Add support for types and improve resolution

As part of the re-architecting of phpDocumentor and its Reflection component
we needed to move the type classes from the \phpDocumentor\Descriptor
namespace to \phpDocumentor\Reflection\Types.

In addition to this I have removed the resolution / type creation from the
Collection class into a new Resolver class that is capable of resolving any
type into a Type or Fqsen object.

This is the first commit with the base classes and a test for the Resolver
functionality in subsequent commits we need to add tests for the other
classes and to refactor the collection object.

src/Type.php

@@ -0,0 +1,18 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection;
+
+interface Type
+{
+    public function __toString();
+}

src/Types/Array_.php

@@ -0,0 +1,63 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+class Array_ implements Type
+{
+    /** @var Type */
+    private $valueType;
+
+    /** @var Type */
+    private $keyType;
+
+    public function __construct(Type $valueType = null, Type $keyType = null)
+    {
+        if ($keyType === null) {
+            $keyType = new Mixed();
+        }
+        if ($valueType === null) {
+            $valueType = new Mixed();
+        }
+
+        $this->valueType = $valueType;
+        $this->keyType = $keyType;
+    }
+
+    /**
+     * @return Type
+     */
+    public function getKeyType()
+    {
+        return $this->keyType;
+    }
+
+    /**
+     * @return Type
+     */
+    public function getValueType()
+    {
+        return $this->valueType;
+    }
+
+    public function __toString()
+    {
+        if ($this->valueType instanceof Mixed) {
+            return 'array';
+        }
+
+        return $this->valueType . '[]';
+    }
+}

src/Types/Boolean.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Boolean implements Type
+{
+    public function __toString()
+    {
+        return 'bool';
+    }
+}

src/Types/Callable_.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Callable_ implements Type
+{
+    public function __toString()
+    {
+        return 'callable';
+    }
+}

src/Types/Collection.php

@@ -0,0 +1,113 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Types\Resolver;
+use phpDocumentor\Reflection\DocBlock\Context;
+
+/**
+ * Collection
+ */
+class Collection extends \ArrayObject
+{
+    /** @var string Definition of the OR operator for types */
+    const OPERATOR_OR = '|';
+
+    /**
+     * Current invoking location.
+     *
+     * This is used to prepend to type with a relative location.
+     * May also be 'default' or 'global', in which case they are ignored.
+     *
+     * @var Context
+     */
+    protected $context = null;
+    /**
+     * @var Resolver
+     */
+    private $resolver;
+
+    /**
+     * Registers the namespace and aliases; uses that to add and expand the given types.
+     *
+     * @param string[] $types Array containing a list of types to add to this container.
+     * @param Context $context
+     * @param Resolver $resolver
+     */
+    public function __construct(array $types = array(), Context $context = null, Resolver $resolver = null)
+    {
+        $this->context = $context ?: new Context('');
+        $this->resolver = $resolver ?: new Resolver();
+
+        foreach ($types as $type) {
+            $this->add($type);
+        }
+    }
+
+    /**
+     * Returns the current invoking location.
+     *
+     * @return Context
+     */
+    public function getContext()
+    {
+        return $this->context;
+    }
+
+    /**
+     * Adds a new type to the collection and expands it if it contains a
+     * relative namespace.
+     *
+     * If a class in the type contains a relative namespace than this collection
+     * will try to expand that into a FQCN.
+     *
+     * @param string $type A 'Type' as defined in the phpDocumentor
+     *     documentation.
+     *
+     * @throws \InvalidArgumentException if a non-string argument is passed.
+     *
+     * @see http://phpdoc.org/docs/latest/for-users/types.html for the
+     *     definition of a type.
+     *
+     * @return void
+     */
+    public function add($type)
+    {
+        if (!is_string($type)) {
+            throw new \InvalidArgumentException(
+                'A type should be represented by a string, received: '
+                . var_export($type, true)
+            );
+        }
+
+        // separate the type by the OR operator
+        $type_parts = explode(self::OPERATOR_OR, $type);
+        foreach ($type_parts as $part) {
+            $expanded_type = $this->resolver->resolve($part, $this->context);
+            if ($expanded_type) {
+                $this[] = $expanded_type;
+            }
+        }
+    }
+
+    /**
+     * Returns a string representation of the collection.
+     *
+     * @return string The resolved types across the collection, separated with
+     *     {@link self::OPERATOR_OR}.
+     */
+    public function __toString()
+    {
+        return implode(self::OPERATOR_OR, $this->getArrayCopy());
+    }
+}

