diff --git a/Purtle.php b/Purtle.php
new file mode 100644
index 0000000..ee2262c
--- /dev/null
+++ b/Purtle.php
@@ -0,0 +1,19 @@
+<?php
+
+if ( defined( 'PURTLE_VERSION' ) ) {
+	// Do not initialize more than once.
+	return 1;
+}
+
+define( 'PURTLE_VERSION', '0.1-dev' );
+
+// Include the composer autoloader if it is present.
+if ( is_readable( __DIR__ . '/vendor/autoload.php' ) ) {
+	include_once __DIR__ . '/vendor/autoload.php';
+}
+
+if ( defined( 'MEDIAWIKI' ) ) {
+	call_user_func( function() {
+		require_once __DIR__ . '/init.mw.php';
+	} );
+}
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..247b821
--- /dev/null
+++ b/README.md
@@ -0,0 +1,24 @@
+# Purtle
+
+**Purtle** is a fast, lightweight RDF generator. It provides a "fluent" interface for
+generating RDF output in Turtle, XML/RDF or N-Triples. The fluent interface allows the
+resulting PHP code to be structured just like Turtle notation for RDF, hence the name: "Purtle"
+is a contraction of "PHP Turtle".
+
+The PHP code would look something like this:
+
+    $writer = new TurtleRdfWriter();
+
+    $writer->prefix( 'acme', 'http://acme.test/terms/' );
+
+    $writer->about( 'http://quux.test/Something' )
+      ->a( 'acme', 'Thing' )
+      ->say( 'acme', 'name' )->text( 'Thingy' )->text( 'Dingsda', 'de' )
+      ->say( 'acme', 'owner' )->is( 'http://quux.test/' );
+
+
+## Release notes
+
+### 0.1 (dev)
+
+Initial release.
diff --git a/init.mw.php b/init.mw.php
new file mode 100644
index 0000000..370f6ed
--- /dev/null
+++ b/init.mw.php
@@ -0,0 +1,23 @@
+<?php
+
+if ( !defined( 'MEDIAWIKI' ) ) {
+	die( 'Not an entry point.' );
+}
+
+$GLOBALS['wgExtensionCredits']['wikibase'][] = array(
+	'path' => __FILE__,
+	'name' => 'Purtle',
+	'version' => WIKIBASE_VIEW_VERSION,
+	'author' => array(
+		'Daniel Kinzler',
+		'Stas Malyshev',
+	),
+	'url' => 'https://git.wikimedia.org/blob/mediawiki%2Fextensions%2FWikibase/master/purtle%2FREADME.md',
+	'description' => 'A fast, lightweight RDF generator',
+	'license-name' => 'GPL-2.0+'
+);
+
+
+$GLOBALS['wgHooks']['UnitTestsList'][] = function( array &$paths ) {
+	$paths[] = __DIR__ . '/tests/phpunit';
+};
\ No newline at end of file
diff --git a/src/BNodeLabeler.php b/src/BNodeLabeler.php
new file mode 100644
index 0000000..9ee83bb
--- /dev/null
+++ b/src/BNodeLabeler.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+use InvalidArgumentException;
+
+/**
+ * Helper class for generating labels for blank nodes.
+ *
+ * This serves as a holder for the bnode counter that can be shared between multiple RdfWriter
+ * instances, to avoid conflicting ids.
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+class BNodeLabeler {
+
+	/**
+	 * @var string
+	 */
+	private $prefix;
+
+	/**
+	 * @var int
+	 */
+	private $counter;
+
+	/**
+	 * @param string $prefix
+	 * @param int $start
+	 *
+	 * @throws InvalidArgumentException
+	 */
+	public function __construct( $prefix = 'genid', $start = 1 ) {
+		if ( !is_string( $prefix ) ) {
+			throw new InvalidArgumentException( '$prefix must be a string' );
+		}
+
+		if ( !is_int( $start ) || $start < 1 ) {
+			throw new InvalidArgumentException( '$start must be an int >= 1' );
+		}
+
+		$this->prefix = $prefix;
+		$this->counter = $start;
+	}
+
+	/**
+	 * @param string|null $label node label, will be generated if not given.
+	 *
+	 * @return string
+	 */
+	public function getLabel( $label = null ) {
+		if ( $label === null ) {
+			$label = $this->prefix . $this->counter;
+			$this->counter ++;
+		}
+
+		return $label;
+	}
+
+}
diff --git a/src/N3Quoter.php b/src/N3Quoter.php
new file mode 100644
index 0000000..35f3a76
--- /dev/null
+++ b/src/N3Quoter.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+/**
+ * Helper class for quoting literals and URIs in N3 output.
+ * Optionally supports shorthand and prefix resolution.
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+class N3Quoter {
+
+	/**
+	 * @var UnicodeEscaper
+	 */
+	private $escaper = null;
+
+	/**
+	 * @param bool $escapeUnicode
+	 */
+	public function setEscapeUnicode( $escapeUnicode ) {
+		$this->escaper = $escapeUnicode ? new UnicodeEscaper() : null;
+	}
+
+	public function escapeIRI( $iri ) {
+		//FIXME: apply unicode escaping?!
+		return strtr( $iri, array(
+				' ' => '%20',
+				'"' => '%22',
+				'<' => '%3C',
+				'>' => '%3E',
+		) );
+	}
+
+	public function escapeLiteral( $s ) {
+		$escaped = addcslashes( $s, "\x0..\x1F\"\\" );
+
+		if ( $this->escaper !== null ) {
+			$escaped = $this->escaper->escapeString( $escaped );
+		}
+
+		return $escaped;
+	}
+
+}
diff --git a/src/N3RdfWriterBase.php b/src/N3RdfWriterBase.php
new file mode 100644
index 0000000..575844e
--- /dev/null
+++ b/src/N3RdfWriterBase.php
@@ -0,0 +1,111 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+use InvalidArgumentException;
+
+/**
+ * Base class for RdfWriter implementations that output an N3 dialect.
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+abstract class N3RdfWriterBase extends RdfWriterBase {
+
+	/**
+	 * @var N3Quoter
+	 */
+	protected $quoter;
+
+	/**
+	 * @var bool
+	 */
+	private $trustIRIs = true;
+
+	public function __construct( $role = parent::DOCUMENT_ROLE, BNodeLabeler $labeler = null, N3Quoter $quoter = null ) {
+		parent::__construct( $role, $labeler );
+
+		$this->quoter = $quoter ?: new N3Quoter();
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function getTrustIRIs() {
+		return $this->trustIRIs;
+	}
+
+	/**
+	 * @param bool $trustIRIs
+	 */
+	public function setTrustIRIs( $trustIRIs ) {
+		$this->trustIRIs = $trustIRIs;
+	}
+
+	protected function writeRef( $base, $local = null ) {
+		if ( $local === null ) {
+			if( $base === 'a' ) {
+				$this->write( 'a' );
+			} else {
+				$this->writeIRI( $base );
+			}
+		} else {
+			$this->write( "$base:$local" );
+		}
+	}
+
+	protected function writeShorthand( $shorthand ) {
+// 		if ( $shorthand === null || $shorthand === '' ) {
+// 			throw new InvalidArgumentException( '$shorthand must not be empty' );
+// 		}
+
+		$this->write( $shorthand );
+	}
+
+	protected function writeIRI( $iri ) {
+// 		if ( $iri === null || $iri === '' ) {
+// 			throw new InvalidArgumentException( '$iri must not be empty' );
+// 		}
+
+// 		if ( $iri[0] === '_' || $iri[0] === ':' || $iri[0] === '/' || $iri[0] === '#' ) {
+// 			throw new InvalidArgumentException( '$iri must be an absolute iri: ' . $iri );
+// 		}
+		if ( !$this->trustIRIs ) {
+			$iri = $this->quoter->escapeIRI( $iri );
+		}
+		$this->write( "<$iri>" );
+	}
+
+	protected function writeQName( $base, $local ) {
+// 		if ( $base === null ) {
+// 			throw new InvalidArgumentException( '$base must not be null' );
+// 		}
+
+// 		if ( $local === null || $local === '' ) {
+// 			throw new InvalidArgumentException( '$local must not be empty' );
+// 		}
+
+		$this->write( "$base:$local" );
+	}
+
+
+	protected function writeText( $text, $language = null ) {
+		$value = $this->quoter->escapeLiteral( $text );
+		$this->write( '"' . $value . '"' );
+
+		if ( $language !== null ) {
+			$this->write( '@' . $language );
+		}
+	}
+
+	protected function writeValue( $value, $typeBase = null, $typeLocal = null ) {
+		$value = $this->quoter->escapeLiteral( $value );
+		$this->write( '"' . $value. '"' );
+
+		if ( $typeBase !== null ) {
+			$this->write( '^^' );
+			$this->writeRef( $typeBase, $typeLocal );
+		}
+	}
+
+}
diff --git a/src/NTriplesRdfWriter.php b/src/NTriplesRdfWriter.php
new file mode 100644
index 0000000..df4d385
--- /dev/null
+++ b/src/NTriplesRdfWriter.php
@@ -0,0 +1,103 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+/**
+ * NTriplesRdfWriter
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+class NTriplesRdfWriter extends N3RdfWriterBase {
+
+	public function __construct( $role = parent::DOCUMENT_ROLE, BNodeLabeler $labeler = null, N3Quoter $quoter = null ) {
+		parent::__construct( $role, $labeler, $quoter );
+
+		//NOTE: The RDF 1.1 spec of N-Triples allows full UTF-8, so escaping would not be required.
+		//      However, as of 2015, many consumers of N-Triples still expect non-ASCII characters
+		//      to be escaped.
+		//NOTE: if this is changed, getMimeType must be changed accordingly.
+		$this->quoter->setEscapeUnicode( true );
+
+		$this->transitionTable[self::STATE_OBJECT] = array(
+				self::STATE_DOCUMENT => " .\n",
+				self::STATE_SUBJECT => " .\n",
+				self::STATE_PREDICATE => " .\n",
+				self::STATE_OBJECT => " .\n",
+		);
+	}
+
+	protected function expandSubject( &$base, &$local ) {
+		$this->expandQName( $base, $local );
+	}
+
+	protected function writeSubject( $base, $local = null ) {
+		// noop
+	}
+
+	protected function expandPredicate( &$base, &$local ) {
+		$this->expandShorthand( $base, $local ); // e.g. ( 'a', null ) => ( 'rdf', 'type' )
+		$this->expandQName( $base, $local ); // e.g. ( 'acme', 'foo' ) => ( 'http://amce.test/foo', null )
+	}
+
+	protected function writePredicate( $base, $local = null ) {
+		// noop
+	}
+
+	private function writeSubjectAndObject() {
+		$this->writeRef( $this->currentSubject[0], $this->currentSubject[1] );
+		$this->write( ' ' );
+		$this->writeRef( $this->currentPredicate[0], $this->currentPredicate[1] );
+	}
+
+	protected function expandResource( &$base, &$local ) {
+		$this->expandQName( $base, $local );
+	}
+
+	protected function expandType( &$base, &$local ) {
+		$this->expandQName( $base, $local );
+	}
+
+	protected function writeResource( $base, $local = null ) {
+		$this->writeSubjectAndObject();
+		$this->write( ' ' );
+		$this->writeRef( $base, $local );
+	}
+
+
+	protected function writeText( $text, $language = null ) {
+		$this->writeSubjectAndObject();
+		$this->write( ' ' );
+
+		parent::writeText( $text, $language );
+	}
+
+	protected function writeValue( $value, $typeBase = null, $typeLocal = null ) {
+		$this->writeSubjectAndObject();
+		$this->write( ' ' );
+
+		parent::writeValue( $value, $typeBase, $typeLocal );
+	}
+
+	/**
+	 * @param string $role
+	 * @param BNodeLabeler $labeler
+	 *
+	 * @return RdfWriterBase
+	 */
+	protected function newSubWriter( $role, BNodeLabeler $labeler ) {
+		$writer = new self( $role, $labeler, $this->quoter );
+
+		return $writer;
+	}
+
+	/**
+	 * @return string a MIME type
+	 */
+	public function getMimeType() {
+		//NOTE: Add charset=UTF-8 if and when the constructor configures $this->quoter
+		//      to write utf-8.
