted['locations'] = array_map(function($loc) { return $loc->toArray();}, $locations);
+        if ($e instanceof Error) {
+            $result = $e->toSerializableArray();
+        } else if ($e instanceof \ErrorException) {
+            $result = [
+                'message' => $e->getMessage(),
+            ];
+            if ($debug) {
+                $result += [
+                    'file' => $e->getFile(),
+                    'line' => $e->getLine(),
+                    'severity' => $e->getSeverity()
+                ];
+            }
+        } else {
+            Utils::invariant(
+                $e instanceof \Exception || $e instanceof \Throwable,
+                "Expected exception, got %s",
+                Utils::getVariableType($e)
+            );
+            $result = [
+                'message' => $e->getMessage()
+            ];
         }
 
-        return $formatted;
-    }
+        if ($debug) {
+            $debugging = $e->getPrevious() ?: $e;
+            $result['trace'] = static::toSafeTrace($debugging->getTrace());
+        }
 
-    /**
-     * @param \ErrorException $e
-     * @return array
-     */
-    public static function createFromPHPError(\ErrorException $e)
-    {
-        return [
-            'message' => $e->getMessage(),
-            'severity' => $e->getSeverity(),
-            'trace' => self::toSafeTrace($e->getTrace())
-        ];
-    }
-
-    /**
-     * @param \Throwable $e
-     * @return array
-     */
-    public static function createFromException($e)
-    {
-        return [
-            'message' => $e->getMessage(),
-            'trace' => self::toSafeTrace($e->getTrace())
-        ];
+        return $result;
     }
 
     /**
@@ -133,4 +129,37 @@ class FormattedError
         }
         return gettype($var);
     }
+
+    /**
+     * @deprecated as of v0.8.0
+     * @param $error
+     * @param SourceLocation[] $locations
+     * @return array
+     */
+    public static function create($error, array $locations = [])
+    {
+        $formatted = [
+            'message' => $error
+        ];
+
+        if (!empty($locations)) {
+            $formatted['locations'] = array_map(function($loc) { return $loc->toArray();}, $locations);
+        }
+
+        return $formatted;
+    }
+
+    /**
+     * @param \ErrorException $e
+     * @deprecated as of v0.10.0, use general purpose method createFromException() instead
+     * @return array
+     */
+    public static function createFromPHPError(\ErrorException $e)
+    {
+        return [
+            'message' => $e->getMessage(),
+            'severity' => $e->getSeverity(),
+            'trace' => self::toSafeTrace($e->getTrace())
+        ];
+    }
 }
diff --git a/src/Server.php b/src/Server.php
index 22edbfe..3350b1f 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -15,6 +15,11 @@ use GraphQL\Type\Resolution;
 use GraphQL\Validator\DocumentValidator;
 use GraphQL\Utils\Utils;
 
+trigger_error(
+    'GraphQL\Server is deprecated in favor of new implementation: GraphQL\Server\StandardServer and will be removed in next version',
+    E_USER_DEPRECATED
+);
+
 class Server
 {
     const DEBUG_PHP_ERRORS = 1;
diff --git a/src/Server/Helper.php b/src/Server/Helper.php
new file mode 100644
index 0000000..f863908
--- /dev/null
+++ b/src/Server/Helper.php
@@ -0,0 +1,191 @@
+<?php
+namespace GraphQL\Server;
+
+use GraphQL\Error\FormattedError;
+use GraphQL\Error\InvariantViolation;
+use GraphQL\Error\UserError;
+use GraphQL\Executor\ExecutionResult;
+use GraphQL\Executor\Promise\Promise;
+use GraphQL\GraphQL;
+use GraphQL\Language\AST\DocumentNode;
+use GraphQL\Language\Parser;
+use GraphQL\Utils\AST;
+use GraphQL\Utils\Utils;
+
+/**
+ * Class Helper
+ * Contains functionality that could be re-used by various server implementations
+ *
+ * @package GraphQL\Server
+ */
+class Helper
+{
+    /**
+     * Executes GraphQL operation with given server configuration and returns execution result (or promise)
+     *
+     * @param ServerConfig $config
+     * @param OperationParams $op
+     *
+     * @return ExecutionResult|Promise
+     */
+    public static function executeOperation(ServerConfig $config, OperationParams $op)
+    {
+        $phpErrors = [];
+        $execute = function() use ($config, $op) {
+            $doc = $op->queryId ? static::loadPersistedQuery($config, $op) : $op->query;
+
+            if (!$doc instanceof DocumentNode) {
+                $doc = Parser::parse($doc);
+            }
+            if (!$op->allowsMutation() && AST::isMutation($op->operation, $doc)) {
+                throw new UserError("Cannot execute mutation in read-only context");
+            }
+
+            return GraphQL::executeAndReturnResult(
+                $config->getSchema(),
+                $doc,
+                $config->getRootValue(),
+                $config->getContext(),
+                $op->variables,
+                $op->operation,
+                $config->getDefaultFieldResolver(),
+                static::resolveValidationRules($config, $op),
+                $config->getPromiseAdapter()
+            );
+        };
+        if ($config->getDebug()) {
+            $execute = Utils::withErrorHandling($execute, $phpErrors);
+        }
+        $result = $execute();
+
+        $applyErrorFormatting = function(ExecutionResult $result) use ($config, $phpErrors) {
+            if ($config->getDebug()) {
+                $errorFormatter = function($e) {
+                    return FormattedError::createFromException($e, true);
+                };
+            } else {
+                $errorFormatter = $config->getErrorFormatter();
+            }
+            if (!empty($phpErrors)) {
+                $result->extensions['phpErrors'] = array_map($errorFormatter, $phpErrors);
+            }
+            $result->setErrorFormatter($errorFormatter);
+            return $result;
+        };
+
+        return $result instanceof Promise ?
+            $result->then($applyErrorFormatting) :
+            $applyErrorFormatting($result);
+    }
+
+    /**
+     * @param ServerConfig $config
+     * @param OperationParams $op
+     * @return string|DocumentNode
+     */
+    private static function loadPersistedQuery(ServerConfig $config, OperationParams $op)
+    {
+        // Load query if we got persisted query id:
+        $loader = $config->getPersistentQueryLoader();
+
+        if (!$loader) {
+            throw new UserError("Persisted queries are not supported by this server");
+        }
+
+        $source = $loader($op->queryId, $op);
+
+        if (!is_string($source) && !$source instanceof DocumentNode) {
+            throw new InvariantViolation(sprintf(
+                "Persistent query loader must return query string or instance of %s but got: %s",
+                DocumentNode::class,
+                Utils::printSafe($source)
+            ));
+        }
+
+        return $source;
+    }
+
+    /**
+     * @param ServerConfig $config
+     * @param OperationParams $params
+     * @return array
+     */
+    private static function resolveValidationRules(ServerConfig $config, OperationParams $params)
+    {
+        // Allow customizing validation rules per operation:
+        $validationRules = $config->getValidationRules();
+
+        if (is_callable($validationRules)) {
+            $validationRules = $validationRules($params);
+
+            if (!is_array($validationRules)) {
+                throw new InvariantViolation(
+                    "Validation rules callable must return array of rules, but got: %s" .