src/Types/Compound.php

@@ -0,0 +1,60 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Fqsen;
+use phpDocumentor\Reflection\Type;
+
+final class Compound implements Type
+{
+    /** @var Type[] */
+    private $types = [];
+
+    /**
+     * @param Type[]|Fqsen[] $types
+     */
+    public function __construct($types)
+    {
+        $this->types = $types;
+    }
+
+    /**
+     * @param integer $index
+     *
+     * @return null|Type|Fqsen
+     */
+    public function get($index)
+    {
+        if (!$this->has($index)) {
+            return null;
+        }
+
+        return $this->types[$index];
+    }
+
+    /**
+     * @param integer $index
+     *
+     * @return bool
+     */
+    public function has($index)
+    {
+        return isset($this->types[$index]);
+    }
+
+    public function __toString()
+    {
+        return implode('|', $this->types);
+    }
+}

src/Types/Float.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Float implements Type
+{
+    public function __toString()
+    {
+        return 'float';
+    }
+}

src/Types/Integer.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Integer implements Type
+{
+    public function __toString()
+    {
+        return 'int';
+    }
+}

src/Types/Mixed.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Mixed implements Type
+{
+    public function __toString()
+    {
+        return 'mixed';
+    }
+}

src/Types/Null_.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Null_ implements Type
+{
+    public function __toString()
+    {
+        return 'null';
+    }
+}

src/Types/Object_.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Object_ implements Type
+{
+    public function __toString()
+    {
+        return 'object';
+    }
+}

