1 files changed, 209 insertions, 150 deletions

diff --git a/maintenance/parserTests.inc b/maintenance/parserTests.inc
index c85220d0..ddf8b89a 100644
--- a/maintenance/parserTests.inc
+++ b/maintenance/parserTests.inc
@@ -20,8 +20,7 @@
 /**
  * @todo Make this more independent of the configuration (and if possible the database)
  * @todo document
- * @package MediaWiki
- * @subpackage Maintenance
+ * @addtogroup Maintenance
  */
 
 /** */
@@ -29,46 +28,32 @@ $options = array( 'quick', 'color', 'quiet', 'help', 'show-output', 'record' );
 $optionsWithArgs = array( 'regex' );
 
 require_once( 'commandLine.inc' );
-require_once( "$IP/includes/ObjectCache.php" );
-require_once( "$IP/includes/BagOStuff.php" );
-require_once( "$IP/includes/Hooks.php" );
 require_once( "$IP/maintenance/parserTestsParserHook.php" );
 require_once( "$IP/maintenance/parserTestsStaticParserHook.php" );
 require_once( "$IP/maintenance/parserTestsParserTime.php" );
 
 /**
- * @package MediaWiki
- * @subpackage Maintenance
+ * @addtogroup Maintenance
  */
 class ParserTest {
 	/**
 	 * boolean $color whereas output should be colorized
-	 * @private
 	 */
-	var $color;
-
-	/**
-	 * boolean $lightcolor whereas output should use light colors
-	 * @private
-	 */
-	var $lightcolor;
+	private $color;
 
 	/**
 	 * boolean $showOutput Show test output
 	 */
-	var $showOutput;
+	private $showOutput;
 
 	/**
 	 * Sets terminal colorization and diff/quick modes depending on OS and
 	 * command-line options (--color and --quick).
-	 *
-	 * @public
 	 */
-	function ParserTest() {
+	public function ParserTest() {
 		global $options;
 
 		# Only colorize output if stdout is a terminal.
-		$this->lightcolor = false;
 		$this->color = !wfIsWindows() && posix_isatty(1);
 
 		if( isset( $options['color'] ) ) {
@@ -76,9 +61,6 @@ class ParserTest {
 			case 'no':
 				$this->color = false;
 				break;
-			case 'light':
-				$this->lightcolor = true;
-				# Fall through
 			case 'yes':
 			default:
 				$this->color = true;
@@ -86,11 +68,16 @@ class ParserTest {
 			}
 		}
 		$this->term = $this->color
-			? new AnsiTermColorer( $this->lightcolor )
+			? new AnsiTermColorer()
 			: new DummyTermColorer();
 
 		$this->showDiffs = !isset( $options['quick'] );
-		$this->quiet = isset( $options['quiet'] );
+		$this->showProgress = !isset( $options['quiet'] );
+		$this->showFailure = !(
+			isset( $options['quiet'] )
+			&& ( isset( $options['record'] )
+				|| isset( $options['compare'] ) ) ); // redundant output
+		
 		$this->showOutput = isset( $options['show-output'] );
 
 
@@ -100,22 +87,23 @@ class ParserTest {
 			# Matches anything
 			$this->regex = '';
 		}
-		
+
 		if( isset( $options['record'] ) ) {
 			$this->recorder = new DbTestRecorder( $this->term );
+		} elseif( isset( $options['compare'] ) ) {
+			$this->recorder = new DbTestPreviewer( $this->term );
 		} else {
 			$this->recorder = new TestRecorder( $this->term );
 		}
-		
+
 		$this->hooks = array();
 		$this->functionHooks = array();
 	}
 