+                    Utils::printSafe($validationRules)
+                );
+            }
+        }
+
+        return $validationRules;
+    }
+
+    /**
+     * Parses HTTP request and returns GraphQL QueryParams contained in this request.
+     * For batched requests it returns an array of QueryParams.
+     *
+     * @return OperationParams|OperationParams[]
+     */
+    public static function parseHttpRequest()
+    {
+        $contentType = isset($_SERVER['CONTENT_TYPE']) ? $_SERVER['CONTENT_TYPE'] : null;
+
+        $assertValid = function (OperationParams $opParams, $queryNum = null) {
+            $errors = $opParams->validate();
+            if (!empty($errors[0])) {
+                $err = $queryNum ? "Error in query #$queryNum: {$errors[0]}" : $errors[0];
+                throw new UserError($err);
+            }
+        };
+
+        if (stripos($contentType, 'application/graphql' !== false)) {
+            $body = file_get_contents('php://input') ?: '';
+            $op = OperationParams::create(['query' => $body]);
+            $assertValid($op);
+        } else if (stripos($contentType, 'application/json') !== false || stripos($contentType, 'text/json') !== false) {
+            $body = file_get_contents('php://input') ?: '';
+            $data = json_decode($body, true);
+
+            if (json_last_error()) {
+                throw new UserError("Could not parse JSON: " . json_last_error_msg());
+            }
+            if (!is_array($data)) {
+                throw new UserError(
+                    "GraphQL Server expects JSON object or array, but got %s" .
+                    Utils::printSafe($data)
+                );
+            }
+            if (isset($data[0])) {
+                $op = [];
+                foreach ($data as $index => $entry) {
+                    $params = OperationParams::create($entry);
+                    $assertValid($params, $index);
+                    $op[] = $params;
+                }
+            } else {
+                $op = OperationParams::create($data);
+                $assertValid($op);
+            }
+        } else if (stripos($contentType, 'application/x-www-form-urlencoded') !== false) {
+            if ($_SERVER['REQUEST_METHOD'] === 'GET') {
+                $op = OperationParams::create($_GET, false);
+            } else {
+                $op = OperationParams::create($_POST);
+            }
+            $assertValid($op);
+        } else {
+            throw new UserError("Bad request: unexpected content type: " . Utils::printSafe($contentType));
+        }
+
+        return $op;
+    }
+}
diff --git a/src/Server/OperationParams.php b/src/Server/OperationParams.php
new file mode 100644
index 0000000..2a187ca
--- /dev/null
+++ b/src/Server/OperationParams.php
@@ -0,0 +1,120 @@
+<?php
+namespace GraphQL\Server;
+use GraphQL\Utils;
+
+/**
+ * Class QueryParams
+ * Represents all available parsed query parameters
+ *
+ * @package GraphQL\Server
+ */
+class OperationParams
+{
+    /**
+     * @var string
+     */
+    public $query;
+
+    /**
+     * @var string
+     */
+    public $queryId;
+
+    /**
+     * @var string
+     */
+    public $operation;
+
+    /**
+     * @var array
+     */
+    public $variables;
+
+    /**
+     * @var array
+     */
+    private $originalInput;
+
+    /**
+     * @var bool
+     */
+    private $allowsMutations;
+
+    /**
+     * Creates an instance from given array
+     *
+     * @param array $params
+     * @param bool $allowsMutations
+     *
+     * @return static
+     */
+    public static function create(array $params, $allowsMutations = true)
+    {
+        $instance = new static();
+        $instance->originalInput = $params;
+
+        $params = array_change_key_case($params, CASE_LOWER);
+
+        $params += [
+            'query' => null,
+            'queryid' => null,
+            'documentid' => null, // alias to queryid
+            'operation' => null,
+            'variables' => null
+        ];
+
+        $instance->query = $params['query'];
+        $instance->queryId = $params['queryid'] ?: $params['documentid'];
+        $instance->operation = $params['operation'];
+        $instance->variables = $params['variables'];
+        $instance->allowsMutations = (bool) $allowsMutations;
+
+        return $instance;
+    }
+
+    /**
+     * @return array
+     */
+    public function validate()
+    {
+        $errors = [];
+        if (!$this->query && !$this->queryId) {
+            $errors[] = 'GraphQL Request must include at least one of those two parameters: "query" or "queryId"';
+        }
+        if ($this->query && $this->queryId) {
+            $errors[] = 'GraphQL Request parameters: "query" and "queryId" are mutually exclusive';
+        }
+
+        if ($this->query !== null && (!is_string($this->query) || empty($this->query))) {
+            $errors[] = 'GraphQL Request parameter "query" must be string, but got: ' .
+                Utils::printSafe($this->query);
+        }
+        if ($this->queryId !== null && (!is_string($this->query) || empty($this->query))) {
+            $errors[] = 'GraphQL Request parameter "queryId" must be string, but got: ' .
+                Utils::printSafe($this->query);
+        }
+
+        if ($this->operation !== null && (!is_string($this->operation) || empty($this->operation))) {
+            $errors[] = 'GraphQL Request parameter "operation" must be string, but got: ' .
+                Utils::printSafe($this->operation);
+        }
+        if ($this->variables !== null && (!is_array($this->variables) || isset($this->variables[0]))) {
+            $errors[] = 'GraphQL Request parameter "variables" must be associative array, but got: ' .