+		return 'application/n-triples';
+	}
+
+}
diff --git a/src/RdfWriter.php b/src/RdfWriter.php
new file mode 100644
index 0000000..28ce9a6
--- /dev/null
+++ b/src/RdfWriter.php
@@ -0,0 +1,181 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+/**
+ * Writer interface for RDF output. RdfWriter instances are generally stateful,
+ * but should be implemented to operate in a stream-like manner with a minimum of state.
+ *
+ * This is intended to provide a "fluent interface" that allows programmers to use
+ * a turtle-like structure when generating RDF output. E.g.:
+ *
+ * @code
+ * $writer->prefix( 'acme', 'http://acme.test/terms/' );
+ * $writer->about( 'http://quux.test/Something' )
+ *   ->say( 'acme', 'name' )->text( 'Thingy' )->text( 'Dingsda', 'de' )
+ *   ->say( 'acme', 'owner' )->is( 'http://quux.test/' );
+ * @endcode
+ *
+ * To get the generated RDF output, use the drain() method.
+ *
+ * @note: The contract of this interface follows the GIGO principle, that is,
+ * implementations are not required to ensure valid output or prompt failure on
+ * invalid input. Speed should generally be favored over safety.
+ *
+ * Caveats:
+ * - no relative iris
+ * - predicates must be qnames
+ * - no inline/nested blank nodes
+ * - no comments
+ * - no collections
+ * - no automatic conversion of iris to qnames
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+interface RdfWriter {
+
+	//TODO: split: generic RdfWriter class with shorthands, use RdfFormatters for output
+
+	/**
+	 * Returns the local name of a blank node, for use with the "_" prefix.
+	 *
+	 * @param string|null $label node label, will be generated if not given.
+	 *
+	 * @return string A local name for the blank node, for use with the '_' prefix.
+	 */
+	public function blank( $label = null );
+
+	/**
+	 * Start the document. May generate a header.
+	 */
+	public function start();
+
+	/**
+	 * Finish the document. May generate a footer.
+	 */
+	public function finish();
+
+	/**
+	 * Generates an RDF string from the current buffers state and returns it.
+	 * The buffer is reset to the empty state.
+	 * Before the result string is generated, implementations should close any
+	 * pending syntactical structures (close tags, generate footers, etc).
+	 *
+	 * @return string The RDF output
+	 */
+	public function drain();
+
+	/**
+	 * Declare a prefix for later use. Prefixes should be declared before being used.
+	 * Should not be called after start().
+	 *
+	 * @param string $prefix
+	 * @param string $iri a IRI
+	 */
+	public function prefix( $prefix, $iri );
+
+	/**
+	 * Start an "about" (subject) clause, given a subject.
+	 * Can occur at the beginning odf the output sequence, but can later only follow
+	 * a call to is(), text(), or value().
+	 * Should fail if called at an inappropriate time in the output sequence.
+	 *
+	 * @param string $base A QName prefix if $local is given, or an IRI if $local is null.
+	 * @param string|null $local A QName suffix, or null if $base is an IRI.
+	 *
+	 * @return RdfWriter $this
+	 */
+	public function about( $base, $local = null );
+
+	/**
+	 * Start a predicate clause.
+	 * Can only follow a call to about() or say().
+	 * Should fail if called at an inappropriate time in the output sequence.
+	 *
+	 * @note Unlike about() and is(), say() cannot be called with a full IRI,
+	 * but must always use qname form. This is required to cater to output
+	 * formats that do not allow IRIs to be used as predicates directly,
+	 * like RDF/XML.
+	 *
+	 * @param string $base A QName prefix if $local is given, or a shorthand. MUST NOT be an IRI.
+	 * @param string|null $local A QName suffix, or null if $base is a shorthand.
+	 *
+	 * @return RdfWriter $this
+	 */
+	public function say( $base, $local = null );
+
+	/**
+	 * Produce a resource as the object of a statement.
+	 * Can only follow a call to say() or a call to one of is(), text(), or value().
+	 * Should fail if called at an inappropriate time in the output sequence.
+	 *
+	 * @param string $base A QName prefix if $local is given, or an IRI or shorthand if $local is null.
+	 * @param string|null $local A QName suffix, or null if $base is an IRI or shorthand.
+	 *
+	 * @return RdfWriter $this
+	 */
+	public function is( $base, $local = null );
+
+	/**
+	 * Produce a text literal as the object of a statement.
+	 * Can only follow a call to say() or a call to one of is(), text(), or value().
+	 * Should fail if called at an inappropriate time in the output sequence.
+	 *
+	 * @param string $text the text to be placed in the output
+	 * @param string|null $language the language the text is in
+	 *
+	 * @return RdfWriter $this
+	 */
+	public function text( $text, $language = null );
+
+
+	/**
+	 * Produce a typed or untyped literal as the object of a statement.
+	 * Can only follow a call to say() or a call to one of is(), text(), or value().
+	 * Should fail if called at an inappropriate time in the output sequence.
+	 *
+	 * @param string $value the value encoded as a string
+	 * @param string $typeBase The data type's QName prefix if $typeLocal is given,
+	 *        or an IRI or shorthand if $typeLocal is null.
+	 * @param string|null $typeLocal The data type's  QName suffix,
+	 *        or null if $typeBase is an IRI or shorthand.
+	 *
+	 * @return RdfWriter $this
+	 */
+	public function value( $value, $typeBase = null, $typeLocal = null );
+
+	/**
+	 * Shorthand for say( 'a' )->is( $type ).
+	 *
+	 * @param string $typeBase The data type's QName prefix if $typeLocal is given,
+	 *        or an IRI or shorthand if $typeLocal is null.
+	 * @param string|null $typeLocal The data type's  QName suffix,
+	 *        or null if $typeBase is an IRI or shorthand.
+	 *
+	 * @return RdfWriter $this
+	 */
+	public function a( $typeBase, $typeLocal = null );
+
+	/**
+	 * Returns a document-level sub-writer.
+	 * This can be used to generate parts statements out of sequence.
+	 *
+	 * @note: do not call drain() on sub-writers!
+	 *
+	 * @return RdfWriter
+	 */
+	public function sub();
+
+	/**
+	 * Resets any state the writer may be holding.
+	 */
+	public function reset();
+
+	/**
+	 * Returns the MIME type of the RDF serialization the writer produces.
+	 *
+	 * @return string a MIME type
+	 */
+	public function getMimeType();
+}
diff --git a/src/RdfWriterBase.php b/src/RdfWriterBase.php
new file mode 100644
index 0000000..347a46a
--- /dev/null
+++ b/src/RdfWriterBase.php
@@ -0,0 +1,621 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+use Closure;
+use InvalidArgumentException;
+use LogicException;
+
+/**
+ * Base class for RdfWriter implementations.
+ *
+ * Subclasses have to implement at least the writeXXX() methods to generate the desired output
+ * for the respective RDF constructs. Subclasses may override the startXXX() and finishXXX()
+ * methods to generate structural output, and override expandXXX() to transform identifiers.
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+abstract class RdfWriterBase implements RdfWriter {
+
+	/**
+	 * @var array An array of strings or RdfWriters.
+	 */
+	private $buffer = array();
+
+	const STATE_START = 0;
+	const STATE_DOCUMENT = 5;
+	const STATE_SUBJECT = 10;
+	const STATE_PREDICATE = 11;
+	const STATE_OBJECT = 12;
+	const STATE_FINISH = 666;
+
+	/**
+	 * @var string the current state
+	 */
+	private $state = self::STATE_START;
+
+	/**
+	 * Shorthands that can be used in place of IRIs, e.g. ("a" to mean rdf:type).
+	 *
+	 * @var string[] a map of shorthand names to array( $base, $local ) pairs.
+	 * @todo handle "a" as a special case directly. Use for custom "variables" like %currentValue instead.
+	 */
+	private $shorthands = array();
+
+	/**
+	 * @var string[] a map of prefixes to base IRIs
+	 */
+	private $prefixes = array();
+
+	/**
+	 * @var array pair to store the current subject.
+	 * Holds the $base and $local parameters passed to about().
+	 */
+	protected $currentSubject = array( null, null );
+
+	/**
+	 * @var array pair to store the current predicate.
+	 * Holds the $base and $local parameters passed to say().
+	 */
+	protected $currentPredicate = array( null, null );
+
+	/**
+	 * @var BNodeLabeler
+	 */
+	private $labeler;
+
+	/**
+	 * Role ID for writers that will generate a full RDF document.
+	 */
+	const DOCUMENT_ROLE = 'document';
+	const SUBDOCUMENT_ROLE = 'sub';
+
+	/**
+	 * Role ID for writers that will generate a single inline blank node.
+	 */
+	const BNODE_ROLE = 'bnode';
+
+	/**
+	 * Role ID for writers that will generate a single inline RDR statement.
+	 */
+	const STATEMENT_ROLE = 'statement';
+
+	/**
+	 * @var string The writer's role, see the XXX_ROLE constants.
+	 */
+	protected $role;
+
+	/**
+	 * Are prefixed locked against modification?
+	 * @var bool
+	 */
+	private $prefixesLocked = false;
+
+	/**
+	 * @param string $role The writer's role, use the XXX_ROLE constants.
+	 * @param BNodeLabeler $labeler
+	 *
+	 * @throws InvalidArgumentException
+	 */
+	function __construct( $role, BNodeLabeler $labeler = null ) {
+		if ( !is_string( $role ) ) {
+			throw new InvalidArgumentException( '$role must be a string' );
+		}
+
+		$this->role = $role;
+
+		$this->labeler = $labeler?: new BNodeLabeler();
+
+		$this->registerShorthand( 'a', 'rdf', 'type' );
+
+		$this->prefix( 'rdf', 'http://www.w3.org/1999/02/22-rdf-syntax-ns#' );
+		$this->prefix( 'xsd', 'http://www.w3.org/2001/XMLSchema#' );
+	}
+
+	/**
+	 * @param string $role
+	 * @param BNodeLabeler $labeler
+	 *
+	 * @return RdfWriterBase
+	 */
+	abstract protected function newSubWriter( $role, BNodeLabeler $labeler );
+
+	/**
+	 * Registers a shorthand that can be used instead of a qname,
+	 * like 'a' can be used instead of 'rdf:type'.
+	 *
+	 * @param string $shorthand
+	 * @param string $prefix
+	 * @param string $local
+	 */
+	protected function registerShorthand( $shorthand, $prefix, $local ) {
+		$this->shorthands[$shorthand] = array( $prefix, $local );
+	}
+
+	/**
+	 * Registers a prefix
+	 *
+	 * @param string $prefix
+	 * @param string $iri The base IRI
+	 */
+	public function prefix( $prefix, $iri ) {
+		if( $this->prefixesLocked ) {
+			throw new \LogicException("Prefixes can not be added after start()");
+		}
+		$this->prefixes[$prefix] = $iri;
+	}
+
+	/**
+	 * Determines whether $shorthand can be used as a shorthand.
+	 *
+	 * @param string $shorthand
+	 *
+	 * @return bool
+	 */
+	protected function isShorthand( $shorthand ) {
+		return isset( $this->shorthands[$shorthand] );
+	}
+
+	/**
+	 * Determines whether $shorthand can legally be used as a prefix.
+	 *
+	 * @param string $prefix
+	 *
+	 * @return bool
+	 */
+	protected function isPrefix( $prefix ) {
+		return isset( $this->prefixes[$prefix] );
+	}
+
+	/**
+	 * Returns the prefix map.
+	 *
+	 * @return string[] An associative array mapping prefixes to base IRIs.