 	/**
 	 * Remove last character if it is a newline
-	 * @private
 	 */
-	function chomp($s) {
+	private function chomp($s) {
 		if (substr($s, -1) === "\n") {
 			return substr($s, 0, -1);
 		}
@@ -134,26 +122,27 @@ class ParserTest {
 	 *
 	 * @param array of strings $filenames
 	 * @return bool True if passed all tests, false if any tests failed.
-	 * @public
 	 */
-	function runTestsFromFiles( $filenames ) {
+	public function runTestsFromFiles( $filenames ) {
 		$this->recorder->start();
 		$ok = true;
 		foreach( $filenames as $filename ) {
 			$ok = $this->runFile( $filename ) && $ok;
 		}
-		$this->recorder->end();
 		$this->recorder->report();
+		$this->recorder->end();
 		return $ok;
 	}
-	
+
 	private function runFile( $filename ) {
 		$infile = fopen( $filename, 'rt' );
 		if( !$infile ) {
 			wfDie( "Couldn't open $filename\n" );
 		} else {
+			global $IP;
+			$relative = wfRelativePath( $filename, $IP );
 			print $this->term->color( 1 ) .
-				"Reading tests from \"$filename\"..." .
+				"Reading tests from \"$relative\"..." .
 				$this->term->reset() .
 				"\n";
 		}
@@ -164,6 +153,7 @@ class ParserTest {
 		$ok = true;
 		while( false !== ($line = fgets( $infile ) ) ) {
 			$n++;
+			$matches = array();
 			if( preg_match( '/^!!\s*(\w+)/', $line, $matches ) ) {
 				$section = strtolower( $matches[1] );
 				if( $section == 'endarticle') {
@@ -250,7 +240,9 @@ class ParserTest {
 				$data[$section] .= $line;
 			}
 		}
-		print "\n";
+		if ( $this->showProgress ) {
+			print "\n";
+		}
 		return $ok;
 	}
 
@@ -263,8 +255,8 @@ class ParserTest {
 	 * @param string $result Result to output
 	 * @return bool
 	 */
-	function runTest( $desc, $input, $result, $opts ) {
-		if( !$this->quiet ) {
+	private function runTest( $desc, $input, $result, $opts ) {
+		if( $this->showProgress ) {
 			$this->showTesting( $desc );
 		}
 
@@ -278,6 +270,7 @@ class ParserTest {
 			$options->setUseTex(true);
 		}
 
+		$m = array();
 		if (preg_match('/title=\[\[(.*)\]\]/', $opts, $m)) {
 			$titleText = $m[1];
 		}
@@ -295,9 +288,10 @@ class ParserTest {
 			$parser->setFunctionHook( $tag, $callback );
 		}
 		wfRunHooks( 'ParserTestParser', array( &$parser ) );
-		
+
 		$title =& Title::makeTitle( NS_MAIN, $titleText );
 
+		$matches = array();
 		if (preg_match('/\\bpst\\b/i', $opts)) {
 			$out = $parser->preSaveTransform( $input, $title, $user, $options );
 		} elseif (preg_match('/\\bmsg\\b/i', $opts)) {
@@ -336,12 +330,10 @@ class ParserTest {
 	/**
 	 * Set up the global variables for a consistent environment for each test.
 	 * Ideally this should replace the global configuration entirely.
-	 *
-	 * @private
 	 */
-	function setupGlobals($opts = '') {
+	private function setupGlobals($opts = '') {
 		# Save the prefixed / quoted table names for later use when we make the temporaries.
-		$db =& wfGetDB( DB_READ );
+		$db = wfGetDB( DB_READ );
 		$this->oldTableNames = array();
 		foreach( $this->listTables() as $table ) {
 			$this->oldTableNames[$table] = $db->tableName( $table );
@@ -349,17 +341,19 @@ class ParserTest {
 		if( !isset( $this->uploadDir ) ) {
 			$this->uploadDir = $this->setupUploadDir();
 		}
-		
+
+		$m = array();
 		if( preg_match( '/language=([a-z]+(?:_[a-z]+)?)/', $opts, $m ) ) {
 			$lang = $m[1];
 		} else {
 			$lang = 'en';
 		}
 
-		if( preg_match( '/variant=([a-z]+(?:-[a-z]+)?)/', $opts, $m ) )
+		if( preg_match( '/variant=([a-z]+(?:-[a-z]+)?)/', $opts, $m ) ) {
 			$variant = $m[1];
-		else 
+		} else {
 			$variant = false;
+		}
 
 
 		$settings = array(
@@ -408,10 +402,12 @@ class ParserTest {
 		$wgUser = new User();
 	}
 