+                Utils::printSafe($this->variables);
+        }
+        return $errors;
+    }
+
+    public function getOriginalInput()
+    {
+        return $this->originalInput;
+    }
+
+    /**
+     * @return bool
+     */
+    public function allowsMutation()
+    {
+        return $this->allowsMutations;
+    }
+}
diff --git a/src/Server/ServerConfig.php b/src/Server/ServerConfig.php
new file mode 100644
index 0000000..e17546f
--- /dev/null
+++ b/src/Server/ServerConfig.php
@@ -0,0 +1,257 @@
+<?php
+namespace GraphQL\Server;
+
+use GraphQL\Error\FormattedError;
+use GraphQL\Error\InvariantViolation;
+use GraphQL\Executor\Promise\PromiseAdapter;
+use GraphQL\Schema;
+use GraphQL\Utils\Utils;
+
+class ServerConfig
+{
+    /**
+     * @return static
+     */
+    public static function create()
+    {
+        return new static();
+    }
+
+    /**
+     * @var Schema
+     */
+    private $schema;
+
+    /**
+     * @var mixed
+     */
+    private $context;
+
+    /**
+     * @var mixed
+     */
+    private $rootValue;
+
+    /**
+     * @var callable
+     */
+    private $errorFormatter = [FormattedError::class, 'createFromException'];
+
+    /**
+     * @var bool
+     */
+    private $debug = false;
+
+    /**
+     * @var array|callable
+     */
+    private $validationRules;
+
+    /**
+     * @var callable
+     */
+    private $defaultFieldResolver;
+
+    /**
+     * @var PromiseAdapter
+     */
+    private $promiseAdapter;
+
+    /**
+     * @var callable
+     */
+    private $persistentQueryLoader;
+
+    /**
+     * @return mixed
+     */
+    public function getContext()
+    {
+        return $this->context;
+    }
+
+    /**
+     * @param mixed $context
+     * @return $this
+     */
+    public function setContext($context)
+    {
+        $this->context = $context;
+        return $this;
+    }
+
+    /**
+     * @param mixed $rootValue
+     * @return $this
+     */
+    public function setRootValue($rootValue)
+    {
+        $this->rootValue = $rootValue;
+        return $this;
+    }
+
+    /**
+     * @return mixed
+     */
+    public function getRootValue()
+    {
+        return $this->rootValue;
+    }
+
+    /**
+     * Set schema instance
+     *
+     * @param Schema $schema
+     * @return $this
+     */
+    public function setSchema(Schema $schema)
+    {
+        $this->schema = $schema;
+        return $this;
+    }
+
+    /**
+     * @return Schema
+     */
+    public function getSchema()
+    {
+        return $this->schema;
+    }
+
+    /**
+     * @return callable
+     */
+    public function getErrorFormatter()
+    {
+        return $this->errorFormatter;
+    }
+
+    /**
+     * Expects function(Throwable $e) : array
+     *
+     * @param callable $errorFormatter
+     * @return $this
+     */
+    public function setErrorFormatter(callable $errorFormatter)
+    {
+        $this->errorFormatter = $errorFormatter;
+        return $this;
+    }
+
+    /**
+     * @return PromiseAdapter
+     */
+    public function getPromiseAdapter()
+    {
+        return $this->promiseAdapter;
+    }
+
+    /**
+     * @param PromiseAdapter $promiseAdapter
+     * @return $this
+     */
+    public function setPromiseAdapter(PromiseAdapter $promiseAdapter)
+    {
+        $this->promiseAdapter = $promiseAdapter;
+        return $this;
+    }
+
+    /**
+     * @return array|callable
+     */
+    public function getValidationRules()
+    {
+        return $this->validationRules;
+    }
+
+    /**
+     * Set validation rules for this server.
+     *
+     * @param array|callable
+     * @return $this
+     */
+    public function setValidationRules($validationRules)
+    {
+        if (!is_callable($validationRules) && !is_array($validationRules) && $validationRules !== null) {
+            throw new InvariantViolation(
+                __METHOD__ . ' expects array of validation rules or callable returning such array, but got: %s' .
+                Utils::printSafe($validationRules)
+            );
+        }
+
+        $this->validationRules = $validationRules;
+        return $this;
+    }
+
+    /**
+     * @return callable
+     */
+    public function getDefaultFieldResolver()
+    {
+        return $this->defaultFieldResolver;
+    }
+
+    /**
+     * @param callable $defaultFieldResolver
+     * @return $this
+     */
+    public function setDefaultFieldResolver(callable $defaultFieldResolver)
+    {
+        $this->defaultFieldResolver = $defaultFieldResolver;
+        return $this;
+    }
+
+    /**
+     * @return callable
+     */
+    public function getPersistentQueryLoader()
+    {
+        return $this->persistentQueryLoader;
+    }
+
+    /**
+     * A function that takes an input id and returns a valid Document.
+     * If provided, this will allow your GraphQL endpoint to execute a document specified via `queryId`.
+     *
+     * @param callable $persistentQueryLoader
+     * @return ServerConfig
+     */
+    public function setPersistentQueryLoader(callable $persistentQueryLoader)
+    {
+        $this->persistentQueryLoader = $persistentQueryLoader;
+        return $this;
+    }
+
+    /**
+     * @return bool
+     */
+    public function getDebug()
+    {
+        return $this->debug;
+    }
+
+    /**
+     * Settings this option has two effects:
+     *
+     * 1. Replaces current error formatter with the one for debugging (has precedence over `setErrorFormatter()`).
+     *    This error formatter adds `trace` entry for all errors in ExecutionResult when it is converted to array.
+     *
+     * 2. All PHP errors are intercepted during query execution (including warnings, notices and deprecations).
+     *
+     *    These PHP errors are converted to arrays with `message`, `file`, `line`, `trace` keys and then added to
+     *    `extensions` section of ExecutionResult under key `phpErrors`.
+     *
+     *    After query execution error handler will be removed from stack,
+     *    so any errors occurring after execution will not be caught.
+     *
+     * Use this feature for development and debugging only.
+     *
+     * @param bool $set
+     * @return $this
+     */
+    public function setDebug($set = true)
+    {
+        $this->debug = (bool) $set;
+        return $this;
+    }
+}
diff --git a/src/Server/StandardServer.php b/src/Server/StandardServer.php
new file mode 100644
index 0000000..d8aebff
--- /dev/null
+++ b/src/Server/StandardServer.php
@@ -0,0 +1,106 @@
+<?php
+namespace GraphQL\Server;
+
+use GraphQL\Error\InvariantViolation;
+use GraphQL\Utils\Utils;
+use GraphQL\Executor\ExecutionResult;
+use GraphQL\Executor\Promise\Promise;
+
+/**
+ * Class StandardServer
+ *
+ * GraphQL server compatible with both:
+ * https://github.com/graphql/express-graphql and https://github.com/apollographql/graphql-server
+ *
+ * @package GraphQL\Server
+ */
+class StandardServer
+{
+    /**
+     * Creates new server
+     *
+     * @param ServerConfig $config
+     * @return static
+     */
+    public static function create(ServerConfig $config)
+    {
+        return new static($config);
+    }
+
+    /**
+     * @var ServerConfig
+     */
+    private $config;
+
+    /**
+     * StandardServer constructor.