+	 */
+	public function getPrefixes() {
+		return $this->prefixes;
+	}
+
+	/**
+	 * @return RdfWriter
+	 */
+	final public function sub() {
+		//FIXME: don't mess with the state, enqueue the writer to be placed in the buffer
+		// later, on the next transtion to subject|document|drain
+		$writer = $this->newSubWriter( self::SUBDOCUMENT_ROLE, $this->labeler );
+		$writer->state = self::STATE_DOCUMENT;
+
+		// share registered prefixes
+		$writer->prefixes =& $this->prefixes;
+
+		$this->write( $writer );
+		return $writer;
+	}
+
+	/**
+	 * Returns the writers role. The role determines the behavior of the writer with respect
+	 * to which states and transitions are possible: a BNODE_ROLE writer would for instance
+	 * not accept a call to about(), since it can only process triples about a single subject
+	 * (the blank node it represents).
+	 *
+	 * @return string A string corresponding to one of the the XXX_ROLE constants.
+	 */
+	final public function getRole() {
+		return $this->role;
+	}
+
+	/**
+	 * Appends string to the output buffer.
+	 * @param string $w
+	 */
+	final protected function write( $w ) {
+		$this->buffer[] = $w;
+	}
+
+	/**
+	 * If $base is a shorthand, $base and $local are updated to hold whatever qname
+	 * the shorthand was associated with.
+	 *
+	 * Otherwise, $base and $local remain unchanged.
+	 *
+	 * @param string &$base
+	 * @param string|null &$local
+	 */
+	protected function expandShorthand( &$base, &$local ) {
+		if ( $local === null && isset( $this->shorthands[$base] ) ) {
+			list( $base, $local ) = $this->shorthands[$base];
+		}
+	}
+
+	/**
+	 * If $base is a registered prefix, $base will be replaced by the base IRI associated with
+	 * that prefix, with $local appended. $local will be set to null.
+	 *
+	 * Otherwise, $base and $local remain unchanged.
+	 *
+	 * @param string &$base
+	 * @param string|null &$local
+	 *
+	 * @throws LogicException
+	 */
+	protected function expandQName( &$base, &$local ) {
+		if ( $local !== null && $base !== '_' ) {
+			if ( isset( $this->prefixes[$base] ) ) {
+				$base = $this->prefixes[$base] . $local; //XXX: can we avoid this concat?
+				$local = null;
+			} else {
+				throw new LogicException( 'Unknown prefix: ' . $base );
+			}
+		}
+	}
+
+	/**
+	 * @see RdfWriter::blank()
+	 *
+	 * @param string|null $label node label, will be generated if not given.
+	 *
+	 * @return string
+	 */
+	final public function blank( $label = null ) {
+		return $this->labeler->getLabel( $label );
+	}
+
+	/**
+	 * @see RdfWriter::start()
+	 */
+	final public function start() {
+		$this->state( self::STATE_DOCUMENT );
+		$this->prefixesLocked = true;
+	}
+
+	/**
+	 * @see RdfWriter::finish()
+	 */
+	final public function finish() {
+		// close all unclosed states
+		$this->state( self::STATE_DOCUMENT );
+		// and then finalize
+		$this->state( self::STATE_FINISH );
+	}
+
+	/**
+	 * @see RdfWriter::drain()
+	 *
+	 * @return string RDF
+	 */
+	final public function drain() {
+		// we can drain after finish, but finish state is sticky
+		if( $this->state != self::STATE_FINISH ) {
+			$this->state( self::STATE_DOCUMENT );
+		}
+		$this->flattenBuffer();
+
+		$rdf = join( '', $this->buffer );
+		$this->buffer = array();
+
+		return $rdf;
+	}
+
+	/**
+	 * @see RdfWriter::reset()
+	 *
+	 * @note Does not reset the blank node counter, because it may be shared.
+	 */
+	public function reset() {
+		$this->buffer = array();
+		$this->state = self::STATE_DOCUMENT; //TODO: may depend on role
+
+		$this->currentSubject = array( null, null );
+		$this->currentPredicate = array( null, null );
+
+// 		$this->prefixes = array();
+// 		$this->prefix( 'rdf', 'http://www.w3.org/1999/02/22-rdf-syntax-ns#' );
+// 		$this->prefix( 'xsd', 'http://www.w3.org/2001/XMLSchema#' );
+	}
+
+	/**
+	 * Calls drain() an any RdfWriter instances in $this->buffer, and replaces them
+	 * in $this->buffer with the string returned by the drain() call. Any closures
+	 * present in the $this->buffer will be called, and replaced by their return value.
+	 */
+	private function flattenBuffer() {
+		foreach ( $this->buffer as &$b ) {
+			if ( $b instanceof Closure ) {
+				$b = $b();
+			}
+			if ( $b instanceof RdfWriter ) {
+				$b = $b->drain();
+			}
+		}
+	}
+
+	/**
+	 * @see RdfWriter::about()
+	 *
+	 * @param string $base A QName prefix if $local is given, or an IRI if $local is null.
+	 * @param string|null $local A QName suffix, or null if $base is an IRI.
+	 *
+	 * @return RdfWriter $this
+	 */
+	final public function about( $base, $local = null ) {
+		$this->expandSubject( $base, $local );
+
+		if ( $base === $this->currentSubject[0] && $local === $this->currentSubject[1] ) {
+			return $this; // redundant about() call
+		}
+
+		$this->state( self::STATE_SUBJECT );
+
+		$this->currentSubject[0] = $base;
+		$this->currentSubject[1] = $local;
+		$this->currentPredicate[0] = null;
+		$this->currentPredicate[1] = null;
+
+		$this->writeSubject( $base, $local );
+		return $this;
+	}
+
+	/**
+	 * @see RdfWriter::a()
+	 * Shorthand for say( 'a' )->is( $type ).
+	 *
+	 * @param string $typeBase The data type's QName prefix if $typeLocal is given,
+	 *        or an IRI or shorthand if $typeLocal is null.
+	 * @param string|null $typeLocal The data type's  QName suffix,
+	 *        or null if $typeBase is an IRI or shorthand.
+	 *
+	 * @return RdfWriter $this
+	 */
+	final public function a( $typeBase, $typeLocal = null ) {
+		return $this->say( 'a' )->is( $typeBase, $typeLocal );
+	}
+
+	/**
+	 * @see RdfWriter::say()
+	 *
+	 * @param string $base A QName prefix.
+	 * @param string $local A QName suffix.
+	 *
+	 * @return RdfWriter $this
+	 */
+	final public function say( $base, $local = null ) {
+		$this->expandPredicate( $base, $local );
+
+		if ( $base === $this->currentPredicate[0] && $local === $this->currentPredicate[1] ) {
+			return $this; // redundant about() call
+		}
+
+		$this->state( self::STATE_PREDICATE );
+
+		$this->currentPredicate[0] = $base;
+		$this->currentPredicate[1] = $local;
+
+		$this->writePredicate( $base, $local );
+		return $this;
+	}
+
+	/**
+	 * @see RdfWriter::is()
+	 *
+	 * @param string $base A QName prefix if $local is given, or an IRI if $local is null.
+	 * @param string|null $local A QName suffix, or null if $base is an IRI.
+	 *
+	 * @return RdfWriter $this
+	 */
+	final public function is( $base, $local = null ) {
+		$this->state( self::STATE_OBJECT );
+
+		$this->expandResource( $base, $local );
+		$this->writeResource( $base, $local );
+		return $this;
+	}
+
+	/**
+	 * @see RdfWriter::text()
+	 *
+	 * @param string $text the text to be placed in the output
+	 * @param string|null $language the language the text is in
+	 *
+	 * @return $this
+	 */
+	final public function text( $text, $language = null ) {
+		$this->state( self::STATE_OBJECT );
+
+		$this->writeText( $text, $language );
+		return $this;
+	}
+
+	/**
+	 * @see RdfWriter::value()
+	 *
+	 * @param string $value the value encoded as a string
+	 * @param string $typeBase The data type's QName prefix if $typeLocal is given,
+	 *        or an IRI or shorthand if $typeLocal is null.
+	 * @param string|null $typeLocal The data type's  QName suffix,
+	 *        or null if $typeBase is an IRI or shorthand.
+	 *
+	 * @return $this
+	 */
+	final public function value( $value, $typeBase = null, $typeLocal = null ) {
+		$this->state( self::STATE_OBJECT );
+
+		if ( $typeBase === null && !is_string( $value ) ) {
+			$vtype = gettype( $value );
+			switch ( $vtype ) {
+				case 'integer':
+					$typeBase = 'xsd';
+					$typeLocal = 'integer';
+					$value = "$value";
+					break;
+
+				case 'double':
+					$typeBase = 'xsd';
+					$typeLocal = 'double';
+					$value = "$value";
+					break;
+
+				case 'boolean':
+					$typeBase = 'xsd';
+					$typeLocal = 'boolean';
+					$value = $value ? 'true' : 'false';
+					break;
+			}
+		}
+
+		$this->expandType( $typeBase, $typeLocal );
+
+		$this->writeValue( $value, $typeBase, $typeLocal );
+		return $this;
+	}
+
+	/**
+	 * State transition table
+	 * First state is "from", second is "to"
+	 * @var array
+	 */
+	protected $transitionTable = array(
+			self::STATE_START => array(
+					self::STATE_DOCUMENT => true,
+			),
+			self::STATE_DOCUMENT => array(
+					self::STATE_DOCUMENT => true,
+					self::STATE_SUBJECT => true,
+					self::STATE_FINISH => true,
+			),
+			self::STATE_SUBJECT => array(
+					self::STATE_PREDICATE => true,
+			),
+			self::STATE_PREDICATE => array(
+					self::STATE_OBJECT => true,
+			),
+			self::STATE_OBJECT => array(
+					self::STATE_DOCUMENT => true,
+					self::STATE_SUBJECT => true,
+					self::STATE_PREDICATE => true,
+					self::STATE_OBJECT => true,
+			),
+	);
+
+	/**
+	 * Perform a state transition. Writer states roughly correspond to states in a naive
+	 * regular parser for the respective syntax. State transitions may generate output,
+	 * particularly of structural elements which correspond to terminals in a respective
+	 * parser.
+	 *
+	 * @param $newState
+	 *
+	 * @throws InvalidArgumentException
+	 */
+	final protected function state( $newState ) {
+		if( !isset( $this->transitionTable[$this->state][$newState] ) ) {
+ 			throw new LogicException( 'Bad transition: ' . $this->state. ' -> ' . $newState  );
+ 		}
+ 		$action = $this->transitionTable[$this->state][$newState];
+ 		if( $action !== true ) {
+ 			if( is_string( $action ) ) {
+ 				$this->write( $action );
+ 			} else {
+ 				$action();
+ 			}
+ 		}
+
+		$this->state = $newState;
+	}
+
+	/**
+	 * Must be implemented to generate output that starts a statement (or set of statements)
+	 * about a subject. Depending on the requirements of the output format, the implementation
+	 * may be empty.
+	 *
+	 * @note: $base and $local are given as passed to about() and processed by expandSubject().
+	 *
+	 * @param string $base
+	 * @param string|null
+	 */
+	protected abstract function writeSubject( $base, $local = null );
+
+	/**
+	 * Must be implemented to generate output that represents the association of a predicate
+	 * with a subject that was previously defined by a call to writeSubject().
+	 *
+	 * @note: $base and $local are given as passed to say() and processed by expandPredicate().
+	 *
+	 * @param string $base
+	 * @param string|null
+	 */
+	protected abstract function writePredicate( $base, $local = null );
+
+	/**
+	 * Must be implemented to generate output that represents a resource used as the object
+	 * of a statement.
+	 *
+	 * @note: $base and $local are given as passed to is() and processed by expandObject().
+	 *
+	 * @param string $base
+	 * @param string|null
+	 */
+	protected abstract function writeResource( $base, $local = null );
+
+	/**
+	 * Must be implemented to generate output that represents a text used as the object
+	 * of a statement.
+	 *
+	 * @param string $text the text to be placed in the output
+	 * @param string|null $language the language the text is in
+	 */
+	protected abstract function writeText( $text, $language );
+
+	/**
+	 * Must be implemented to generate output that represents a (typed) literal used as the object
+	 * of a statement.