-	# List of temporary tables to create, without prefix
-	# Some of these probably aren't necessary
-	function listTables() {
-		$tables = array('user', 'page', 'revision', 'text',
+	/**
+	 * List of temporary tables to create, without prefix.
+	 * Some of these probably aren't necessary.
+	 */
+	private function listTables() {
+		$tables = array('user', 'page', 'page_restrictions', 'revision', 'text',
 			'pagelinks', 'imagelinks', 'categorylinks',
 			'templatelinks', 'externallinks', 'langlinks',
 			'site_stats', 'hitcounter',
@@ -422,14 +418,11 @@ class ParserTest {
 			'objectcache', 'job', 'redirect',
 			'querycachetwo'
 		);
-
-		// FIXME manually adding additional table for the tasks extension
-		// we probably need a better software wide system to register new
-		// tables.
-		global $wgExtensionFunctions;
-		if( in_array('wfTasksExtension' , $wgExtensionFunctions ) ) {
-			$tables[] = 'tasks';
-		}
+		
+		// Allow extensions to add to the list of tables to duplicate;
+		// may be necessary if they hook into page save or other code
+		// which will require them while running tests.
+		wfRunHooks( 'ParserTestTables', array( &$tables ) );
 
 		return $tables;
 	}
@@ -438,10 +431,8 @@ class ParserTest {
 	 * Set up a temporary set of wiki tables to work with for the tests.
 	 * Currently this will only be done once per run, and any changes to
 	 * the db will be visible to later tests in the run.
-	 *
-	 * @private
 	 */
-	function setupDatabase() {
+	private function setupDatabase() {
 		static $setupDB = false;
 		global $wgDBprefix;
 
@@ -449,7 +440,7 @@ class ParserTest {
 		if (!$setupDB && $wgDBprefix === 'parsertest_') {
 			# oh teh horror
 			$GLOBALS['wgLoadBalancer'] = LoadBalancer::newFromParams( $GLOBALS['wgDBservers'] );
-			$db =& wfGetDB( DB_MASTER );
+			$db = wfGetDB( DB_MASTER );
 
 			$tables = $this->listTables();
 
@@ -525,7 +516,7 @@ class ParserTest {
 				'img_minor_mime'  => "jpeg",
 				'img_metadata'    => serialize( array() ),
 				) );
-				
+
 			# Update certain things in site_stats
 			$db->insert( 'site_stats', array( 'ss_row_id' => 1, 'ss_images' => 1, 'ss_good_articles' => 1 ) );
 
@@ -537,9 +528,8 @@ class ParserTest {
 	 * Create a dummy uploads directory which will contain a couple
 	 * of files in order to pass existence tests.
 	 * @return string The directory
-	 * @private
 	 */
-	function setupUploadDir() {
+	private function setupUploadDir() {
 		global $IP;
 
 		$dir = wfTempDir() . "/mwParser-" . mt_rand() . "-images";
@@ -561,10 +551,8 @@ class ParserTest {
 	/**
 	 * Restore default values and perform any necessary clean-up
 	 * after each test runs.
-	 *
-	 * @private
 	 */
-	function teardownGlobals() {
+	private function teardownGlobals() {
 		foreach( $this->savedGlobals as $var => $val ) {
 			$GLOBALS[$var] = $val;
 		}
@@ -576,11 +564,10 @@ class ParserTest {
 
 	/**
 	 * Remove the dummy uploads directory
-	 * @private
 	 */
-	function teardownUploadDir( $dir ) {
+	private function teardownUploadDir( $dir ) {
 		// delete the files first, then the dirs.
-		self::deleteFiles( 
+		self::deleteFiles(
 			array (
 				"$dir/3/3a/Foobar.jpg",
 				"$dir/thumb/3/3a/Foobar.jpg/180px-Foobar.jpg",
@@ -589,9 +576,9 @@ class ParserTest {
 				"$dir/thumb/3/3a/Foobar.jpg/120px-Foobar.jpg",
 			)
 		);
-		    
+
 		self::deleteDirs(
-			array ( 
+			array (
 				"$dir/3/3a",
 				"$dir/3",
 				"$dir/thumb/6/65",
@@ -616,7 +603,7 @@ class ParserTest {
 			}
 		}
 	}
-	
+
 	/**
 	 * @desc delete the specified directories, if they exist. Must be empty.
 	 * @param array $dirs full paths to directories to delete.
@@ -628,12 +615,11 @@ class ParserTest {
 			}
 		}
 	}
-	
+
 	/**
 	 * "Running test $desc..."
-	 * @private
 	 */
-	function showTesting( $desc ) {
+	private function showTesting( $desc ) {
 		print "Running test $desc... ";
 	}
 