+     * @param ServerConfig $config
+     */
+    protected function __construct(ServerConfig $config)
+    {
+        $this->config = $config;
+    }
+
+    /**
+     * @param OperationParams|OperationParams[] $parsedBody
+     * @return ExecutionResult|ExecutionResult[]|Promise
+     */
+    public function executeRequest($parsedBody = null)
+    {
+        if (null !== $parsedBody) {
+            $this->assertBodyIsParsedProperly(__METHOD__, $parsedBody);
+        } else {
+            $parsedBody = Helper::parseHttpRequest();
+        }
+
+        $batched = is_array($parsedBody);
+
+        $result = [];
+        foreach ((array) $parsedBody as $index => $operationParams) {
+            $result[] = Helper::executeOperation($this->config, $operationParams);
+        }
+
+        return $batched ? $result : $result[0];
+    }
+
+    /**
+     * @param $method
+     * @param $parsedBody
+     */
+    private function assertBodyIsParsedProperly($method, $parsedBody)
+    {
+        if (is_array($parsedBody)) {
+            foreach ($parsedBody as $index => $entry) {
+                if (!$entry instanceof OperationParams) {
+                    throw new InvariantViolation(sprintf(
+                        '%s expects instance of %s or array of instances. Got invalid array where entry at position %d is %s',
+                        $method,
+                        OperationParams::class,
+                        $index,
+                        Utils::printSafe($entry)
+                    ));
+                }
+                $errors = $entry->validate();
+
+                if (!empty($errors[0])) {
+                    $err = $index ? "Error in query #$index: {$errors[0]}" : $errors[0];
+                    throw new InvariantViolation($err);
+                }
+            }
+        }
+
+        if ($parsedBody instanceof OperationParams) {
+            $errors = $parsedBody->validate();
+            if (!empty($errors[0])) {
+                throw new InvariantViolation($errors[0]);
+            }
+        }
+
+        throw new InvariantViolation(sprintf(
+            '%s expects instance of %s or array of instances, but got %s',
+            $method,
+            OperationParams::class,
+            Utils::printSafe($parsedBody)
+        ));
+    }
+}
diff --git a/src/Utils/AST.php b/src/Utils/AST.php
index 27cc776..806162a 100644
--- a/src/Utils/AST.php
+++ b/src/Utils/AST.php
@@ -3,6 +3,7 @@ namespace GraphQL\Utils;
 
 use GraphQL\Error\InvariantViolation;
 use GraphQL\Language\AST\BooleanValueNode;
+use GraphQL\Language\AST\DocumentNode;
 use GraphQL\Language\AST\EnumValueNode;
 use GraphQL\Language\AST\FieldNode;
 use GraphQL\Language\AST\FloatValueNode;
@@ -12,6 +13,7 @@ use GraphQL\Language\AST\NameNode;
 use GraphQL\Language\AST\NullValueNode;
 use GraphQL\Language\AST\ObjectFieldNode;
 use GraphQL\Language\AST\ObjectValueNode;
+use GraphQL\Language\AST\OperationDefinitionNode;
 use GraphQL\Language\AST\StringValueNode;
 use GraphQL\Language\AST\ValueNode;
 use GraphQL\Language\AST\VariableNode;
@@ -332,4 +334,23 @@ class AST
         return $valueNode instanceof VariableNode &&
         (!$variables || !array_key_exists($valueNode->name->value, $variables));
     }
+
+    /**
+     * @param string $operation
+     * @param DocumentNode $document
+     * @return bool
+     */
+    public static function isMutation($operation, DocumentNode $document)
+    {
+        if (is_array($document->definitions)) {
+            foreach ($document->definitions as $def) {
+                if ($def instanceof OperationDefinitionNode) {
+                    if ($def->operation === 'mutation' && $def->name->value === $operation) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
 }
diff --git a/src/Utils/Utils.php b/src/Utils/Utils.php
index cb6242b..6de5f05 100644
--- a/src/Utils/Utils.php
+++ b/src/Utils/Utils.php
@@ -385,4 +385,28 @@ class Utils
             );
         }
     }
+
+    /**
+     * Wraps original closure with PHP error handling (using set_error_handler).
+     * Resulting closure will collect all PHP errors that occur during the call in $errors array.
+     *
+     * @param callable $fn
+     * @param \ErrorException[] $errors
+     * @return \Closure
+     */
+    public static function withErrorHandling(callable $fn, array &$errors)
+    {
+        return function() use ($fn, &$errors) {
+            // Catch custom errors (to report them in query results)
+            set_error_handler(function ($severity, $message, $file, $line) use (&$errors) {
+                $errors[] = new \ErrorException($message, 0, $severity, $file, $line);
+            });
+
+            try {
+                return $fn();
+            } finally {
+                restore_error_handler();
+            }
+        };
+    }
 }
diff --git a/tests/Server/QueryExecutionTest.php b/tests/Server/QueryExecutionTest.php
new file mode 100644
index 0000000..092a97c
--- /dev/null
+++ b/tests/Server/QueryExecutionTest.php
@@ -0,0 +1,379 @@
+<?php
+namespace GraphQL\Tests\Server;
+
+use GraphQL\Error\Error;
+use GraphQL\Error\UserError;
+use GraphQL\Executor\ExecutionResult;
+use GraphQL\Language\Parser;
+use GraphQL\Schema;
+use GraphQL\Server\Helper;
+use GraphQL\Server\OperationParams;
+use GraphQL\Server\ServerConfig;
+use GraphQL\Type\Definition\ObjectType;
+use GraphQL\Type\Definition\Type;
+use GraphQL\Validator\DocumentValidator;
+use GraphQL\Validator\ValidationContext;
+
+class QueryExecutionTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var ServerConfig
+     */
+    private $config;
+
+    public function setUp()
+    {
+        $schema = new Schema([
+            'query' => new ObjectType([
+                'name' => 'Query',
+                'fields' => [
+                    'f1' => [
+                        'type' => Type::string(),
+                        'resolve' => function($root, $args, $context, $info) {
+                            return $info->fieldName;
+                        }
+                    ],
+                    'fieldWithPhpError' => [
+                        'type' => Type::string(),
+                        'resolve' => function($root, $args, $context, $info) {
+                            trigger_error('deprecated', E_USER_DEPRECATED);
+                            trigger_error('notice', E_USER_NOTICE);
+                            trigger_error('warning', E_USER_WARNING);
+                            $a = [];
+                            $a['test']; // should produce PHP notice
+                            return $info->fieldName;
+                        }
+                    ],
+                    'fieldWithException' => [
+                        'type' => Type::string(),
+                        'resolve' => function($root, $args, $context, $info) {
+                            throw new \Exception("This is the exception we want");
+                        }
+                    ],
+                    'testContextAndRootValue' => [
+                        'type' => Type::string(),
+                        'resolve' => function($root, $args, $context, $info) {
+                            $context->testedRootValue = $root;
+                            return $info->fieldName;
+                        }
+                    ],
+                    'fieldWithArg' => [
+                        'type' => Type::string(),
+                        'args' => [
+                            'arg' => [
+                                'type' => Type::nonNull(Type::string())
+                            ],
+                        ],
+                        'resolve' => function($root, $args) {
+                            return $args['arg'];
+                        }
+                    ]
+                ]
+            ])
+        ]);
+
+        $this->config = ServerConfig::create()->setSchema($schema);
+    }
+
+    public function testSimpleQueryExecution()
+    {
+        $query = '{f1}';
+
+        $expected = [
+            'data' => [
+                'f1' => 'f1'
+            ]
+        ];
+
+        $this->assertQueryResultEquals($expected, $query);
+    }
+
+    public function testDebugPhpErrors()
+    {
+        $this->config->setDebug(true);
+
+        $query = '
+        {
+            fieldWithPhpError
+            f1
+        }
+        ';
+
+        $expected = [
+            'data' => [
+                'fieldWithPhpError' => 'fieldWithPhpError',
+                'f1' => 'f1'
+            ],
+            'extensions' => [
+                'phpErrors' => [
+                    ['message' => 'deprecated', 'severity' => 16384],
+                    ['message' => 'notice', 'severity' => 1024],
+                    ['message' => 'warning', 'severity' => 512],
+                    ['message' => 'Undefined index: test', 'severity' => 8],
+                ]
+            ]
+        ];
+
+        $result = $this->assertQueryResultEquals($expected, $query);
+
+        // Assert php errors contain trace:
+        $this->assertArrayHasKey('trace', $result->extensions['phpErrors'][0]);
+        $this->assertArrayHasKey('trace', $result->extensions['phpErrors'][1]);
+        $this->assertArrayHasKey('trace', $result->extensions['phpErrors'][2]);
+        $this->assertArrayHasKey('trace', $result->extensions['phpErrors'][3]);
+    }
+
+    public function testDebugExceptions()
+    {
+        $this->config->setDebug(true);
+
+        $query = '
+        {
+            fieldWithException
+            f1
+        }
+        ';
+
+        $expected = [
+            'data' => [
+                'fieldWithException' => null,
+                'f1' => 'f1'
+            ],
+            'errors' => [
+                [
+                    'message' => 'This is the exception we want',
+                    'path' => ['fieldWithException'],
+                    'trace' => []
+                ]
+            ]
+        ];
+
+        $result = $this->executeQuery($query)->toArray();
+        $this->assertArraySubset($expected, $result);
+    }
+
+    public function testPassesRootValueAndContext()
+    {
+        $rootValue = 'myRootValue';
+        $context = new \stdClass();
+
+        $this->config
+            ->setContext($context)
+            ->setRootValue($rootValue);
+
+        $query = '
+        {
+            testContextAndRootValue
+        }
+        ';
+
+        $this->assertTrue(!isset($context->testedRootValue));
+        $this->executeQuery($query);
+        $this->assertSame($rootValue, $context->testedRootValue);
+    }
+
+    public function testPassesVariables()
+    {
+        $variables = ['a' => 'a', 'b' => 'b'];
+        $query = '
+            query ($a: String!, $b: String!) {
+                a: fieldWithArg(arg: $a)
+                b: fieldWithArg(arg: $b)
+            }
+        ';
+        $expected = [
+            'data' => [
+                'a' => 'a',
+                'b' => 'b'
+            ]
+        ];
+        $this->assertQueryResultEquals($expected, $query, $variables);
+    }
+
+    public function testPassesCustomValidationRules()
+    {
+        $query = '
+            {nonExistentField}
+        ';
+        $expected = [
+            'errors' => [
+                ['message' => 'Cannot query field "nonExistentField" on type "Query".']