+	 *
+	 * @note: $typeBase and $typeLocal are given as passed to value() and processed by expandType().
+	 *
+	 * @param string $value the value encoded as a string
+	 * @param string $typeBase
+	 * @param string|null $typeLocal
+	 */
+	protected abstract function writeValue( $value, $typeBase, $typeLocal = null );
+
+	/**
+	 * Perform any expansion (shorthand to qname, qname to IRI) desired
+	 * for subject identifiers.
+	 *
+	 * @param string &$base
+	 * @param string|null &$local
+	 */
+	protected function expandSubject( &$base, &$local ) {
+	}
+
+	/**
+	 * Perform any expansion (shorthand to qname, qname to IRI) desired
+	 * for predicate identifiers.
+	 *
+	 * @param string &$base
+	 * @param string|null &$local
+	 */
+	protected function expandPredicate( &$base, &$local ) {
+	}
+
+	/**
+	 * Perform any expansion (shorthand to qname, qname to IRI) desired
+	 * for resource identifiers.
+	 *
+	 * @param string &$base
+	 * @param string|null &$local
+	 */
+	protected function expandResource( &$base, &$local ) {
+	}
+
+	/**
+	 * Perform any expansion (shorthand to qname, qname to IRI) desired
+	 * for type identifiers.
+	 *
+	 * @param string &$base
+	 * @param string|null &$local
+	 */
+	protected function expandType( &$base, &$local ) {
+	}
+
+}
diff --git a/src/RdfWriterFactory.php b/src/RdfWriterFactory.php
new file mode 100644
index 0000000..46a04f0
--- /dev/null
+++ b/src/RdfWriterFactory.php
@@ -0,0 +1,159 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+use InvalidArgumentException;
+
+/**
+ * Factory for RdfWriters
+ *
+ * @since 0.5
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class RdfWriterFactory {
+
+	/**
+	 * Returns a list of canonical format names.
+	 * These names for internal use with getMimeTypes() and getFileExtension(),
+	 * they are not themselves MIME types or file extensions.
+	 *
+	 * @return string[]
+	 */
+	public function getSupportedFormats() {
+		return array( 'n3', 'turtle', 'ntriples', 'rdfxml' );
+	}
+
+	/**
+	 * Returns a list of mime types that correspond to the format.
+	 *
+	 * @param string $format a format name, as returned by getSupportedFormats() or getFormatName().
+	 *
+	 * @throws InvalidArgumentException if $format is not a cononical format name
+	 * @return string[]
+	 */
+	public function getMimeTypes( $format ) {
+		//NOTE: Maintaining mime types and file extensions in the RdfWriter implementations
+		//      is tempting, but means we have to load all these classes to find the right
+		//      one for a requested name. Better avoid that overhead when serving lots of
+		//      HTTP requests.
+
+		switch ( strtolower( $format ) ) {
+			case 'n3':
+				return array( 'text/n3', 'text/rdf+n3' );
+
+			case 'turtle':
+				return array( 'text/turtle', 'application/x-turtle' );
+
+			case 'ntriples':
+				return array( 'application/n-triples', 'text/n-triples', 'text/plain' );
+
+			case 'rdfxml':
+				return array( 'application/rdf+xml', 'application/xml', 'text/xml' );
+
+			default:
+				throw new InvalidArgumentException( 'Bad format: ' . $format );
+		}
+	}
+
+	/**
+	 * Returns a file extension that correspond to the format.
+	 *
+	 * @param string $format a format name, as returned by getSupportedFormats() or getFormatName().
+	 *
+	 * @throws InvalidArgumentException if $format is not a cononical format name
+	 * @return string
+	 */
+	public function getFileExtension( $format ) {
+		switch ( strtolower( $format ) ) {
+			case 'n3':
+				return 'n3';
+
+			case 'turtle':
+				return 'ttl';
+
+			case 'ntriples':
+				return 'nt';
+
+			case 'rdfxml':
+				return 'rdf';
+
+			default:
+				throw new InvalidArgumentException( 'Bad format: ' . $format );
+		}
+	}
+
+	/**
+	 * Returns an RdfWriter for the given format name.
+	 *
+	 * @param string $format a format name, as returned by getSupportedFormats() or getFormatName().
+	 *
+	 * @throws InvalidArgumentException if $format is not a cononical format name
+	 * @return RdfWriter the format object, or null if not found.
+	 */
+	public function getWriter( $format ) {
+		switch ( strtolower( $format ) ) {
+			case 'n3':
+				// falls through to turtle
+
+			case 'turtle':
+				return new TurtleRdfWriter();
+
+			case 'ntriples':
+				return new NTriplesRdfWriter();
+
+			case 'rdfxml':
+				return new XmlRdfWriter();
+
+			default:
+				throw new InvalidArgumentException( 'Bad format: ' . $format );
+		}
+	}
+
+	/**
+	 * Returns the canonical format name for $format. $format may be a file extension,
+	 * a mime type, or a common or canonical name of the format.
+	 *
+	 * If no format is found for $format, this method returns false.
+	 *
+	 * @param string $format the name (file extension, mime type) of the desired format.
+	 *
+	 * @return string|false the canonical format name
+	 */
+	public function getFormatName( $format ) {
+		switch ( strtolower( $format ) ) {
+			case 'n3':
+			case 'text/n3':
+			case 'text/rdf+n3':
+				return 'n3';
+
+			case 'ttl':
+			case 'turtle':
+			case 'text/turtle':
+			case 'application/x-turtle':
+				return 'turtle';
+
+			case 'nt':
+			case 'ntriples':
+			case 'n-triples':
+			case 'text/plain':
+			case 'text/n-triples':
+			case 'application/ntriples':
+			case 'application/n-triples':
+				return 'ntriples';
+
+			case 'xml':
+			case 'rdf':
+			case 'rdfxml':
+			case 'application/rdf+xml':
+			case 'application/xml':
+			case 'text/xml':
+				return 'rdfxml';
+
+			default:
+				return false;
+		}
+	}
+
+}
diff --git a/src/TurtleRdfWriter.php b/src/TurtleRdfWriter.php
new file mode 100644
index 0000000..5fbdc45
--- /dev/null
+++ b/src/TurtleRdfWriter.php
@@ -0,0 +1,93 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+/**
+ * RdfWriter implementation for generating Turtle output.
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+class TurtleRdfWriter extends N3RdfWriterBase {
+
+	public function __construct( $role = parent::DOCUMENT_ROLE, BNodeLabeler $labeler = null, N3Quoter $quoter = null ) {
+		parent::__construct( $role, $labeler, $quoter );
+		$this->transitionTable[self::STATE_OBJECT] = array(
+			self::STATE_DOCUMENT => " .\n",
+			self::STATE_SUBJECT => " .\n\n",
+			self::STATE_PREDICATE => " ;\n\t",
+			self::STATE_OBJECT => ",\n\t\t",
+		);
+		$this->transitionTable[self::STATE_DOCUMENT][self::STATE_SUBJECT] = "\n";
+		$this->transitionTable[self::STATE_SUBJECT][self::STATE_PREDICATE] = " ";
+		$this->transitionTable[self::STATE_PREDICATE][self::STATE_OBJECT] = " ";
+		$self = $this;
+		$this->transitionTable[self::STATE_START][self::STATE_DOCUMENT] = function() use($self) {
+			$self->beginDocument();
+		};
+	}
+
+	/**
+	 * Write prefixes
+	 */
+	public function beginDocument( ) {
+		foreach( $this->getPrefixes() as $prefix => $uri ) {
+			$this->write( "@prefix $prefix: <" . $this->quoter->escapeIRI( $uri ) . "> .\n" );
+		}
+	}
+
+	protected function writeSubject( $base, $local = null ) {
+		if( $local !== null ) {
+			$this->write( "$base:$local" );
+		} else {
+			$this->writeIRI( $base );
+		}
+	}
+
+	protected function writePredicate( $base, $local = null ) {
+		if( $base === 'a' ) {
+			$this->write( 'a' );
+			return;
+		}
+		if( $local !== null ) {
+			$this->write( "$base:$local" );
+		} else {
+			$this->writeIRI( $base );
+		}
+	}
+
+	protected function writeResource( $base, $local = null ) {
+		if( $local !== null) {
+			$this->write( "$base:$local" );
+		} else {
+			$this->writeIRI( $base );
+		}
+	}
+
+// 	protected function writeValue( $value, $typeBase = null, $typeLocal = null  ) {
+// 		//TODO: shorthand form for xsd:integer|decimal|double|boolean
+// 		parent::writeValue( $value, $typeBase, $typeLocal );
+// 	}
+
+	/**
+	 * @param string $role
+	 * @param BNodeLabeler $labeler
+	 *
+	 * @return RdfWriterBase
+	 */
+	protected function newSubWriter( $role, BNodeLabeler $labeler ) {
+		$writer = new self( $role, $labeler, $this->quoter );
+
+		return $writer;
+	}
+
+	/**
+	 * @return string a MIME type
+	 */
+	public function getMimeType() {
+		return 'text/turtle; charset=UTF-8';
+	}
+
+
+
+}
diff --git a/src/UnicodeEscaper.php b/src/UnicodeEscaper.php
new file mode 100644
index 0000000..777de3a
--- /dev/null
+++ b/src/UnicodeEscaper.php
@@ -0,0 +1,127 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+/**
+ * Helper class for turning non-ascii characters into Python-style unicode escape sequences.
+ *
+ * @author Daniel Kinzler
+ *
+ * Most of this class was copied from EasyRdf's Ntriples.php.