@@ -642,10 +628,9 @@ class ParserTest {
 	 *
 	 * @param string $desc The test name
 	 * @return bool
-	 * @private
 	 */
-	function showSuccess( $desc ) {
-		if( !$this->quiet ) {
+	private function showSuccess( $desc ) {
+		if( $this->showProgress ) {
 			print $this->term->color( '1;32' ) . 'PASSED' . $this->term->reset() . "\n";
 		}
 		return true;
@@ -659,22 +644,23 @@ class ParserTest {
 	 * @param string $result Expected HTML output
 	 * @param string $html Actual HTML output
 	 * @return bool
-	 * @private
 	 */
-	function showFailure( $desc, $result, $html ) {
-		if( $this->quiet ) {
-			# In quiet mode we didn't show the 'Testing' message before the
-			# test, in case it succeeded. Show it now:
-			$this->showTesting( $desc );
-		}
-		print $this->term->color( '1;31' ) . 'FAILED!' . $this->term->reset() . "\n";
-		if ( $this->showOutput ) {
-			print "--- Expected ---\n$result\n--- Actual ---\n$html\n";
-		}
-		if( $this->showDiffs ) {
-			print $this->quickDiff( $result, $html );
-			if( !$this->wellFormed( $html ) ) {
-				print "XML error: $this->mXmlError\n";
+	private function showFailure( $desc, $result, $html ) {
+		if( $this->showFailure ) {
+			if( !$this->showProgress ) {
+				# In quiet mode we didn't show the 'Testing' message before the
+				# test, in case it succeeded. Show it now:
+				$this->showTesting( $desc );
+			}
+			print $this->term->color( '31' ) . 'FAILED!' . $this->term->reset() . "\n";
+			if ( $this->showOutput ) {
+				print "--- Expected ---\n$result\n--- Actual ---\n$html\n";
+			}
+			if( $this->showDiffs ) {
+				print $this->quickDiff( $result, $html );
+				if( !$this->wellFormed( $html ) ) {
+					print "XML error: $this->mXmlError\n";
+				}
 			}
 		}
 		return false;
@@ -689,9 +675,8 @@ class ParserTest {
 	 * @param string $inFileTail Tailing for the input file name
 	 * @param string $outFileTail Tailing for the output file name
 	 * @return string
-	 * @private
 	 */
-	function quickDiff( $input, $output, $inFileTail='expected', $outFileTail='actual' ) {
+	private function quickDiff( $input, $output, $inFileTail='expected', $outFileTail='actual' ) {
 		$prefix = wfTempDir() . "/mwParser-" . mt_rand();
 
 		$infile = "$prefix-$inFileTail";
@@ -712,9 +697,8 @@ class ParserTest {
 	 *
 	 * @param string $data
 	 * @param string $filename
-	 * @private
 	 */
-	function dumpToFile( $data, $filename ) {
+	private function dumpToFile( $data, $filename ) {
 		$file = fopen( $filename, "wt" );
 		fwrite( $file, $data . "\n" );
 		fclose( $file );
@@ -726,9 +710,8 @@ class ParserTest {
 	 *
 	 * @param string $text
 	 * @return string
-	 * @private
 	 */
-	function colorDiff( $text ) {
+	private function colorDiff( $text ) {
 		return preg_replace(
 			array( '/^(-.*)$/m', '/^(\+.*)$/m' ),
 			array( $this->term->color( 34 ) . '$1' . $this->term->reset(),
@@ -741,9 +724,8 @@ class ParserTest {
 	 * @param string $name the title, including any prefix
 	 * @param string $text the article text
 	 * @param int $line the input line number, for reporting errors
-	 * @private
 	 */
-	function addArticle($name, $text, $line) {
+	private function addArticle($name, $text, $line) {
 		$this->setupGlobals();
 		$title = Title::newFromText( $name );
 		if ( is_null($title) ) {
@@ -759,7 +741,7 @@ class ParserTest {
 		$art->insertNewArticle($text, '', false, false );
 		$this->teardownGlobals();
 	}
-	
+
 	/**
 	 * Steal a callback function from the primary parser, save it for
 	 * application to our scary parser. If the hook is not installed,
@@ -775,7 +757,6 @@ class ParserTest {
 		}
 	}
 