+            ]
+        ];
+
+        $this->assertQueryResultEquals($expected, $query);
+
+        $called = false;
+
+        $rules = [
+            function() use (&$called) {
+                $called = true;
+                return [];
+            }
+        ];
+
+        $this->config->setValidationRules($rules);
+        $expected = [
+            'data' => []
+        ];
+        $this->assertQueryResultEquals($expected, $query);
+        $this->assertTrue($called);
+    }
+
+    public function testAllowsDifferentValidationRulesDependingOnOperation()
+    {
+        $q1 = '{f1}';
+        $q2 = '{invalid}';
+        $called1 = false;
+        $called2 = false;
+
+        $this->config->setValidationRules(function(OperationParams $params) use ($q1, $q2, &$called1, &$called2) {
+            if ($params->query === $q1) {
+                $called1 = true;
+                return DocumentValidator::allRules();
+            } else {
+                $called2 = true;
+                return [
+                    function(ValidationContext $context) {
+                        $context->reportError(new Error("This is the error we are looking for!"));
+                    }
+                ];
+            }
+        });
+
+        $expected = ['data' => ['f1' => 'f1']];
+        $this->assertQueryResultEquals($expected, $q1);
+        $this->assertTrue($called1);
+        $this->assertFalse($called2);
+
+        $called1 = false;
+        $called2 = false;
+        $expected = ['errors' => [['message' => 'This is the error we are looking for!']]];
+        $this->assertQueryResultEquals($expected, $q2);
+        $this->assertFalse($called1);
+        $this->assertTrue($called2);
+    }
+
+    public function testAllowsSkippingValidation()
+    {
+        $this->config->setValidationRules([]);
+        $query = '{nonExistentField}';
+        $expected = ['data' => []];
+        $this->assertQueryResultEquals($expected, $query);
+    }
+
+    public function testPersistedQueriesAreDisabledByDefault()
+    {
+        $this->setExpectedException(UserError::class, 'Persisted queries are not supported by this server');
+        $this->executePersistedQuery('some-id');
+    }
+
+    public function testAllowsPersistentQueries()
+    {
+        $called = false;
+        $this->config->setPersistentQueryLoader(function($queryId, OperationParams $params) use (&$called) {
+            $called = true;
+            $this->assertEquals('some-id', $queryId);
+            return '{f1}';
+        });
+
+        $result = $this->executePersistedQuery('some-id');
+        $this->assertTrue($called);
+
+        $expected = [
+            'data' => [
+                'f1' => 'f1'
+            ]
+        ];
+        $this->assertEquals($expected, $result->toArray());
+
+        // Make sure it allows returning document node:
+        $called = false;
+        $this->config->setPersistentQueryLoader(function($queryId, OperationParams $params) use (&$called) {
+            $called = true;
+            $this->assertEquals('some-id', $queryId);
+            return Parser::parse('{f1}');
+        });
+        $result = $this->executePersistedQuery('some-id');
+        $this->assertTrue($called);
+        $this->assertEquals($expected, $result->toArray());
+    }
+
+    public function testPersistedQueriesAreStillValidatedByDefault()
+    {
+        $this->config->setPersistentQueryLoader(function() {
+            return '{invalid}';
+        });
+        $result = $this->executePersistedQuery('some-id');
+        $expected = [
+            'errors' => [
+                [
+                    'message' => 'Cannot query field "invalid" on type "Query".',
+                    'locations' => [ ['line' => 1, 'column' => 2] ]
+                ]
+            ]
+        ];
+        $this->assertEquals($expected, $result->toArray());
+
+    }
+
+    public function testAllowSkippingValidationForPersistedQueries()
+    {
+        $this->config
+            ->setPersistentQueryLoader(function($queryId) {
+                if ($queryId === 'some-id') {
+                    return '{invalid}';
+                } else {
+                    return '{invalid2}';
+                }
+            })
+            ->setValidationRules(function(OperationParams $params) {
+                if ($params->queryId === 'some-id') {
+                    return [];
+                } else {
+                    return DocumentValidator::allRules();
+                }
+            });
+
+        $result = $this->executePersistedQuery('some-id');
+        $expected = [
+            'data' => []
+        ];
+        $this->assertEquals($expected, $result->toArray());
+
+        $result = $this->executePersistedQuery('some-other-id');
+        $expected = [
+            'errors' => [
+                [
+                    'message' => 'Cannot query field "invalid2" on type "Query".',
+                    'locations' => [ ['line' => 1, 'column' => 2] ]
+                ]
+            ]
+        ];
+        $this->assertEquals($expected, $result->toArray());
+    }
+
+    private function executePersistedQuery($queryId, $variables = null)
+    {
+        $op = OperationParams::create(['queryId' => $queryId, 'variables' => $variables]);
+        $result = Helper::executeOperation($this->config, $op);
+        $this->assertInstanceOf(ExecutionResult::class, $result);
+        return $result;
+    }
+
+    private function executeQuery($query, $variables = null)
+    {
+        $op = OperationParams::create(['query' => $query, 'variables' => $variables]);
+
+        $result = Helper::executeOperation($this->config, $op);
+        $this->assertInstanceOf(ExecutionResult::class, $result);
+        return $result;
+    }
+
+    private function assertQueryResultEquals($expected, $query, $variables = null)
+    {
+        $result = $this->executeQuery($query, $variables);
+        $this->assertArraySubset($expected, $result->toArray());
+        return $result;
+    }
+}
diff --git a/tests/Server/ServerConfigTest.php b/tests/Server/ServerConfigTest.php
new file mode 100644
index 0000000..c7f4c24
--- /dev/null
+++ b/tests/Server/ServerConfigTest.php
@@ -0,0 +1,144 @@
+<?php
+namespace GraphQL\Tests\Server;
+
+use GraphQL\Error\FormattedError;
+use GraphQL\Executor\Promise\Adapter\SyncPromiseAdapter;
+use GraphQL\Schema;
+use GraphQL\Server\ServerConfig;
+use GraphQL\Type\Definition\ObjectType;
+
+class ServerConfigTest extends \PHPUnit_Framework_TestCase
+{
+    public function testDefaults()
+    {
+        $config = ServerConfig::create();
+        $this->assertEquals(null, $config->getSchema());
+        $this->assertEquals(null, $config->getContext());
+        $this->assertEquals(null, $config->getRootValue());
+        $this->assertEquals([FormattedError::class, 'createFromException'], $config->getErrorFormatter());