src/Types/Resolver.php

@@ -0,0 +1,251 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\DocBlock\Context;
+use phpDocumentor\Reflection\Fqsen;
+use phpDocumentor\Reflection\Type;
+
+class Resolver
+{
+    /** @var string Definition of the ARRAY operator for types */
+    const OPERATOR_ARRAY = '[]';
+
+    /** @var string Definition of the NAMESPACE operator in PHP */
+    const OPERATOR_NAMESPACE = '\\';
+
+    /** @var string[] List of recognized keywords and unto which Value Object they map */
+    private $keywords = array(
+        'string' => 'phpDocumentor\Reflection\Types\String',
+        'int' => 'phpDocumentor\Reflection\Types\Integer',
+        'integer' => 'phpDocumentor\Reflection\Types\Integer',
+        'bool' => 'phpDocumentor\Reflection\Types\Boolean',
+        'boolean' => 'phpDocumentor\Reflection\Types\Boolean',
+        'float' => 'phpDocumentor\Reflection\Types\Float',
+        'double' => 'phpDocumentor\Reflection\Types\Float',
+        'object' => 'phpDocumentor\Reflection\Types\Object_',
+        'mixed' => 'phpDocumentor\Reflection\Types\Mixed',
+        'array' => 'phpDocumentor\Reflection\Types\Array_',
+        'resource' => 'phpDocumentor\Reflection\Types\Resource',
+        'void' => 'phpDocumentor\Reflection\Types\Void',
+        'null' => 'phpDocumentor\Reflection\Types\Null_',
+        'scalar' => 'phpDocumentor\Reflection\Types\Scalar',
+        'callback' => 'phpDocumentor\Reflection\Types\Callable_',
+        'callable' => 'phpDocumentor\Reflection\Types\Callable_',
+        'false' => 'phpDocumentor\Reflection\Types\Boolean',
+        'true' => 'phpDocumentor\Reflection\Types\Boolean',
+        'self' => 'phpDocumentor\Reflection\Types\Self_',
+        '$this' => 'phpDocumentor\Reflection\Types\This',
+        'static' => 'phpDocumentor\Reflection\Types\Static_'
+    );
+
+    /**
+     * Analyzes the given type and returns the FQCN variant.
+     *
+     * When a type is provided this method checks whether it is not a keyword or
+     * Fully Qualified Class Name. If so it will use the given namespace and
+     * aliases to expand the type to a FQCN representation.
+     *
+     * This method only works as expected if the namespace and aliases are set;
+     * no dynamic reflection is being performed here.
+     *
+     * @param string $type The relative or absolute type.
+     *
+     * @uses Context::getNamespace()        to determine with what to prefix the type name.
+     * @uses Context::getNamespaceAliases() to check whether the first part of the relative type name should not be
+     *     replaced with another namespace.
+     *
+     * @return Fqsen|Type|null
+     */
+    public function resolve($type, Context $context)
+    {
+        if (!is_string($type)) {
+            throw new \InvalidArgumentException(
+                'Attempted to resolve type but it appeared not to be a string, received: ' . var_export($type, true)
+            );
+        }
+
+        $type = trim($type);
+        if (!$type) {
+            throw new \InvalidArgumentException('Attempted to resolve "' . $type . '" but it appears to be empty');
+        }
+
+        switch (true) {
+            case $this->isKeyword($type):
+                return $this->resolveKeyword($type);
+            case ($this->isCompoundType($type)):
+                return $this->resolveCompoundType($type, $context);
+            case $this->isFqsen($type):
+                return $this->resolveFqsen($type);
+            case $this->isTypedArray($type):
+                return $this->resolveTypedArray($type, $context);
+            case $this->isPartialStructuralElementName($type):
+                return $this->resolvePartialStructuralElementName($type, $context);
+            // @codeCoverageIgnoreStart
+            default:
+                // I haven't got the foggiest how the logic would come here but added this as a defense.
+                throw new \RuntimeException(
+                    'Unable to resolve type "' . $type . '", there is no known method to resolve it'
+                );
+        }
+        // @codeCoverageIgnoreEnd
+    }
+
+    /**
+     * Detects whether the given type represents an array.