-	
 	/**
 	 * Steal a callback function from the primary parser, save it for
 	 * application to our scary parser. If the hook is not installed,
@@ -798,9 +779,8 @@ class ParserTest {
 	 * @param string $text the text to tidy
 	 * @return string
 	 * @static
-	 * @private
 	 */
-	function tidy( $text ) {
+	private function tidy( $text ) {
 		global $wgUseTidy;
 		if ($wgUseTidy) {
 			$text = Parser::tidy($text);
@@ -808,7 +788,7 @@ class ParserTest {
 		return $text;
 	}
 
-	function wellFormed( $text ) {
+	private function wellFormed( $text ) {
 		$html =
 			Sanitizer::hackDocType() .
 			'<html>' .
@@ -832,7 +812,7 @@ class ParserTest {
 		return true;
 	}
 
-	function extractFragment( $text, $position ) {
+	private function extractFragment( $text, $position ) {
 		$start = max( 0, $position - 10 );
 		$before = $position - $start;
 		$fragment = '...' .
@@ -855,23 +835,21 @@ class ParserTest {
 			$this->term->color( 0 );
 		return "$display\n$caret";
 	}
-	
 }
 
 class AnsiTermColorer {
-	function __construct( $light ) {
-		$this->light = $light;
+	function __construct() {
 	}
-	
+
 	/**
 	 * Return ANSI terminal escape code for changing text attribs/color
 	 *
 	 * @param string $color Semicolon-separated list of attribute/color codes
 	 * @return string
-	 * @private
 	 */
-	function color( $color ) {
-		$light = $this->light ? "1;" : "";
+	public function color( $color ) {
+		global $wgCommandLineDarkBg;
+		$light = $wgCommandLineDarkBg ? "1;" : "0;";
 		return "\x1b[{$light}{$color}m";
 	}
 
@@ -879,20 +857,19 @@ class AnsiTermColorer {
 	 * Return ANSI terminal escape code for restoring default text attributes
 	 *
 	 * @return string
-	 * @private
 	 */
-	function reset() {
-		return "\x1b[0m";
+	public function reset() {
+		return $this->color( 0 );
 	}
 }
 
 /* A colour-less terminal */
 class DummyTermColorer {
-	function color( $color ) {
+	public function color( $color ) {
 		return '';
 	}
-	
-	function reset() {
+
+	public function reset() {
 		return '';
 	}
 }
@@ -901,21 +878,21 @@ class TestRecorder {
 	function __construct( $term ) {
 		$this->term = $term;
 	}
-	
+
 	function start() {
 		$this->total = 0;
 		$this->success = 0;
 	}
-	
+
 	function record( $test, $result ) {
 		$this->total++;
 		$this->success += ($result ? 1 : 0);
 	}
-	
+
 	function end() {
 		// dummy
 	}
-	
+
 	function report() {
 		if( $this->total > 0 ) {
 			$this->reportPercentage( $this->success, $this->total );
@@ -923,14 +900,15 @@ class TestRecorder {
 			wfDie( "No tests found.\n" );
 		}
 	}
-	
+
 	function reportPercentage( $success, $total ) {
 		$ratio = wfPercent( 100 * $success / $total );
 		print $this->term->color( 1 ) . "Passed $success of $total tests ($ratio)... ";
 		if( $success == $total ) {
-			print $this->term->color( 32 ) . "PASSED!";
+			print $this->term->color( 32 ) . "ALL TESTS PASSED!";
 		} else {
-			print $this->term->color( 31 ) . "FAILED!";
+			$failed = $total - $success ;
+			print $this->term->color( 31 ) . "$failed tests failed!";
 		}
 		print $this->term->reset() . "\n";
 		return ($success == $total);
@@ -938,27 +916,33 @@ class TestRecorder {
 }
 