+        $this->assertEquals(null, $config->getPromiseAdapter());
+        $this->assertEquals(null, $config->getValidationRules());
+        $this->assertEquals(null, $config->getDefaultFieldResolver());
+        $this->assertEquals(null, $config->getPersistentQueryLoader());
+        $this->assertEquals(false, $config->getDebug());
+    }
+
+    public function testAllowsSettingSchema()
+    {
+        $schema = new Schema(['query' => new ObjectType(['name' => 'a', 'fields' => []])]);
+        $config = ServerConfig::create()
+            ->setSchema($schema);
+
+        $this->assertSame($schema, $config->getSchema());
+
+        $schema2 = new Schema(['query' => new ObjectType(['name' => 'a', 'fields' => []])]);
+        $config->setSchema($schema2);
+        $this->assertSame($schema2, $config->getSchema());
+    }
+
+    public function testAllowsSettingContext()
+    {
+        $config = ServerConfig::create();
+
+        $context = [];
+        $config->setContext($context);
+        $this->assertSame($context, $config->getContext());
+
+        $context2 = new \stdClass();
+        $config->setContext($context2);
+        $this->assertSame($context2, $config->getContext());
+    }
+
+    public function testAllowsSettingRootValue()
+    {
+        $config = ServerConfig::create();
+
+        $rootValue = [];
+        $config->setRootValue($rootValue);
+        $this->assertSame($rootValue, $config->getRootValue());
+
+        $context2 = new \stdClass();
+        $config->setRootValue($context2);
+        $this->assertSame($context2, $config->getRootValue());
+    }
+
+    public function testAllowsSettingErrorFormatter()
+    {
+        $config = ServerConfig::create();
+
+        $formatter = function() {};
+        $config->setErrorFormatter($formatter);
+        $this->assertSame($formatter, $config->getErrorFormatter());
+
+        $formatter = 'date'; // test for callable
+        $config->setErrorFormatter($formatter);
+        $this->assertSame($formatter, $config->getErrorFormatter());
+    }
+
+    public function testAllowsSettingPromiseAdapter()
+    {
+        $config = ServerConfig::create();
+
+        $adapter1 = new SyncPromiseAdapter();
+        $config->setPromiseAdapter($adapter1);
+        $this->assertSame($adapter1, $config->getPromiseAdapter());
+
+        $adapter2 = new SyncPromiseAdapter();
+        $config->setPromiseAdapter($adapter2);
+        $this->assertSame($adapter2, $config->getPromiseAdapter());
+    }
+
+    public function testAllowsSettingValidationRules()
+    {
+        $config = ServerConfig::create();
+
+        $rules = [];
+        $config->setValidationRules($rules);
+        $this->assertSame($rules, $config->getValidationRules());
+
+        $rules = [function() {}];
+        $config->setValidationRules($rules);
+        $this->assertSame($rules, $config->getValidationRules());
+
+        $rules = function() {return [function() {}];};
+        $config->setValidationRules($rules);
+        $this->assertSame($rules, $config->getValidationRules());
+    }
+
+    public function testAllowsSettingDefaultFieldResolver()
+    {
+        $config = ServerConfig::create();
+
+        $resolver = function() {};
+        $config->setDefaultFieldResolver($resolver);
+        $this->assertSame($resolver, $config->getDefaultFieldResolver());
+
+        $resolver = 'date'; // test for callable
+        $config->setDefaultFieldResolver($resolver);
+        $this->assertSame($resolver, $config->getDefaultFieldResolver());
+    }
+
+    public function testAllowsSettingPersistedQueryLoader()
+    {
+        $config = ServerConfig::create();
+
+        $loader = function() {};
+        $config->setPersistentQueryLoader($loader);
+        $this->assertSame($loader, $config->getPersistentQueryLoader());
+
+        $loader = 'date'; // test for callable
+        $config->setPersistentQueryLoader($loader);
+        $this->assertSame($loader, $config->getPersistentQueryLoader());
+    }
+
+    public function testAllowsSettingCatchPhpErrors()
+    {
+        $config = ServerConfig::create();
+
+        $config->setDebug(true);
+        $this->assertSame(true, $config->getDebug());
+
+        $config->setDebug(false);
+        $this->assertSame(false, $config->getDebug());
+    }
+}
diff --git a/tests/ServerTest.php b/tests/ServerTest.php
deleted file mode 100644
index 27d4753..0000000
--- a/tests/ServerTest.php
+++ /dev/null
@@ -1,580 +0,0 @@
-<?php
-namespace GraphQL\Tests;
-
-use GraphQL\Error\Error;
-use GraphQL\Error\InvariantViolation;
-use GraphQL\Executor\ExecutionResult;
-use GraphQL\Executor\Promise\Adapter\SyncPromiseAdapter;
-use GraphQL\Schema;
-use GraphQL\Server;
-use GraphQL\Type\Definition\Directive;
-use GraphQL\Type\Definition\ObjectType;
-use GraphQL\Type\Definition\ResolveInfo;
-use GraphQL\Type\Definition\Type;
-use GraphQL\Type\EagerResolution;
-use GraphQL\Validator\DocumentValidator;
-
-class ServerTest extends \PHPUnit_Framework_TestCase
-{
-    public function testDefaults()
-    {
-        $server = new Server();
-        $this->assertEquals(null, $server->getQueryType());
-        $this->assertEquals(null, $server->getMutationType());
-        $this->assertEquals(null, $server->getSubscriptionType());
-        $this->assertEquals(Directive::getInternalDirectives(), $server->getDirectives());
-        $this->assertEquals([], $server->getTypes());
-        $this->assertEquals(null, $server->getTypeResolutionStrategy());
-
-        $this->assertEquals(null, $server->getContext());
-        $this->assertEquals(null, $server->getRootValue());
-        $this->assertEquals(0, $server->getDebug());
-
-        $this->assertEquals(['GraphQL\Error\FormattedError', 'createFromException'], $server->getExceptionFormatter());
-        $this->assertEquals(['GraphQL\Error\FormattedError', 'createFromPHPError'], $server->getPhpErrorFormatter());
-        $this->assertEquals(null, $server->getPromiseAdapter());
-        $this->assertEquals('Unexpected Error', $server->getUnexpectedErrorMessage());
-        $this->assertEquals(500, $server->getUnexpectedErrorStatus());
-        $this->assertEquals(DocumentValidator::allRules(), $server->getValidationRules());
-
-        try {
-            $server->getSchema();
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals('Schema query must be Object Type but got: NULL', $e->getMessage());
-        }
-    }
-
-    public function testSchemaDefinition()
-    {
-        $mutationType = $queryType = $subscriptionType = new ObjectType(['name' => 'A', 'fields' => []]);
-
-        $schema = new Schema([
-            'query' => $queryType
-        ]);
-
-        try {
-            Server::create()
-                ->setQueryType($queryType)
-                ->setSchema($schema);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Schema on Server: Query Type is already set '.