+     *
+     * @param string $type A relative or absolute type as defined in the phpDocumentor documentation.
+     *
+     * @return bool
+     */
+    private function isTypedArray($type)
+    {
+        return substr($type, -2) === self::OPERATOR_ARRAY;
+    }
+
+    /**
+     * Detects whether the given type represents a PHPDoc keyword.
+     *
+     * @param string $type A relative or absolute type as defined in the phpDocumentor documentation.
+     *
+     * @return bool
+     */
+    private function isKeyword($type)
+    {
+        return in_array(strtolower($type), array_keys($this->keywords), true);
+    }
+
+    /**
+     * Detects whether the given type represents a relative structural element name.
+     *
+     * @param string $type A relative or absolute type as defined in the phpDocumentor documentation.
+     *
+     * @return bool
+     */
+    private function isPartialStructuralElementName($type)
+    {
+        return ($type[0] !== self::OPERATOR_NAMESPACE) && !$this->isKeyword($type);
+    }
+
+    /**
+     * Tests whether the given type is a Fully Qualified Structural Element Name.
+     *
+     * @param string $type
+     *
+     * @return bool
+     */
+    private function isFqsen($type)
+    {
+        return strpos($type, self::OPERATOR_NAMESPACE) === 0;
+    }
+
+    /**
+     * Tests whether the given type is a compound type (i.e. `string|int`).
+     *
+     * @param string $type
+     *
+     * @return bool
+     */
+    private function isCompoundType($type)
+    {
+        return strpos($type, '|') !== false;
+    }
+
+    /**
+     * Resolves the given typed array string (i.e. `string[]`) into an Array object with the right types set.
+     *
+     * @param string $type
+     * @param Context $context
+     *
+     * @return Array_
+     */
+    private function resolveTypedArray($type, Context $context)
+    {
+        return new Array_($this->resolve(substr($type, 0, -2), $context));
+    }
+
+    /**
+     * Resolves the given keyword (such as `string`) into a Type object representing that keyword.
+     *
+     * @param string $type
+     *
+     * @return Type
+     */
+    private function resolveKeyword($type)
+    {
+        $className = $this->keywords[strtolower($type)];
+
+        return new $className();
+    }
+
+    /**
+     * Resolves the given FQSEN string into an FQSEN object.
+     *
+     * @param string $type
+     *
+     * @return Fqsen
+     */
+    private function resolveFqsen($type)
+    {
+        return new Fqsen($type);
+    }
+
+    /**
+     * Resolves a partial Structural Element Name (i.e. `Reflection\DocBlock`) to its FQSEN representation
+     * (i.e. `\phpDocumentor\Reflection\DocBlock`) based on the Namespace and aliases mentioned in the Context.
+     *
+     * @param string $type
+     * @param Context $context
+     *
+     * @return Fqsen
+     */
+    private function resolvePartialStructuralElementName($type, Context $context)
+    {
+        $typeParts = explode(self::OPERATOR_NAMESPACE, $type, 2);
+
+        $namespaceAliases = $context->getNamespaceAliases();
+
+        // if the first segment is not an alias; prepend namespace name and return
+        if (!isset($namespaceAliases[$typeParts[0]])) {
+            $namespace = $context->getNamespace();
+            if ('' !== $namespace) {
+                $namespace .= self::OPERATOR_NAMESPACE;
+            }
+
+            return new Fqsen(self::OPERATOR_NAMESPACE . $namespace . $type);
+        }
+
+        $typeParts[0] = $namespaceAliases[$typeParts[0]];
+
+        return new Fqsen(self::OPERATOR_NAMESPACE . implode(self::OPERATOR_NAMESPACE, $typeParts));
+    }
+
+    /**
+     * Resolves a compound type (i.e. `string|int`) into the appropriate Type objects or FQSEN.
+     *
+     * @param string $type
+     * @param Context $context
+     *
+     * @return Compound
+     */
+    private function resolveCompoundType($type, Context $context)
+    {
+        $types = [];
+
+        foreach (explode('|', $type) as $part) {
+            $types[] = $this->resolve($part, $context);
+        }
+
+        return new Compound($types);
+    }
+}