 class DbTestRecorder extends TestRecorder  {
-	private $db;      ///< Database connection to the main DB
-	private $curRun;  ///< run ID number for the current run
-	private $prevRun; ///< run ID number for the previous run, if any
-	
+	protected $db;      ///< Database connection to the main DB
+	protected $curRun;  ///< run ID number for the current run
+	protected $prevRun; ///< run ID number for the previous run, if any
+
 	function __construct( $term ) {
 		parent::__construct( $term );
 		$this->db = wfGetDB( DB_MASTER );
 	}
-	
+
 	/**
 	 * Set up result recording; insert a record for the run with the date
 	 * and all that fun stuff
 	 */
 	function start() {
 		parent::start();
-		
+
 		$this->db->begin();
-		
+
+		if( ! $this->db->tableExists( 'testrun' ) or ! $this->db->tableExists( 'testitem') ) {
+			print "WARNING> `testrun` table not found in database. Trying to create table.\n";
+			dbsource( 'testRunner.sql',  $this->db );
+			echo "OK, resuming.\n";
+		}
+
 		// We'll make comparisons against the previous run later...
 		$this->prevRun = $this->db->selectField( 'testrun', 'MAX(tr_id)' );
-		
+
 		$this->db->insert( 'testrun',
 			array(
 				'tr_date'        => $this->db->timestamp(),
@@ -970,7 +954,7 @@ class DbTestRecorder extends TestRecorder  {
 			__METHOD__ );
 		$this->curRun = $this->db->insertId();
 	}
-	
+
 	/**
 	 * Record an individual test item's success or failure to the db
 	 * @param string $test
@@ -986,7 +970,7 @@ class DbTestRecorder extends TestRecorder  {
 			),
 			__METHOD__ );
 	}
-	
+
 	/**
 	 * Commit transaction and clean up for result recording
 	 */
@@ -994,38 +978,40 @@ class DbTestRecorder extends TestRecorder  {
 		$this->db->commit();
 		parent::end();
 	}
-	
+
 	function report() {
 		if( $this->prevRun ) {
 			$table = array(
 				array( 'previously failing test(s) now PASSING! :)', 0, 1 ),
 				array( 'previously PASSING test(s) removed o_O', 1, null ),
 				array( 'new PASSING test(s) :)', null, 1 ),
-				
+
 				array( 'previously passing test(s) now FAILING! :(', 1, 0 ),
 				array( 'previously FAILING test(s) removed O_o', 0, null ),
 				array( 'new FAILING test(s) :(', null, 0 ),
+				array( 'still FAILING test(s) :(', 0, 0 ),
 			);
 			foreach( $table as $criteria ) {
 				list( $label, $before, $after ) = $criteria;
 				$differences = $this->compareResult( $before, $after );
 				if( $differences ) {
 					$count = count($differences);
-					printf( "%4d %s\n", $count, $label );
-					foreach ($differences as $differing_test_name) {
-						print "      * $differing_test_name\n";
+					printf( "\n%4d %s\n", $count, $label );
+					foreach ($differences as $differing_test_name => $statusInfo) {
+						print "      * $differing_test_name  [$statusInfo]\n";
 					}
 				}
 			}
 		} else {
 			print "No previous test runs to compare against.\n";
 		}
+		print "\n";
 		parent::report();
 	}
-	
+
 	/**
-	 ** @desc: Returns an array of the test names with changed results, based on the specified
-	 **        before/after criteria.
+	 ** Returns an array of the test names with changed results, based on the specified
+	 ** before/after criteria.
 	 */
 	private function compareResult( $before, $after ) {
 		$testitem = $this->db->tableName( 'testitem' );
@@ -1033,7 +1019,7 @@ class DbTestRecorder extends TestRecorder  {
 		$curRun = intval( $this->curRun );
 		$prevStatus = $this->condition( $before );
 		$curStatus = $this->condition( $after );
-		
+
 		// note: requires mysql >= ver 4.1 for subselects