-                '(GraphQL\Server::setQueryType is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setMutationType($mutationType)
-                ->setSchema($schema);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Schema on Server: Mutation Type is already set '.
-                '(GraphQL\Server::setMutationType is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setSubscriptionType($subscriptionType)
-                ->setSchema($schema);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Schema on Server: Subscription Type is already set '.
-                '(GraphQL\Server::setSubscriptionType is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setDirectives(Directive::getInternalDirectives())
-                ->setSchema($schema);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Schema on Server: Directives are already set '.
-                '(GraphQL\Server::setDirectives is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->addTypes([$queryType, $mutationType])
-                ->setSchema($schema);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Schema on Server: Additional types are already set '.
-                '(GraphQL\Server::addTypes is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-
-        try {
-            Server::create()
-                ->setTypeResolutionStrategy(new EagerResolution([$queryType, $mutationType]))
-                ->setSchema($schema);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Schema on Server: Type Resolution Strategy is already set '.
-                '(GraphQL\Server::setTypeResolutionStrategy is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setSchema($schema)
-                ->setQueryType($queryType);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Query Type on Server: Schema is already set '.
-                '(GraphQL\Server::setQueryType is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setSchema($schema)
-                ->setMutationType($mutationType);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Mutation Type on Server: Schema is already set '.
-                '(GraphQL\Server::setMutationType is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setSchema($schema)
-                ->setSubscriptionType($subscriptionType);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Subscription Type on Server: Schema is already set '.
-                '(GraphQL\Server::setSubscriptionType is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setSchema($schema)
-                ->setDirectives([]);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Directives on Server: Schema is already set '.
-                '(GraphQL\Server::setDirectives is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setSchema($schema)
-                ->addTypes([$queryType, $mutationType]);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Types on Server: Schema is already set '.
-                '(GraphQL\Server::addTypes is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-        // But empty types should work (as they don't change anything):
-        Server::create()
-            ->setSchema($schema)
-            ->addTypes([]);
-
-        try {
-            Server::create()
-                ->setSchema($schema)
-                ->setTypeResolutionStrategy(new EagerResolution([$queryType, $mutationType]));
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Type Resolution Strategy on Server: Schema is already set '.
-                '(GraphQL\Server::setTypeResolutionStrategy is mutually exclusive with GraphQL\Server::setSchema)',
-                $e->getMessage()
-            );
-        }
-
-        try {
-            Server::create()
-                ->setSchema($schema)
-                ->setSchema(new Schema(['query' => $queryType]));
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set Schema on Server: Different schema is already set',
-                $e->getMessage()
-            );
-        }
-
-
-        // This should not throw:
-        $server = Server::create()
-            ->setSchema($schema);
-
-        $this->assertSame($schema, $server->getSchema());
-
-        $server = Server::create()
-            ->setQueryType($queryType);
-        $this->assertSame($queryType, $server->getQueryType());
-        $this->assertSame($queryType, $server->getSchema()->getQueryType());
-
-        $server = Server::create()
-            ->setQueryType($queryType)
-            ->setMutationType($mutationType);
-
-        $this->assertSame($mutationType, $server->getMutationType());
-        $this->assertSame($mutationType, $server->getSchema()->getMutationType());
-
-        $server = Server::create()
-            ->setQueryType($queryType)
-            ->setSubscriptionType($subscriptionType);
-
-        $this->assertSame($subscriptionType, $server->getSubscriptionType());
-        $this->assertSame($subscriptionType, $server->getSchema()->getSubscriptionType());
-
-        $server = Server::create()
-            ->setQueryType($queryType)
-            ->addTypes($types = [$queryType, $subscriptionType]);
-
-        $this->assertSame($types, $server->getTypes());
-        $server->addTypes([$mutationType]);
-        $this->assertSame(array_merge($types, [$mutationType]), $server->getTypes());
-
-        $server = Server::create()
-            ->setDirectives($directives = []);
-
-        $this->assertSame($directives, $server->getDirectives());
-    }
-
-    public function testParse()
-    {
-        $server = Server::create();
-        $ast = $server->parse('{q}');
-        $this->assertInstanceOf('GraphQL\Language\AST\DocumentNode', $ast);
-
-        try {
-            $server->parse('{q');
-            $this->fail('Expected exception not thrown');
-        } catch (\GraphQL\Error\SyntaxError $e) {
-            $this->assertContains('{q', $e->getMessage());
-        }
-    }
-
-    public function testValidate()
-    {
-        $server = Server::create()
-            ->setQueryType(new ObjectType(['name' => 'Q', 'fields' => []]));
-
-        $ast = $server->parse('{q}');
-        $errors = $server->validate($ast);
-
-        $this->assertInternalType('array', $errors);
-        $this->assertNotEmpty($errors);
-
-        try {
-            $server = Server::create();
-            $server->validate($ast);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot validate, schema contains errors: Schema query must be Object Type but got: NULL',
-                $e->getMessage()
-            );
-        }
-    }
-
-    public function testPromiseAdapter()
-    {
-        $adapter1 = new SyncPromiseAdapter();
-        $adapter2 = new SyncPromiseAdapter();
-
-        $server = Server::create()
-            ->setPromiseAdapter($adapter1);
-
-        $this->assertSame($adapter1, $server->getPromiseAdapter());
-        $server->setPromiseAdapter($adapter1);
-
-        try {
-            $server->setPromiseAdapter($adapter2);
-            $this->fail('Expected exception not thrown');
-        } catch (InvariantViolation $e) {
-            $this->assertEquals(
-                'Cannot set promise adapter: Different adapter is already set',
-                $e->getMessage()
-            );
-        }
-    }
-
-    public function testValidationRules()
-    {
-        $rules = [];
-        $server = Server::create()
-            ->setValidationRules($rules);
-
-        $this->assertSame($rules, $server->getValidationRules());
-    }
-
-    public function testExecuteQuery()
-    {
-        $called = false;
-        $queryType = new ObjectType([
-            'name' => 'Q',
-            'fields' => [
-                'field' => [
-                    'type' => Type::string(),
-                    'resolve' => function($value, $args, $context, ResolveInfo $info) use (&$called) {