src/Types/Resource.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Resource implements Type
+{
+    public function __toString()
+    {
+        return 'resource';
+    }
+}

src/Types/Scalar.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+class Scalar implements Type
+{
+    public function __toString()
+    {
+        return 'scalar';
+    }
+}

src/Types/Self_.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Self_ implements Type
+{
+    public function __toString()
+    {
+        return 'self';
+    }
+}

src/Types/Static_.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Static_ implements Type
+{
+    public function __toString()
+    {
+        return 'static';
+    }
+}

src/Types/String.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class String implements Type
+{
+    public function __toString()
+    {
+        return 'string';
+    }
+}

src/Types/This.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class This implements Type
+{
+    public function __toString()
+    {
+        return '$this';
+    }
+}

src/Types/Void.php

@@ -0,0 +1,23 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\Type;
+
+final class Void implements Type
+{
+    public function __toString()
+    {
+        return 'void';
+    }
+}

tests/phpDocumentor/Reflection/Types/ResolverTest.php

@@ -0,0 +1,235 @@
+<?php
+/**
+ * This file is part of phpDocumentor.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright 2010-2015 Mike van Riel<[email protected]>
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT
+ * @link      http://phpdoc.org
+ */
+
+namespace phpDocumentor\Reflection\Types;
+
+use phpDocumentor\Reflection\DocBlock\Context;
+
+/**
+ * @coversDefaultClass phpDocumentor\Reflection\Types\Resolver
+ */
+class ResolverTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @param string $keyword
+     * @param string $expectedClass
+     *
+     * @covers ::resolve
+     * @covers ::<private>
+     *
+     * @uses         phpDocumentor\Reflection\DocBlock\Context
+     * @uses         phpDocumentor\Reflection\Types\Array_
+     *
+     * @dataProvider provideKeywords
+     */
+    public function testResolvingKeywords($keyword, $expectedClass)
+    {
+        $fixture = new Resolver();
+
+        $resolvedType = $fixture->resolve($keyword, new Context(''));
+
+        $this->assertInstanceOf($expectedClass, $resolvedType);
+    }
+
+    /**
+     * @param string $fqsen
+     *
+     * @covers ::resolve
+     * @covers ::<private>
+     *
+     * @uses         phpDocumentor\Reflection\DocBlock\Context
+     * @uses         phpDocumentor\Reflection\Fqsen
+     *
+     * @dataProvider provideFqsen
+     */
+    public function testResolvingFQSENs($fqsen)
+    {
+        $fixture = new Resolver();
+
+        $resolvedType = $fixture->resolve($fqsen, new Context(''));
+
+        $this->assertInstanceOf('phpDocumentor\Reflection\Fqsen', $resolvedType);
+        $this->assertSame($fqsen, (string)$resolvedType);
+    }
+
+
+    /**
+     * @covers ::resolve
+     * @covers ::<private>
+     *
+     * @uses phpDocumentor\Reflection\DocBlock\Context
+     * @uses phpDocumentor\Reflection\Fqsen
+     */
+    public function testResolvingRelativeQSENsBasedOnNamespace()
+    {
+        $fixture = new Resolver();
+
+        $resolvedType = $fixture->resolve('DocBlock', new Context('phpDocumentor\Reflection'));
+
+        $this->assertInstanceOf('phpDocumentor\Reflection\Fqsen', $resolvedType);
+        $this->assertSame('\phpDocumentor\Reflection\DocBlock', (string)$resolvedType);
+    }
+
+    /**
+     * @covers ::resolve
+     * @covers ::<private>
+     *
+     * @uses phpDocumentor\Reflection\DocBlock\Context
+     * @uses phpDocumentor\Reflection\Fqsen
+     */
+    public function testResolvingRelativeQSENsBasedOnNamespaceAlias()
+    {
+        $fixture = new Resolver();
+
+        $resolvedType = $fixture->resolve(
+            'm\MockInterface',
+            new Context('phpDocumentor\Reflection', ['m' => '\Mockery'])
+        );
+
+        $this->assertInstanceOf('phpDocumentor\Reflection\Fqsen', $resolvedType);
+        $this->assertSame('\Mockery\MockInterface', (string)$resolvedType);
+    }
+
+    /**
+     * @covers ::resolve
+     * @covers ::<private>
+     *
+     * @uses phpDocumentor\Reflection\DocBlock\Context
+     * @uses phpDocumentor\Reflection\Types\Array_
+     * @uses phpDocumentor\Reflection\Types\String
+     */
+    public function testResolvingTypedArrays()
+    {
+        $fixture = new Resolver();
+
+        /** @var Array_ $resolvedType */
+        $resolvedType = $fixture->resolve('string[]', new Context(''));
+
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\Array_', $resolvedType);
+        $this->assertSame('string[]', (string)$resolvedType);