+ * The following licensing terms apply to the copied code:
+ *
+ * Copyright (c) 2009-2013 Nicholas J Humfrey. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author 'Nicholas J Humfrey" may be used to endorse or
+ *    promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @copyright Copyright (c) 2009-2013 Nicholas J Humfrey
+ * @license http://www.opensource.org/licenses/bsd-license.php
+ */
+class UnicodeEscaper {
+
+	private $escChars = array(); // Character encoding cache
+
+	/**
+	 * @ignore
+	 */
+	public function escapeString( $str ) {
+		$result = '';
+		$strLen = mb_strlen( $str, 'UTF-8' );
+		for ( $i = 0; $i < $strLen; $i++ ) {
+			$c = mb_substr( $str, $i, 1, 'UTF-8' );
+			if ( !isset( $this->escChars[$c] ) ) {
+				$this->escChars[$c] = $this->escapedChar($c);
+			}
+			$result .= $this->escChars[$c];
+		}
+		return $result;
+	}
+
+	/**
+	 * @ignore
+	 */
+	protected function unicodeCharNo( $cUtf ) {
+		$bl = strlen( $cUtf ); /* binary length */
+		$r = 0;
+		switch ( $bl ) {
+			case 1: /* 0####### (0-127) */
+				$r = ord( $cUtf );
+				break;
+			case 2: /* 110##### 10###### = 192+x 128+x */
+				$r = ( ( ord( $cUtf[0] ) - 192 ) * 64 ) +
+					( ord( $cUtf[1] ) - 128 );
+				break;
+			case 3: /* 1110#### 10###### 10###### = 224+x 128+x 128+x */
+				$r = ( ( ord( $cUtf[0] ) - 224 ) * 4096 ) +
+					( ( ord( $cUtf[1] ) - 128 ) * 64 ) +
+					( ord( $cUtf[2] ) - 128 );
+				break;
+			case 4: /* 1111#### 10###### 10###### 10###### = 240+x 128+x 128+x 128+x */
+				$r = ( ( ord( $cUtf[0] ) - 240 ) * 262144 ) +
+					( ( ord( $cUtf[1] ) - 128 ) * 4096 ) +
+					( ( ord( $cUtf[2] ) - 128 ) * 64 ) +
+					( ord( $cUtf[3] ) - 128 );
+				break;
+		}
+		return $r;
+	}
+
+	/**
+	 * @ignore
+	 */
+	protected function escapedChar( $c ) {
+		$no = $this->unicodeCharNo( $c );
+		/* see http://www.w3.org/TR/rdf-testcases/#ntrip_strings */
+		if ( $no < 9 ) {
+			return "\\u" . sprintf( '%04X', $no ); /* #x0-#x8 (0-8) */
+		} elseif ( $no == 9 ) {
+			return '\t'; /* #x9 (9) */
+		} elseif ( $no == 10 ) {
+			return '\n'; /* #xA (10) */
+		} elseif ( $no < 13 ) {
+			return "\\u" . sprintf( '%04X', $no ); /* #xB-#xC (11-12) */
+		} elseif ( $no == 13 ) {
+			return '\r'; /* #xD (13) */
+		} elseif ( $no < 32 ) {
+			return "\\u" . sprintf( '%04X', $no ); /* #xE-#x1F (14-31) */
+		} elseif ( $no < 34 ) {
+			return $c; /* #x20-#x21 (32-33) */
+		} elseif ( $no == 34 ) {
+			return '\"'; /* #x22 (34) */
+		} elseif ( $no < 92 ) {
+			return $c; /* #x23-#x5B (35-91) */
+		} elseif ( $no == 92 ) {
+			return '\\'; /* #x5C (92) */
+		} elseif ( $no < 127 ) {
+			return $c; /* #x5D-#x7E (93-126) */
+		} elseif ( $no < 65536 ) {
+			return "\\u" . sprintf( '%04X', $no ); /* #x7F-#xFFFF (128-65535) */
+		} elseif ( $no < 1114112 ) {
+			return "\\U" . sprintf( '%08X', $no ); /* #x10000-#x10FFFF (65536-1114111) */
+		} else {
+			return ''; /* not defined => ignore */
+		}
+	}
+
+}
diff --git a/src/XmlRdfWriter.php b/src/XmlRdfWriter.php
new file mode 100644
index 0000000..6e4c82b
--- /dev/null
+++ b/src/XmlRdfWriter.php
@@ -0,0 +1,217 @@
+<?php
+
+namespace Wikimedia\Purtle;
+
+use InvalidArgumentException;
+
+/**
+ * XML/RDF implementation of RdfWriter
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+class XmlRdfWriter extends RdfWriterBase {
+
+	public function __construct( $role = parent::DOCUMENT_ROLE, BNodeLabeler $labeler = null ) {
+		parent::__construct( $role, $labeler );
+		// Unfortunately, this is a bit ugly since PHP 5.3 can't call array($this, 'foo') directly
+		// Also due to PHP 5.3 scope issues, used functions need to be public.
+		// TODO: seek better solution (or move to PHP 5.4+)
+		$self = $this;
+		$this->transitionTable[self::STATE_START][self::STATE_DOCUMENT] = function() use($self) {
+			$self->beginDocument();
+		};
+		array($this, 'beginDocument');
+		$this->transitionTable[self::STATE_DOCUMENT][self::STATE_FINISH] = function() use($self) {
+			$self->finishDocument();
+		};
+		$this->transitionTable[self::STATE_OBJECT][self::STATE_DOCUMENT] = function() use($self) {
+			$self->finishSubject();
+		};
+		$this->transitionTable[self::STATE_OBJECT][self::STATE_SUBJECT] = function() use($self) {
+			$self->finishSubject();
+		};
+	}
+
+	private function escape( $text ) {
+		return htmlspecialchars( $text, ENT_QUOTES );
+	}
+
+	protected function expandSubject( &$base, &$local ) {
+		$this->expandQName( $base, $local );
+	}
+
+	protected function expandPredicate( &$base, &$local ) {
+		$this->expandShorthand( $base, $local );
+	}
+
+	protected function expandResource( &$base, &$local ) {
+		$this->expandQName( $base, $local );
+	}
+
+	protected function expandType( &$base, &$local ) {
+		$this->expandQName( $base, $local );
+	}
+
+	private function tag( $ns, $name, $attributes = array(), $content = null ) {
+		$sep = $ns === '' ? '' : ':';
+		$this->write( '<' . $ns . $sep . $name );
+
+		foreach ( $attributes as $attr => $value ) {
+			if ( is_int( $attr ) ) {
+				// positional array entries are passed verbatim, may be callbacks.
+				$this->write( $value );
+				continue;
+			}
+
+			$this->write( " $attr=\"" . $this->escape( $value ) . '"' );
+		}
+
+		if ( $content === null ) {
+			$this->write( '>' );
+		} elseif ( $content === '' ) {
+			$this->write( '/>' );
+		} else {
+			$this->write( '>' . $content );
+			$this->close( $ns, $name );
+		}
+	}
+
+	private function close( $ns, $name ) {
+		$sep = $ns === '' ? '' : ':';
+		$this->write( '</' . $ns . $sep . $name . '>' );
+	}
+
+	/**
+	 * Generates an attribute list, containing the attribute given by $name, or rdf:nodeID
+	 * if $target is a blank node id (starting with "_:"). If $target is a qname, an attempt
+	 * is made to resolve it into a full IRI based on the namespaces registered by calling
+	 * prefix().
+	 *
+	 * @param string $name the attribute name (without the 'rdf:' prefix)
+	 * @param string|null $base
+	 * @param string|null $local
+	 *
+	 * @throws InvalidArgumentException
+	 * @return string[]
+	 */
+	private function getTargetAttributes( $name, $base, $local ) {
+		if ( $base === null && $local === null ) {
+			return array();
+		}
+
+		// handle blank
+		if ( $base === '_' ) {
+			$name = 'nodeID';
+			$value = $local;
+		} elseif ( $local !== null ) {
+			throw new InvalidArgumentException( "Expected IRI, got QName: $base:$local" );
+		} else {
+			$value = $base;
+		}
+
+		return array(
+			"rdf:$name" => $value
+		);
+	}
+
+	/**
+	 * Emit a document header.
+	 */
+	public function beginDocument() {
+		$this->write( "<?xml version=\"1.0\"?>\n" );
+
+		// define a callback for generating namespace attributes
+		$self = $this;
+		$namespaceAttrCallback = function() use ( $self ) {
+			$attr = '';
+
+			$namespaces = $self->getPrefixes();
+			foreach ( $namespaces as $ns => $uri ) {
+				$escapedUri = htmlspecialchars( $uri, ENT_QUOTES );
+				$nss = $ns === '' ? '' : ":$ns";
+				$attr .= " xmlns$nss=\"$escapedUri\"";
+			}
+
+			return $attr;
+		};
+
+		$this->tag( 'rdf', 'RDF', array( $namespaceAttrCallback ) );
+		$this->write( "\n" );
+	}
+
+	protected function writeSubject( $base, $local = null ) {
+		$attr = $this->getTargetAttributes( 'about', $base, $local );
+
+		$this->write( "\t" );
+		$this->tag( 'rdf', 'Description', $attr );
+		$this->write( "\n" );
+	}
+
+	/**
+	 * Emit the root element
+	 */
+	public function finishSubject() {
+		$this->write( "\t" );
+		$this->close( 'rdf', 'Description' );
+		$this->write( "\n" );
+	}
+
+	/**
+	 * Write document footer
+	 */
+	public function finishDocument() {
+		// close document element
+		$this->close( 'rdf', 'RDF' );
+		$this->write( "\n" );
+	}
+
+	protected function writePredicate( $base, $local = null ) {
+		// noop
+	}
+
+	protected function writeResource( $base, $local = null ) {
+		$attr = $this->getTargetAttributes( 'resource', $base, $local );
+
+		$this->write( "\t\t" );
+		$this->tag( $this->currentPredicate[0], $this->currentPredicate[1], $attr, '' );
+		$this->write( "\n" );
+	}
+
+	protected function writeText( $text, $language = null ) {
+		$attr = empty( $language ) ? array() : array( 'xml:lang' => $language );
+
+		$this->write( "\t\t" );
+		$this->tag( $this->currentPredicate[0], $this->currentPredicate[1], $attr, $this->escape( $text ) );
+		$this->write( "\n" );
+	}
+
+	public function writeValue( $literal, $typeBase, $typeLocal = null ) {
+		$attr = $this->getTargetAttributes( 'datatype', $typeBase, $typeLocal );
+
+		$this->write( "\t\t" );
+		$this->tag( $this->currentPredicate[0], $this->currentPredicate[1], $attr, $this->escape( $literal ) );
+		$this->write( "\n" );
+	}
+
+	/**
+	 * @param string $role
+	 * @param BNodeLabeler $labeler
+	 *
+	 * @return RdfWriterBase
+	 */
+	protected function newSubWriter( $role, BNodeLabeler $labeler ) {
+		$writer = new self( $role, $labeler );
+
+		return $writer;
+	}
+
+	/**
+	 * @return string a MIME type
+	 */
+	public function getMimeType() {
+		return 'application/rdf+xml; charset=UTF-8';
+	}
+
+
+}
diff --git a/tests/data/EricMiller.nt b/tests/data/EricMiller.nt
new file mode 100644
index 0000000..6e94cfa
--- /dev/null
+++ b/tests/data/EricMiller.nt
@@ -0,0 +1,4 @@
+<http://www.w3.org/People/EM/contact#me> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2000/10/swap/pim/contact#Person> .
+<http://www.w3.org/People/EM/contact#me> <http://www.w3.org/2000/10/swap/pim/contact#fullName> "Eric Miller" .
+<http://www.w3.org/People/EM/contact#me> <http://www.w3.org/2000/10/swap/pim/contact#mailbox> <mailto:em@w3.org> .
+<http://www.w3.org/People/EM/contact#me> <http://www.w3.org/2000/10/swap/pim/contact#personalTitle> "Dr." .
diff --git a/tests/data/EricMiller.rdf b/tests/data/EricMiller.rdf
new file mode 100644
index 0000000..193e8b9
--- /dev/null
+++ b/tests/data/EricMiller.rdf
@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:contact="http://www.w3.org/2000/10/swap/pim/contact#">
+	<rdf:Description rdf:about="http://www.w3.org/People/EM/contact#me">
+		<rdf:type rdf:resource="http://www.w3.org/2000/10/swap/pim/contact#Person"/>
+		<contact:fullName>Eric Miller</contact:fullName>
+		<contact:mailbox rdf:resource="mailto:em@w3.org"/>
+		<contact:personalTitle>Dr.</contact:personalTitle>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/EricMiller.ttl b/tests/data/EricMiller.ttl
new file mode 100644
index 0000000..e51dba6
--- /dev/null
+++ b/tests/data/EricMiller.ttl
@@ -0,0 +1,8 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix contact: <http://www.w3.org/2000/10/swap/pim/contact#> .
+
+<http://www.w3.org/People/EM/contact#me> rdf:type contact:Person ;
+	contact:fullName "Eric Miller" ;
+	contact:mailbox <mailto:em@w3.org> ;
+	contact:personalTitle "Dr." .
diff --git a/tests/data/LabeledBlankNode.nt b/tests/data/LabeledBlankNode.nt
new file mode 100644
index 0000000..332ae35
--- /dev/null
+++ b/tests/data/LabeledBlankNode.nt
@@ -0,0 +1,5 @@
+<http://www.example.org/staffid/85740> <http://www.example.org/terms/address> _:johnaddress .
+_:johnaddress <http://www.example.org/terms/street> "1501 Grant Avenue" .
+_:johnaddress <http://www.example.org/terms/city> "Bedfort" .
+_:johnaddress <http://www.example.org/terms/state> "Massachusetts" .