-                        $called = true;
-                        $this->assertEquals(null, $context);
-                        $this->assertEquals(null, $value);
-                        $this->assertEquals(null, $info->rootValue);
-                        return 'ok';
-                    }
-                ]
-            ]
-        ]);
-
-        $server = Server::create()
-            ->setQueryType($queryType);
-
-        $result = $server->executeQuery('{field}');
-        $this->assertEquals(true, $called);
-        $this->assertInstanceOf('GraphQL\Executor\ExecutionResult', $result);
-        $this->assertEquals(['data' => ['field' => 'ok']], $result->toArray());
-
-        $called = false;
-        $contextValue = new \stdClass();
-        $rootValue = new \stdClass();
-
-        $queryType = new ObjectType([
-            'name' => 'QueryType',
-            'fields' => [
-                'field' => [
-                    'type' => Type::string(),
-                    'resolve' => function($value, $args, $context, ResolveInfo $info) use (&$called, $contextValue, $rootValue) {
-                        $called = true;
-                        $this->assertSame($rootValue, $value);
-                        $this->assertSame($contextValue, $context);
-                        $this->assertEquals($rootValue, $info->rootValue);
-                        return 'ok';
-                    }
-                ]
-            ]
-        ]);
-
-        $server = Server::create()
-            ->setQueryType($queryType)
-            ->setRootValue($rootValue)
-            ->setContext($contextValue);
-
-        $result = $server->executeQuery('{field}');
-        $this->assertEquals(true, $called);
-        $this->assertInstanceOf('GraphQL\Executor\ExecutionResult', $result);
-        $this->assertEquals(['data' => ['field' => 'ok']], $result->toArray());
-    }
-
-    public function testDebugPhpErrors()
-    {
-        $queryType = new ObjectType([
-            'name' => 'Query',
-            'fields' => [
-                'err' => [
-                    'type' => Type::string(),
-                    'resolve' => function() {
-                        trigger_error('notice', E_USER_NOTICE);
-                        return 'err';
-                    }
-                ]
-            ]
-        ]);
-
-        $server = Server::create()
-            ->setDebug(0)
-            ->setQueryType($queryType);
-
-        $prevEnabled = \PHPUnit_Framework_Error_Notice::$enabled;
-        \PHPUnit_Framework_Error_Notice::$enabled = false;
-        $result = @$server->executeQuery('{err}');
-
-        $expected = [
-            'data' => ['err' => 'err']
-        ];
-        $this->assertEquals($expected, $result->toArray());
-
-        $server->setDebug(Server::DEBUG_PHP_ERRORS);
-        $result = @$server->executeQuery('{err}');
-
-        $expected = [
-            'data' => ['err' => 'err'],
-            'extensions' => [
-                'phpErrors' => [
-                    [
-                        'message' => 'notice',
-                        'severity' => 1024,
-                        // 'trace' => [...]
-                    ]
-                ]
-            ]
-        ];
-
-        $this->assertArraySubset($expected, $result->toArray());
-
-        $server->setPhpErrorFormatter(function(\ErrorException $e) {
-            return ['test' => $e->getMessage()];
-        });
-
-        $result = $server->executeQuery('{err}');
-        $expected = [
-            'data' => ['err' => 'err'],
-            'extensions' => [
-                'phpErrors' => [
-                    [
-                        'test' => 'notice'
-                    ]
-                ]
-            ]
-        ];
-        $this->assertEquals($expected, $result->toArray());
-
-        \PHPUnit_Framework_Error_Notice::$enabled = $prevEnabled;
-    }
-
-    public function testDebugExceptions()
-    {
-        $queryType = new ObjectType([
-            'name' => 'Query',
-            'fields' => [
-                'withException' => [
-                    'type' => Type::string(),
-                    'resolve' => function() {
-                        throw new \Exception("Error");
-                    }
-                ]
-            ]
-        ]);
-
-        $server = Server::create()
-            ->setDebug(0)
-            ->setQueryType($queryType);
-
-        $result = $server->executeQuery('{withException}');
-        $expected = [
-            'data' => [
-                'withException' => null
-            ],
-            'errors' => [[
-                'message' => 'Error',
-                'path' => ['withException'],
-                'locations' => [[
-                    'line' => 1,
-                    'column' => 2
-                ]]
-            ]]
-        ];
-        $this->assertEquals($expected, $result->toArray());
-
-        $server->setDebug(Server::DEBUG_EXCEPTIONS);
-        $result = $server->executeQuery('{withException}');
-
-        $expected['errors'][0]['exception'] = ['message' => 'Error', 'trace' => []];
-        $this->assertArraySubset($expected, $result->toArray());
-
-        $server->setExceptionFormatter(function(\Exception $e) {
-            return ['test' => $e->getMessage()];
-        });
-
-        $result = $server->executeQuery('{withException}');
-        $expected['errors'][0]['exception'] = ['test' => 'Error'];
-        $this->assertEquals($expected, $result->toArray());
-    }
-
-    public function testHandleRequest()
-    {
-        $mock = $this->getMockBuilder('GraphQL\Server')
-            ->setMethods(['readInput', 'produceOutput'])
-            ->getMock()
-        ;
-
-        $mock->method('readInput')
-            ->will($this->returnValue(json_encode(['query' => '{err}'])));
-
-        $output = null;
-        $mock->method('produceOutput')
-            ->will($this->returnCallback(function($a1, $a2) use (&$output) {
-                $output = func_get_args();
-            }));
-
-        /** @var $mock Server */
-        $mock->handleRequest();
-
-        $this->assertInternalType('array', $output);
-        $this->assertEquals(['errors' => [['message' => 'Unexpected Error']]], $output[0]);
-        $this->assertEquals(500, $output[1]);
-
-        $output = null;
-        $mock->setUnexpectedErrorMessage($newErr = 'Hey! Something went wrong!');
-        $mock->setUnexpectedErrorStatus(501);
-        $mock->handleRequest();
-
-        $this->assertInternalType('array', $output);
-        $this->assertEquals(['errors' => [['message' => $newErr]]], $output[0]);
-        $this->assertEquals(501, $output[1]);
-
-        $mock->setQueryType(new ObjectType([
-            'name' => 'Query',
-            'fields' => [
-                'test' => [
-                    'type' => Type::string(),
-                    'resolve' => function() {
-                        return 'ok';
-                    }
-                ]
-            ]
-        ]));
-
-        $_REQUEST = ['query' => '{err}'];
-        $output = null;
-        $mock->handleRequest();
-        $this->assertInternalType('array', $output);
-
-        $expectedOutput = [
-            ['errors' => [[
-                'message' => 'Cannot query field "err" on type "Query".',
-                'locations' => [[
-                    'line' => 1,
-                    'column' => 2
-                ]]
-            ]]],
-            200
-        ];
-
-        $this->assertEquals($expectedOutput, $output);
-
-        $output = null;
-        $_SERVER['CONTENT_TYPE'] = 'application/json';
-        $_REQUEST = [];
-        $mock->handleRequest();
-
-        $this->assertInternalType('array', $output);
-        $this->assertEquals($expectedOutput, $output);
-    }
-}