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\Mixed', $resolvedType->getKeyType());
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\String', $resolvedType->getValueType());
+    }
+
+    /**
+     * @covers ::resolve
+     * @covers ::<private>
+     *
+     * @uses phpDocumentor\Reflection\DocBlock\Context
+     * @uses phpDocumentor\Reflection\Types\Array_
+     * @uses phpDocumentor\Reflection\Types\String
+     */
+    public function testResolvingNestedTypedArrays()
+    {
+        $fixture = new Resolver();
+
+        /** @var Array_ $resolvedType */
+        $resolvedType = $fixture->resolve('string[][]', new Context(''));
+
+        /** @var Array_ $childValueType */
+        $childValueType = $resolvedType->getValueType();
+
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\Array_', $resolvedType);
+
+        $this->assertSame('string[][]', (string)$resolvedType);
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\Mixed', $resolvedType->getKeyType());
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\Array_', $childValueType);
+
+        $this->assertSame('string[]', (string)$childValueType);
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\Mixed', $childValueType->getKeyType());
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\String', $childValueType->getValueType());
+    }
+
+    /**
+     * @covers ::resolve
+     * @covers ::<private>
+     *
+     * @uses phpDocumentor\Reflection\DocBlock\Context
+     * @uses phpDocumentor\Reflection\Types\Compound
+     * @uses phpDocumentor\Reflection\Types\String
+     * @uses phpDocumentor\Reflection\Fqsen
+     */
+    public function testResolvingCompoundTypes()
+    {
+        $fixture = new Resolver();
+
+        /** @var Compound $resolvedType */
+        $resolvedType = $fixture->resolve('string|Reflection\DocBlock', new Context('phpDocumentor'));
+
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\Compound', $resolvedType);
+        $this->assertSame('string|\phpDocumentor\Reflection\DocBlock', (string)$resolvedType);
+        $this->assertInstanceOf('phpDocumentor\Reflection\Types\String', $resolvedType->get(0));
+        $this->assertInstanceOf('phpDocumentor\Reflection\Fqsen', $resolvedType->get(1));
+    }
+
+    /**
+     * @covers ::resolve
+     * @uses phpDocumentor\Reflection\DocBlock\Context
+     *
+     * @expectedException \InvalidArgumentException
+     */
+    public function testExceptionIsThrownIfTypeIsEmpty()
+    {
+        $fixture = new Resolver();
+        $fixture->resolve(' ', new Context(''));
+    }
+
+    /**
+     * @covers ::resolve
+     * @uses phpDocumentor\Reflection\DocBlock\Context
+     *
+     * @expectedException \InvalidArgumentException
+     */
+    public function testExceptionIsThrownIfTypeIsNotAString()
+    {
+        $fixture = new Resolver();
+        $fixture->resolve(['a'], new Context(''));
+    }
+
+    public function provideKeywords()
+    {
+        return [
+            ['string', 'phpDocumentor\Reflection\Types\String'],
+            ['int', 'phpDocumentor\Reflection\Types\Integer'],
+            ['integer', 'phpDocumentor\Reflection\Types\Integer'],
+            ['float', 'phpDocumentor\Reflection\Types\Float'],
+            ['double', 'phpDocumentor\Reflection\Types\Float'],
+            ['bool', 'phpDocumentor\Reflection\Types\Boolean'],
+            ['boolean', 'phpDocumentor\Reflection\Types\Boolean'],
+            ['resource', 'phpDocumentor\Reflection\Types\Resource'],
+            ['null', 'phpDocumentor\Reflection\Types\Null_'],
+            ['callable', 'phpDocumentor\Reflection\Types\Callable_'],
+            ['callback', 'phpDocumentor\Reflection\Types\Callable_'],
+            ['array', 'phpDocumentor\Reflection\Types\Array_'],
+            ['scalar', 'phpDocumentor\Reflection\Types\Scalar'],
+            ['object', 'phpDocumentor\Reflection\Types\Object_'],
+            ['mixed', 'phpDocumentor\Reflection\Types\Mixed'],
+            ['void', 'phpDocumentor\Reflection\Types\Void'],
+            ['$this', 'phpDocumentor\Reflection\Types\This'],
+            ['static', 'phpDocumentor\Reflection\Types\Static_'],
+            ['self', 'phpDocumentor\Reflection\Types\Self_'],
+        ];
+    }
+
+    public function provideFqsen()
+    {
+        return [
+            'namespace' => ['\phpDocumentor\Reflection'],
+            'class' => ['\phpDocumentor\Reflection\DocBlock'],
+            'function' => ['\DI\object()'],
+            'constant' => ['\phpDocumentor\Reflection\GLOBAL_CONSTANT'],
+            'classConstant' => ['\phpDocumentor\Reflection\DocBlock::CONSTANT'],
+            'property' => ['\phpDocumentor\Reflection\DocBlock::$summary'],
+            'method' => ['\phpDocumentor\Reflection\DocBlock::getSummary()'],
+        ];
+    }
+}