+_:johnaddress <http://www.example.org/terms/postalCode> "01730" .
diff --git a/tests/data/LabeledBlankNode.rdf b/tests/data/LabeledBlankNode.rdf
new file mode 100644
index 0000000..61cc8c7
--- /dev/null
+++ b/tests/data/LabeledBlankNode.rdf
@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:exterms="http://www.example.org/terms/" xmlns:exstaff="http://www.example.org/staffid/">
+	<rdf:Description rdf:about="http://www.example.org/staffid/85740">
+		<exterms:address rdf:nodeID="johnaddress"/>
+	</rdf:Description>
+	<rdf:Description rdf:nodeID="johnaddress">
+		<exterms:street>1501 Grant Avenue</exterms:street>
+		<exterms:city>Bedfort</exterms:city>
+		<exterms:state>Massachusetts</exterms:state>
+		<exterms:postalCode>01730</exterms:postalCode>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/LabeledBlankNode.ttl b/tests/data/LabeledBlankNode.ttl
new file mode 100644
index 0000000..8a9ab8e
--- /dev/null
+++ b/tests/data/LabeledBlankNode.ttl
@@ -0,0 +1,11 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix exterms: <http://www.example.org/terms/> .
+@prefix exstaff: <http://www.example.org/staffid/> .
+
+exstaff:85740 exterms:address _:johnaddress .
+
+_:johnaddress exterms:street "1501 Grant Avenue" ;
+	exterms:city "Bedfort" ;
+	exterms:state "Massachusetts" ;
+	exterms:postalCode "01730" .
diff --git a/tests/data/NumberedBlankNode.nt b/tests/data/NumberedBlankNode.nt
new file mode 100644
index 0000000..f179ee1
--- /dev/null
+++ b/tests/data/NumberedBlankNode.nt
@@ -0,0 +1,4 @@
+<http://www.example.org/staffid/Sue> <http://www.example.org/terms/publication> _:genid1 .
+_:genid1 <http://www.example.org/terms/title> "Antology of Time" .
+<http://www.example.org/staffid/Jack> <http://www.example.org/terms/publication> _:genid2 .
+_:genid2 <http://www.example.org/terms/title> "Anthony of Time" .
diff --git a/tests/data/NumberedBlankNode.rdf b/tests/data/NumberedBlankNode.rdf
new file mode 100644
index 0000000..0608a77
--- /dev/null
+++ b/tests/data/NumberedBlankNode.rdf
@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:exterms="http://www.example.org/terms/" xmlns:exstaff="http://www.example.org/staffid/" xmlns:ex="http://example.org/packages/vocab#">
+	<rdf:Description rdf:about="http://www.example.org/staffid/Sue">
+		<exterms:publication rdf:nodeID="genid1"/>
+	</rdf:Description>
+	<rdf:Description rdf:nodeID="genid1">
+		<exterms:title>Antology of Time</exterms:title>
+	</rdf:Description>
+	<rdf:Description rdf:about="http://www.example.org/staffid/Jack">
+		<exterms:publication rdf:nodeID="genid2"/>
+	</rdf:Description>
+	<rdf:Description rdf:nodeID="genid2">
+		<exterms:title>Anthony of Time</exterms:title>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/NumberedBlankNode.ttl b/tests/data/NumberedBlankNode.ttl
new file mode 100644
index 0000000..9659d84
--- /dev/null
+++ b/tests/data/NumberedBlankNode.ttl
@@ -0,0 +1,13 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix exterms: <http://www.example.org/terms/> .
+@prefix exstaff: <http://www.example.org/staffid/> .
+@prefix ex: <http://example.org/packages/vocab#> .
+
+exstaff:Sue exterms:publication _:genid1 .
+
+_:genid1 exterms:title "Antology of Time" .
+
+exstaff:Jack exterms:publication _:genid2 .
+
+_:genid2 exterms:title "Anthony of Time" .
diff --git a/tests/data/Numbers.nt b/tests/data/Numbers.nt
new file mode 100644
index 0000000..31b9c75
--- /dev/null
+++ b/tests/data/Numbers.nt
@@ -0,0 +1,3 @@
+<http://acme.test/Bongos> <http://acme.test/stock> "5"^^<http://www.w3.org/2001/XMLSchema#integer> .
+<http://acme.test/Bongos> <http://acme.test/stock> "7"^^<http://www.w3.org/2001/XMLSchema#integer> .
+<http://acme.test/Tablas> <http://acme.test/stock> "6"^^<http://www.w3.org/2001/XMLSchema#integer> .
diff --git a/tests/data/Numbers.rdf b/tests/data/Numbers.rdf
new file mode 100644
index 0000000..190ff29
--- /dev/null
+++ b/tests/data/Numbers.rdf
@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:acme="http://acme.test/">
+	<rdf:Description rdf:about="http://acme.test/Bongos">
+		<acme:stock rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">5</acme:stock>
+		<acme:stock rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">7</acme:stock>
+	</rdf:Description>
+	<rdf:Description rdf:about="http://acme.test/Tablas">
+		<acme:stock rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">6</acme:stock>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/Numbers.ttl b/tests/data/Numbers.ttl
new file mode 100644
index 0000000..d2b8710
--- /dev/null
+++ b/tests/data/Numbers.ttl
@@ -0,0 +1,8 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix acme: <http://acme.test/> .
+
+acme:Bongos acme:stock "5"^^xsd:integer,
+		"7"^^xsd:integer .
+
+acme:Tablas acme:stock "6"^^xsd:integer .
diff --git a/tests/data/Predicates.nt b/tests/data/Predicates.nt
new file mode 100644
index 0000000..40d76b1
--- /dev/null
+++ b/tests/data/Predicates.nt
@@ -0,0 +1,4 @@
+<http://foobar.test/Bananas> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://foobar.test/Fruit> .
+<http://foobar.test/Bananas> <http://acme.test/name> "Banana" .
+<http://foobar.test/Bananas> <http://acme.test/name> "Banane"@de .
+<http://foobar.test/Apples> <http://acme.test/name> "Apple" .
diff --git a/tests/data/Predicates.rdf b/tests/data/Predicates.rdf
new file mode 100644
index 0000000..b8da7f9
--- /dev/null
+++ b/tests/data/Predicates.rdf
@@ -0,0 +1,11 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns="http://acme.test/">
+	<rdf:Description rdf:about="http://foobar.test/Bananas">
+		<rdf:type rdf:resource="http://foobar.test/Fruit"/>
+		<name>Banana</name>
+		<name xml:lang="de">Banane</name>
+	</rdf:Description>
+	<rdf:Description rdf:about="http://foobar.test/Apples">
+		<name>Apple</name>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/Predicates.ttl b/tests/data/Predicates.ttl
new file mode 100644
index 0000000..bf1a171
--- /dev/null
+++ b/tests/data/Predicates.ttl
@@ -0,0 +1,9 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix : <http://acme.test/> .
+
+<http://foobar.test/Bananas> a <http://foobar.test/Fruit> ;
+	:name "Banana",
+		"Banane"@de .
+
+<http://foobar.test/Apples> :name "Apple" .
diff --git a/tests/data/Resources.nt b/tests/data/Resources.nt
new file mode 100644
index 0000000..525a42e
--- /dev/null
+++ b/tests/data/Resources.nt
@@ -0,0 +1,2 @@
+<http://acme.test/Bongos> <http://acme.test/sounds> <http://acme.test/Bing> .
+<http://acme.test/Bongos> <http://acme.test/sounds> <http://foobar.test/sound/Bang> .
diff --git a/tests/data/Resources.rdf b/tests/data/Resources.rdf
new file mode 100644
index 0000000..f2502d5
--- /dev/null
+++ b/tests/data/Resources.rdf
@@ -0,0 +1,7 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:acme="http://acme.test/">
+	<rdf:Description rdf:about="http://acme.test/Bongos">
+		<acme:sounds rdf:resource="http://acme.test/Bing"/>
+		<acme:sounds rdf:resource="http://foobar.test/sound/Bang"/>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/Resources.ttl b/tests/data/Resources.ttl
new file mode 100644
index 0000000..e9153e4
--- /dev/null
+++ b/tests/data/Resources.ttl
@@ -0,0 +1,6 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix acme: <http://acme.test/> .
+
+acme:Bongos acme:sounds acme:Bing,
+		<http://foobar.test/sound/Bang> .
diff --git a/tests/data/Texts.nt b/tests/data/Texts.nt
new file mode 100644
index 0000000..d927334
--- /dev/null
+++ b/tests/data/Texts.nt
@@ -0,0 +1,2 @@
+<http://acme.test/Bongos> <http://acme.test/sounds> "Bom"@de .
+<http://acme.test/Bongos> <http://acme.test/sounds> "Bam"@en .
diff --git a/tests/data/Texts.rdf b/tests/data/Texts.rdf
new file mode 100644
index 0000000..e6d14ed
--- /dev/null
+++ b/tests/data/Texts.rdf
@@ -0,0 +1,7 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:acme="http://acme.test/">
+	<rdf:Description rdf:about="http://acme.test/Bongos">
+		<acme:sounds xml:lang="de">Bom</acme:sounds>
+		<acme:sounds xml:lang="en">Bam</acme:sounds>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/Texts.ttl b/tests/data/Texts.ttl
new file mode 100644
index 0000000..ccb4c2a
--- /dev/null
+++ b/tests/data/Texts.ttl
@@ -0,0 +1,6 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix acme: <http://acme.test/> .
+
+acme:Bongos acme:sounds "Bom"@de,
+		"Bam"@en .
diff --git a/tests/data/Triples.nt b/tests/data/Triples.nt
new file mode 100644
index 0000000..a185271
--- /dev/null
+++ b/tests/data/Triples.nt
@@ -0,0 +1,3 @@
+<http://foobar.test/Bananas> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://foobar.test/Fruit> .
+<http://acme.test/Nuts> <http://acme.test/weight> "5.5"^^<http://www.w3.org/2001/XMLSchema#decimal> .
+<http://acme.test/Nuts> <http://acme.test/color> "brown" .
diff --git a/tests/data/Triples.rdf b/tests/data/Triples.rdf
new file mode 100644
index 0000000..c61e00d
--- /dev/null
+++ b/tests/data/Triples.rdf
@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:acme="http://acme.test/">
+	<rdf:Description rdf:about="http://foobar.test/Bananas">
+		<rdf:type rdf:resource="http://foobar.test/Fruit"/>
+	</rdf:Description>
+	<rdf:Description rdf:about="http://acme.test/Nuts">
+		<acme:weight rdf:datatype="http://www.w3.org/2001/XMLSchema#decimal">5.5</acme:weight>
+		<acme:color>brown</acme:color>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/Triples.ttl b/tests/data/Triples.ttl
new file mode 100644
index 0000000..b7575bc
--- /dev/null
+++ b/tests/data/Triples.ttl
@@ -0,0 +1,8 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix acme: <http://acme.test/> .
+
+<http://foobar.test/Bananas> a <http://foobar.test/Fruit> .
+
+acme:Nuts acme:weight "5.5"^^xsd:decimal ;
+	acme:color "brown" .
diff --git a/tests/data/Values.nt b/tests/data/Values.nt
new file mode 100644
index 0000000..ff36320
--- /dev/null
+++ b/tests/data/Values.nt
@@ -0,0 +1,19 @@
+<http://foobar.test/Bananas> <http://acme.test/multi> "A" .
+<http://foobar.test/Bananas> <http://acme.test/multi> "B" .
+<http://foobar.test/Bananas> <http://acme.test/multi> "C" .
+<http://foobar.test/Bananas> <http://acme.test/type> "foo"^^<http://acme.test/thing> .
+<http://foobar.test/Bananas> <http://acme.test/type> "-5"^^<http://www.w3.org/2001/XMLSchema#integer> .
+<http://foobar.test/Bananas> <http://acme.test/type> "-5"^^<http://www.w3.org/2001/XMLSchema#decimal> .
+<http://foobar.test/Bananas> <http://acme.test/type> "-5"^^<http://www.w3.org/2001/XMLSchema#double> .
+<http://foobar.test/Bananas> <http://acme.test/type> "true"^^<http://www.w3.org/2001/XMLSchema#boolean> .
+<http://foobar.test/Bananas> <http://acme.test/type> "false"^^<http://www.w3.org/2001/XMLSchema#boolean> .
+<http://foobar.test/Bananas> <http://acme.test/autotype> "-5"^^<http://www.w3.org/2001/XMLSchema#integer> .