 		if( is_null( $after ) ) {
 			$sql = "
@@ -1055,14 +1041,77 @@ class DbTestRecorder extends TestRecorder  {
 		$result = $this->db->query( $sql, __METHOD__ );
 		$retval = array();
 		while ($row = $this->db->fetchObject( $result )) {
-			$retval[] = $row->t;
+			$testname = $row->t;
+			$retval[$testname] = $this->getTestStatusInfo( $testname, $after, $curRun );
 		}
 		$this->db->freeResult( $result );
 		return $retval;
 	}
-	
+
+	/**
+	 ** Returns a string giving information about when a test last had a status change.
+	 ** Could help to track down when regressions were introduced, as distinct from tests
+	 ** which have never passed (which are more change requests than regressions).
+	 */
+	private function getTestStatusInfo($testname, $after, $curRun) {
+
+		// If we're looking at a test that has just been removed, then say when it first appeared.
+		if ( is_null( $after ) ) {
+			$changedRun = $this->db->selectField ( 'testitem',
+												   'MIN(ti_run)',
+												   array( 'ti_name' => $testname ),
+												   __METHOD__ );
+			$appear = $this->db->selectRow ( 'testrun',
+											 array( 'tr_date', 'tr_mw_version' ),
+											 array( 'tr_id' => $changedRun ),
+											 __METHOD__ );
+			return "First recorded appearance: "
+			       . date( "d-M-Y H:i:s",  strtotime ( $appear->tr_date ) )
+			       .  ", " . $appear->tr_mw_version;
+		}
+
+		// Otherwise, this test has previous recorded results.
+		// See when this test last had a different result to what we're seeing now.
+		$changedRun = $this->db->selectField ( 'testitem',
+											   'MAX(ti_run)',
+											   array( 
+											       'ti_name'    => $testname,
+											       'ti_success' => ($after ? "0" : "1"),
+											       "ti_run != " . $this->db->addQuotes ( $curRun )
+												), 
+												__METHOD__ );
+
+		// If no record of ever having had a different result.
+		if ( is_null ( $changedRun ) ) {
+			if ($after == "0") {
+				return "Has never passed";
+			} else {
+				return "Has never failed";
+			}
+		}
+
+		// Otherwise, we're looking at a test whose status has changed.
+		// (i.e. it used to work, but now doesn't; or used to fail, but is now fixed.)
+		// In this situation, give as much info as we can as to when it changed status.
+		$pre  = $this->db->selectRow ( 'testrun',
+										array( 'tr_date', 'tr_mw_version' ),
+										array( 'tr_id' => $changedRun ),
+										__METHOD__ );
+		$post = $this->db->selectRow ( 'testrun',
+										array( 'tr_date', 'tr_mw_version' ),
+										array( "tr_id > " . $this->db->addQuotes ( $changedRun) ),
+										__METHOD__,
+										array( "LIMIT" => 1, "ORDER BY" => 'tr_id' )
+									 );
+
+		return ( $after == "0" ? "Introduced" : "Fixed" ) . " between "
+				. date( "d-M-Y H:i:s",  strtotime ( $pre->tr_date ) ) .  ", " . $pre->tr_mw_version
+				. " and "
+				. date( "d-M-Y H:i:s",  strtotime ( $post->tr_date  ) ) .  ", " . $post->tr_mw_version ;
+	}
+
 	/**
-	 ** @desc: Helper function for compareResult() database querying.
+	 ** Helper function for compareResult() database querying.
 	 */
 	private function condition( $value ) {
 		if( is_null( $value ) ) {
@@ -1074,4 +1123,14 @@ class DbTestRecorder extends TestRecorder  {
 
 }
 
+class DbTestPreviewer extends DbTestRecorder  {
+	/**
+	 * Commit transaction and clean up for result recording
+	 */
+	function end() {
+		$this->db->rollback();
+		TestRecorder::end();
+	}
+}
+
 ?>