+<http://foobar.test/Bananas> <http://acme.test/autotype> "3.14"^^<http://www.w3.org/2001/XMLSchema#double> .
+<http://foobar.test/Bananas> <http://acme.test/autotype> "true"^^<http://www.w3.org/2001/XMLSchema#boolean> .
+<http://foobar.test/Bananas> <http://acme.test/autotype> "false"^^<http://www.w3.org/2001/XMLSchema#boolean> .
+<http://foobar.test/Bananas> <http://acme.test/no-autotype> "-5"^^<http://www.w3.org/2001/XMLSchema#decimal> .
+<http://foobar.test/Bananas> <http://acme.test/no-autotype> "3.14"^^<http://www.w3.org/2001/XMLSchema#string> .
+<http://foobar.test/Bananas> <http://acme.test/no-autotype> "1"^^<http://www.w3.org/2001/XMLSchema#string> .
+<http://foobar.test/Bananas> <http://acme.test/no-autotype> ""^^<http://www.w3.org/2001/XMLSchema#string> .
+<http://foobar.test/Bananas> <http://acme.test/shorthand> "foo" .
+<http://foobar.test/Bananas> <http://acme.test/typed-shorthand> "foo"^^<http://acme.test/thing> .
\ No newline at end of file
diff --git a/tests/data/Values.rdf b/tests/data/Values.rdf
new file mode 100644
index 0000000..4819b75
--- /dev/null
+++ b/tests/data/Values.rdf
@@ -0,0 +1,24 @@
+<?xml version="1.0"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:acme="http://acme.test/">
+	<rdf:Description rdf:about="http://foobar.test/Bananas">
+		<acme:multi>A</acme:multi>
+		<acme:multi>B</acme:multi>
+		<acme:multi>C</acme:multi>
+		<acme:type rdf:datatype="http://acme.test/thing">foo</acme:type>
+		<acme:type rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">-5</acme:type>
+		<acme:type rdf:datatype="http://www.w3.org/2001/XMLSchema#decimal">-5</acme:type>
+		<acme:type rdf:datatype="http://www.w3.org/2001/XMLSchema#double">-5</acme:type>
+		<acme:type rdf:datatype="http://www.w3.org/2001/XMLSchema#boolean">true</acme:type>
+		<acme:type rdf:datatype="http://www.w3.org/2001/XMLSchema#boolean">false</acme:type>
+		<acme:autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">-5</acme:autotype>
+		<acme:autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#double">3.14</acme:autotype>
+		<acme:autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#boolean">true</acme:autotype>
+		<acme:autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#boolean">false</acme:autotype>
+		<acme:no-autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#decimal">-5</acme:no-autotype>
+		<acme:no-autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#string">3.14</acme:no-autotype>
+		<acme:no-autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#string">1</acme:no-autotype>
+		<acme:no-autotype rdf:datatype="http://www.w3.org/2001/XMLSchema#string"/>
+		<acme:shorthand>foo</acme:shorthand>
+		<acme:typed-shorthand rdf:datatype="http://acme.test/thing">foo</acme:typed-shorthand>
+	</rdf:Description>
+</rdf:RDF>
\ No newline at end of file
diff --git a/tests/data/Values.ttl b/tests/data/Values.ttl
new file mode 100644
index 0000000..ba5c0d3
--- /dev/null
+++ b/tests/data/Values.ttl
@@ -0,0 +1,23 @@
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix acme: <http://acme.test/> .
+
+<http://foobar.test/Bananas> acme:multi "A",
+		"B",
+		"C" ;
+	acme:type "foo"^^acme:thing,
+		"-5"^^xsd:integer,
+		"-5"^^xsd:decimal,
+		"-5"^^xsd:double,
+		"true"^^xsd:boolean,
+		"false"^^xsd:boolean ;
+	acme:autotype "-5"^^xsd:integer,
+		"3.14"^^xsd:double,
+		"true"^^xsd:boolean,
+		"false"^^xsd:boolean ;
+	acme:no-autotype "-5"^^xsd:decimal,
+		"3.14"^^xsd:string,
+		"1"^^xsd:string,
+		""^^xsd:string ;
+	acme:shorthand "foo" ;
+	acme:typed-shorthand "foo"^^acme:thing .
diff --git a/tests/phpunit/BNodeLabelerTest.php b/tests/phpunit/BNodeLabelerTest.php
new file mode 100644
index 0000000..a660d4a
--- /dev/null
+++ b/tests/phpunit/BNodeLabelerTest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\BNodeLabeler;
+
+/**
+ * @covers Wikimedia\Purtle\BNodeLabeler
+ *
+ * @group Purtle
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class BNodeLabelerTest extends \PHPUnit_Framework_TestCase {
+
+	public function testGetLabel() {
+		$labeler = new BNodeLabeler( 'test', 2 );
+
+		$this->assertEquals( 'test2', $labeler->getLabel() );
+		$this->assertEquals( 'test3', $labeler->getLabel() );
+		$this->assertEquals( 'foo', $labeler->getLabel( 'foo' ) );
+		$this->assertEquals( 'test4', $labeler->getLabel() );
+	}
+
+}
diff --git a/tests/phpunit/N3QuoterTest.php b/tests/phpunit/N3QuoterTest.php
new file mode 100644
index 0000000..fe239af
--- /dev/null
+++ b/tests/phpunit/N3QuoterTest.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\N3Quoter;
+
+/**
+ * @covers Wikimedia\Purtle\N3Quoter
+ *
+ * @group Purtle
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class N3QuoterTest extends \PHPUnit_Framework_TestCase {
+
+	public function provideEscapeIRI() {
+		return array(
+			array( 'http://acme.com/test.php?x=y&foo=bar#part', 'http://acme.com/test.php?x=y&foo=bar#part' ),
+			array( 'http://acme.com/"evil stuff"', 'http://acme.com/%22evil%20stuff%22' ),
+			array( 'http://acme.com/<wacky stuff>', 'http://acme.com/%3Cwacky%20stuff%3E' ),
+		);
+	}
+
+	/**
+	 * @dataProvider provideEscapeIRI
+	 */
+	public function testEscapeIRI( $iri, $expected ) {
+		$quoter = new N3Quoter();
+
+		$this->assertEquals( $expected, $quoter->escapeIRI( $iri ) );
+	}
+
+	public function provideEscapeLiteral() {
+		return array(
+			array( "Hello World", 'Hello World' ),
+			array( "Hello\nWorld", 'Hello\nWorld' ),
+			array( "Hello\tWorld", 'Hello\tWorld' ),
+			array( "Hällo Wörld", 'Hällo Wörld', false ),
+			array( "Hällo Wörld", 'H\u00E4llo W\u00F6rld', true ),
+		);
+	}
+
+	/**
+	 * @dataProvider provideEscapeLiteral
+	 */
+	public function testEscapeLiteral( $literal, $expected, $escapeUnicode = false ) {
+		$quoter = new N3Quoter();
+		$quoter->setEscapeUnicode( $escapeUnicode );
+
+		$this->assertEquals( $expected, $quoter->escapeLiteral( $literal ) );
+	}
+
+}
diff --git a/tests/phpunit/NTriplesRdfWriterTest.php b/tests/phpunit/NTriplesRdfWriterTest.php
new file mode 100644
index 0000000..b3d5f63
--- /dev/null
+++ b/tests/phpunit/NTriplesRdfWriterTest.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\NTriplesRdfWriter;
+use Wikimedia\Purtle\RdfWriter;
+
+/**
+ * @covers Wikimedia\Purtle\NTriplesRdfWriter
+ *
+ * @group Purtle
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class NTriplesRdfWriterTest extends RdfWriterTestBase {
+
+	protected function getFileSuffix() {
+		return 'nt';
+	}
+
+	/**
+	 * @return RdfWriter
+	 */
+	protected function newWriter() {
+		return new NTriplesRdfWriter();
+	}
+}
diff --git a/tests/phpunit/RdfWriterFactoryTest.php b/tests/phpunit/RdfWriterFactoryTest.php
new file mode 100644
index 0000000..88658a4
--- /dev/null
+++ b/tests/phpunit/RdfWriterFactoryTest.php
@@ -0,0 +1,110 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\RdfWriterFactory;
+
+/**
+ * @covers Wikimedia\Purtle\RdfWriterFactory
+ *
+ * @group Purtle
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class RdfWriterFactoryTest extends \MediaWikiTestCase {
+
+	public function testSupportedFormats() {
+		$factory = new RdfWriterFactory();
+
+		$formats = $factory->getSupportedFormats();
+
+		$this->assertInternalType( 'array', $formats );
+		$this->assertNotEmpty( $formats );
+	}
+
+	public function testGetWriter() {
+		$factory = new RdfWriterFactory();
+
+		foreach ( $factory->getSupportedFormats() as $format ) {
+			$writer = $factory->getWriter( $format );
+
+			$this->assertInstanceOf( 'Wikimedia\Purtle\RdfWriter', $writer );
+		}
+	}
+
+	public function testGetFormatName() {
+		$factory = new RdfWriterFactory();
+
+		foreach ( $factory->getSupportedFormats() as $format ) {
+			$actual = $factory->getFormatName( $format );
+
+			// the canonical name should just stay
+			$this->assertEquals( $format, $actual );
+		}
+	}
+
+	public function provideFormats() {
+		return array(
+			// N3 (currently falls through to turtle)
+			array( 'n3', 'n3', 'n3', 'text/n3' ),
+			array( 'text/n3', 'n3', 'n3', 'text/n3' ),
+			array( 'text/rdf+n3', 'n3', 'n3', 'text/n3' ),
+
+			array( 'ttl', 'turtle', 'ttl', 'text/turtle' ),
+			array( 'turtle', 'turtle', 'ttl', 'text/turtle' ),
+			array( 'text/turtle', 'turtle', 'ttl', 'text/turtle' ),
+			array( 'application/x-turtle', 'turtle', 'ttl', 'text/turtle' ),
+
+			array( 'nt', 'ntriples', 'nt', 'application/n-triples' ),
+			array( 'ntriples', 'ntriples', 'nt', 'application/n-triples' ),
+			array( 'n-triples', 'ntriples', 'nt', 'application/n-triples' ),
+			array( 'text/plain', 'ntriples', 'nt', 'application/n-triples' ),
+			array( 'text/n-triples', 'ntriples', 'nt', 'application/n-triples' ),
+			array( 'application/ntriples', 'ntriples', 'nt', 'application/n-triples' ),
+			array( 'application/n-triples', 'ntriples', 'nt', 'application/n-triples' ),
+
+			array( 'xml', 'rdfxml', 'rdf', 'application/rdf+xml' ),
+			array( 'rdf', 'rdfxml', 'rdf', 'application/rdf+xml' ),
+			array( 'rdfxml', 'rdfxml', 'rdf', 'application/rdf+xml' ),
+			array( 'application/rdf+xml', 'rdfxml', 'rdf', 'application/rdf+xml' ),
+			array( 'application/xml', 'rdfxml', 'rdf', 'application/rdf+xml' ),
+			array( 'text/xml', 'rdfxml', 'rdf', 'application/rdf+xml' ),
+		);
+	}
+
+	/**
+	 * @dataProvider provideFormats
+	 */
+	public function testFormats( $name, $canonicalName, $expectedFileExtension, $expectedMimeType ) {
+		$factory = new RdfWriterFactory();
+
+		$this->assertEquals( $canonicalName, $factory->getFormatName( $name ) );
+		$this->assertEquals( $expectedFileExtension, $factory->getFileExtension( $canonicalName ) );
+		$this->assertContains( $expectedMimeType, $factory->getMimeTypes( $canonicalName ) );
+
+		$writer = $factory->getWriter( $canonicalName );
+		$this->assertInstanceOf( 'Wikimedia\Purtle\RdfWriter', $writer );
+	}
+
+	public function testGetMimeTypes() {
+		$factory = new RdfWriterFactory();
+
+		foreach ( $factory->getSupportedFormats() as $format ) {
+			$mimeTypes = $factory->getMimeTypes( $format );
+
+			$this->assertInternalType( 'array', $mimeTypes );
+			$this->assertNotEmpty( $mimeTypes );
+		}
+	}
+
+	public function testGetFileExtensions() {
+		$factory = new RdfWriterFactory();
+
+		foreach ( $factory->getSupportedFormats() as $format ) {
+			$extension = $factory->getFileExtension( $format );
+
+			$this->assertInternalType( 'string', $extension );
+		}
+	}
+}
diff --git a/tests/phpunit/RdfWriterTestBase.php b/tests/phpunit/RdfWriterTestBase.php
new file mode 100644
index 0000000..a683b1f
--- /dev/null
+++ b/tests/phpunit/RdfWriterTestBase.php
@@ -0,0 +1,259 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\RdfWriter;
+
+/**
+ * Base class for tests for RdfWriter implementations.
+ * Provides a common test suite for all implementations.
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+abstract class RdfWriterTestBase extends \PHPUnit_Framework_TestCase{
+
+	abstract protected function getFileSuffix();
+
+	protected function getExpectedOutputFile( $datasetName ) {
+		$path = __DIR__ . '/../data/' . $datasetName . '.' . $this->getFileSuffix();
+		return $path;
+	}
+
+	private function normalizeLines( array $lines ) {
+		$normalized = array();
+
+		foreach ( $lines as $s ) {
+			$s = trim( $s, "\r\n" );
+			$normalized[] = $s;
+		}
+
+		return $normalized;
+	}
+
+	protected function assertOutputLines( $datasetName, $actual ) {
+		if ( is_string( $actual ) ) {
+			$actual = trim( $actual, "\r\n" );
+			$actual = explode( "\n", $actual );
+		}
+
+		$path = $this->getExpectedOutputFile( $datasetName );
+
+		// Create test data file if it doesn't exist.
+		//if ( !file_exists( $path ) ) {
+		//	file_put_contents( $path . '.actual', join( "\n", $actual ) );
+		//}
+
+		$expected = file( $path );
+
+		$expected = $this->normalizeLines( $expected );
+		$actual = $this->normalizeLines( $actual );
+
+		$this->assertEquals( $expected, $actual, 'Result mismatches data in ' . $path );
+	}
+
+	/**
+	 * @return RdfWriter
+	 */
+	protected abstract function newWriter();
+
+	public function testTriples() {
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'acme', 'http://acme.test/' );
+		$writer->start();
+
+		$writer->about( 'http://foobar.test/Bananas' )
+			->say( 'a' )->is( 'http://foobar.test/Fruit' ); // shorthand name "a"
+
+		$writer->about( 'acme', 'Nuts' )
+			->say( 'acme', 'weight' )->value( '5.5', 'xsd', 'decimal' );
+
+		// redundant about( 'acme', 'Nuts' )
+		$writer->about( 'acme', 'Nuts' )
+			->say( 'acme', 'color' )->value( 'brown' );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'Triples', $rdf );
+	}
+
+	public function testPredicates() {
+		$writer = $this->newWriter();
+
+		$writer->prefix( '', 'http://acme.test/' ); // empty prefix
+		$writer->start();
+
+		$writer->about( 'http://foobar.test/Bananas' )
+			->a( 'http://foobar.test/Fruit' ) // shorthand function a()
+			->say( '', 'name' ) // empty prefix
+				->text( 'Banana' )
+			->say( '', 'name' ) // redundant say( '', 'name' )
+				->text( 'Banane', 'de' );
+
+		$writer->about( 'http://foobar.test/Apples' )
+			->say( '', 'name' ) // subsequent call to say( '', 'name' ) for a different subject
+				->text( 'Apple' );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'Predicates', $rdf );
+	}
+
+	public function testValues() {
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'acme', 'http://acme.test/' );
+		$writer->start();
+
+		$writer->about( 'http://foobar.test/Bananas' )
+			->say( 'acme', 'multi' )
+				->value( 'A' )
+				->value( 'B' )
+				->value( 'C' )
+			->say( 'acme', 'type' )
+				->value( 'foo', 'acme', 'thing' )
+				->value( '-5', 'xsd', 'integer' )
+				->value( '-5', 'xsd', 'decimal' )
+				->value( '-5', 'xsd', 'double' )
+				->value( 'true', 'xsd', 'boolean' )
+				->value( 'false', 'xsd', 'boolean' )
+			->say( 'acme', 'autotype' )
+				->value( -5 )
+				->value( 3.14 )
+				->value( true )
+				->value( false )
+			->say( 'acme', 'no-autotype' )
+				->value( -5, 'xsd', 'decimal' )
+				->value( 3.14, 'xsd', 'string' )
+				->value( true, 'xsd', 'string' )
+				->value( false, 'xsd', 'string' )
+			->say( 'acme', 'shorthand' )->value( 'foo' )
+			->say( 'acme', 'typed-shorthand' )->value( 'foo', 'acme', 'thing' );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'Values', $rdf );
+	}
+
+	public function testResources() {
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'acme', 'http://acme.test/' );
+		$writer->start();
+
+		$writer->about( 'acme', 'Bongos' )
+			->say( 'acme', 'sounds' )
+				->is( 'acme', 'Bing' )
+				->is( 'http://foobar.test/sound/Bang' );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'Resources', $rdf );
+
+	}
+
+	public function testTexts() {
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'acme', 'http://acme.test/' );
+		$writer->start();
+
+		$writer->about( 'acme', 'Bongos' )
+			->say( 'acme', 'sounds' )
+				->text( 'Bom', 'de' )
+				->text( 'Bam', 'en' );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'Texts', $rdf );
+	}
+
+	public function testNumbers() {
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'acme', 'http://acme.test/' );
+		$writer->start();
+
+		$writer->about( 'acme', 'Bongos' )
+			->say( 'acme', 'stock' )->value( 5, 'xsd', 'integer' )
+				->value( 7 )
+		->about( 'acme', 'Tablas' )
+			->say( 'acme', 'stock' )->value( 6 );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'Numbers', $rdf );
+	}
+
+	public function testEricMiller() {
+		// exampel taken from http://www.w3.org/2007/02/turtle/primer/
+
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'contact', 'http://www.w3.org/2000/10/swap/pim/contact#' );
+		$writer->start();
+
+		$writer->about( 'http://www.w3.org/People/EM/contact#me' )
+			->say( 'rdf', 'type' )->is( 'contact', 'Person' )
+			->say( 'contact', 'fullName' )->text( 'Eric Miller' )
+			->say( 'contact', 'mailbox' )->is( 'mailto:em@w3.org' )
+			->say( 'contact', 'personalTitle' )->text( 'Dr.' );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'EricMiller', $rdf );
+	}
+
+	public function testLabeledBlankNode() {
+		// exampel taken from http://www.w3.org/2007/02/turtle/primer/
+
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'exterms', 'http://www.example.org/terms/' );
+		$writer->prefix( 'exstaff', 'http://www.example.org/staffid/' );
+		$writer->start();
+
+		$writer->about( 'exstaff', '85740' )
+			->say( 'exterms', 'address' )->is( '_', $label = $writer->blank( 'johnaddress' ) )
+		->about( '_', $label )
+			->say( 'exterms', 'street' )->text( "1501 Grant Avenue" )
+			->say( 'exterms', 'city' )->text( "Bedfort" )
+			->say( 'exterms', 'state' )->text( "Massachusetts" )
+			->say( 'exterms', 'postalCode' )->text( "01730" );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'LabeledBlankNode', $rdf );
+	}
+
+	public function testNumberedBlankNodes() {
+		// exampel taken from http://www.w3.org/2007/02/turtle/primer/
+
+		$writer = $this->newWriter();
+
+		$writer->prefix( 'exterms', 'http://www.example.org/terms/' );
+		$writer->prefix( 'exstaff', 'http://www.example.org/staffid/' );
+		$writer->prefix( 'ex', 'http://example.org/packages/vocab#' );
+		$writer->start();
+
+		$writer->about( 'exstaff', 'Sue' )
+			->say( 'exterms', 'publication' )->is( '_', $label1 = $writer->blank() );
+		$writer->about( '_', $label1 )
+			->say( 'exterms', 'title' )->text( 'Antology of Time' );
+
+		$writer->about( 'exstaff', 'Jack' )
+			->say( 'exterms', 'publication' )->is( '_', $label2 = $writer->blank() );
+		$writer->about( '_', $label2 )
+			->say( 'exterms', 'title' )->text( 'Anthony of Time' );
+		$writer->finish();
+
+		$rdf = $writer->drain();
+		$this->assertOutputLines( 'NumberedBlankNode', $rdf );
+	}
+
+	//FIXME: test quoting/escapes!
+	//FIXME: test non-ascii literals!
+	//FIXME: test uerl-encoding
+	//FIXME: test IRIs!
+}
diff --git a/tests/phpunit/TurtleRdfWriterTest.php b/tests/phpunit/TurtleRdfWriterTest.php
new file mode 100644
index 0000000..404c1f1
--- /dev/null
+++ b/tests/phpunit/TurtleRdfWriterTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\RdfWriter;
+use Wikimedia\Purtle\TurtleRdfWriter;
+
+/**
+ * @covers Wikimedia\Purtle\TurtleRdfWriter
+ *
+ * @group Purtle
+ * @group RdfWriter
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class TurtleRdfWriterTest extends RdfWriterTestBase {
+
+	protected function getFileSuffix() {
+		return 'ttl';
+	}
+
+	/**
+	 * @return RdfWriter
+	 */
+	protected function newWriter() {
+		return new TurtleRdfWriter();
+	}
+}
diff --git a/tests/phpunit/UnicodeEscaperTest.php b/tests/phpunit/UnicodeEscaperTest.php
new file mode 100644
index 0000000..89a0382
--- /dev/null
+++ b/tests/phpunit/UnicodeEscaperTest.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\UnicodeEscaper;
+
+/**
+ * @covers Wikimedia\Purtle\UnicodeEscaper
+ *
+ * @group Purtle
+ * @group RdfWriter
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class UnicodeEscaperTest extends \PHPUnit_Framework_TestCase {
+
+	public function provideEscapeString() {
+		return array(
+			array( "Hello World", 'Hello World' ),
+			array( "Hello\nWorld", 'Hello\nWorld' ),
+			array( "Здравствулте мир", '\u0417\u0434\u0440\u0430\u0432\u0441\u0442\u0432\u0443\u043B\u0442\u0435 \u043C\u0438\u0440' ),
+			array( "여보세요 세계", '\uC5EC\uBCF4\uC138\uC694 \uC138\uACC4' ),
+			array( "你好世界", '\u4F60\u597D\u4E16\u754C' ),
+			array( "\xF0\x90\x8C\x80\xF0\x90\x8C\x81\xF0\x90\x8C\x82", '\U00010300\U00010301\U00010302' )
+		);
+	}
+
+	/**
+	 * @dataProvider provideEscapeString
+	 */
+	public function testEscapeString( $input, $expected ) {
+		$escaper = new UnicodeEscaper();
+
+		$this->assertEquals( $expected, $escaper->escapeString( $input ) );
+	}
+
+}
diff --git a/tests/phpunit/XmlRdfWriterTest.php b/tests/phpunit/XmlRdfWriterTest.php
new file mode 100644
index 0000000..02cd696
--- /dev/null
+++ b/tests/phpunit/XmlRdfWriterTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Wikimedia\Purtle\Tests;
+
+use Wikimedia\Purtle\XmlRdfWriter;
+use Wikimedia\Purtle\RdfWriter;
+
+/**
+ * @covers Wikimedia\Purtle\XmlRdfWriter
+ *
+ * @group Purtle
+ * @group RdfWriter
+ *
+ * @licence GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class XmlRdfWriterTest extends RdfWriterTestBase {
+
+	protected function getFileSuffix() {
+		return 'rdf';
+	}
+
+	/**
+	 * @return RdfWriter
+	 */
+	protected function newWriter() {
+		return new XmlRdfWriter();
+	}
+}