#6622 Logger refactoring: Separated error and exception handling from logging

- the error handler logs warnings and notices, and turns errors into exceptions (`ErrorException`)
- the exception handler catches all uncatched exceptions and display them to the user (HTML or CLI)
- the "screen" logging backend has been removed
- I've normalized exceptions/errors shown to the user in HTML (wether they are catched by the FrontController or not)

17 files changed, 171 insertions, 341 deletions

diff --git a/config/global.php b/config/global.php
index 933c28daad..5810779925 100644
--- a/config/global.php
+++ b/config/global.php
@@ -4,7 +4,6 @@ use Interop\Container\ContainerInterface;
 use Monolog\Logger;
 use Piwik\Common;
 use Piwik\Log;
-use Piwik\Log\Handler\StdErrHandler;
 
 return array(
 
@@ -27,54 +26,38 @@ return array(
     // Log
     'Psr\Log\LoggerInterface' => DI\object('Monolog\Logger')
         ->constructor('piwik', DI\link('log.handlers'), DI\link('log.processors')),
-    'Piwik\Log' => DI\object()
-        ->constructor(DI\link('Psr\Log\LoggerInterface')),
     'log.handlers' => DI\factory(function (ContainerInterface $c) {
         if ($c->has('old_config.log.log_writers')) {
             $writerNames = $c->get('old_config.log.log_writers');
-        }
-        if (empty($writerNames)) {
+        } else {
             return array();
         }
-
         $classes = array(
             'file'     => 'Piwik\Log\Handler\FileHandler',
-            'screen'   => 'log.handlers.stdout',
             'database' => 'Piwik\Log\Handler\DatabaseHandler',
         );
-
         $writerNames = array_map('trim', $writerNames);
         $writers = array();
         foreach ($writerNames as $writerName) {
             if (isset($classes[$writerName])) {
-                $class = $classes[$writerName];
-                $writers[$writerName] = $c->get($class);
+                $writers[$writerName] = $c->get($classes[$writerName]);
             }
         }
-
-        // Always add the stderr handler
-        $isLoggingToStdOut = isset($writers['screen']);
-        $writers['stderr'] = new StdErrHandler($c->get('Piwik\Log\Formatter\ExceptionHtmlFormatter'), $isLoggingToStdOut);
-
         return array_values($writers);
     }),
     'log.processors' => array(
         DI\link('Piwik\Log\Processor\ClassNameProcessor'),
         DI\link('Piwik\Log\Processor\RequestIdProcessor'),
+        DI\link('Piwik\Log\Processor\ExceptionToTextProcessor'),
         DI\link('Piwik\Log\Processor\SprintfProcessor'),
         DI\link('Monolog\Processor\PsrLogMessageProcessor'),
     ),
     'Piwik\Log\Handler\FileHandler' => DI\object()
         ->constructor(DI\link('log.file.filename'), DI\link('log.level'))
-        ->method('setFormatter', DI\link('Piwik\Log\Formatter\LineMessageFormatter'))
-        ->method('pushProcessor', DI\link('Piwik\Log\Processor\ExceptionToTextProcessor')),
+        ->method('setFormatter', DI\link('Piwik\Log\Formatter\LineMessageFormatter')),
     'Piwik\Log\Handler\DatabaseHandler' => DI\object()
         ->constructor(DI\link('log.level'))
-        ->method('setFormatter', DI\link('Piwik\Log\Formatter\LineMessageFormatter'))
-        ->method('pushProcessor', DI\link('Piwik\Log\Processor\ExceptionToTextProcessor')),
-    'log.handlers.stdout' => DI\object('Monolog\Handler\StreamHandler')
-        ->constructor('php://output', DI\link('log.level'))
-        ->method('setFormatter', DI\link('Piwik\Log\Formatter\ExceptionHtmlFormatter')),
+        ->method('setFormatter', DI\link('Piwik\Log\Formatter\LineMessageFormatter')),
     'log.level' => DI\factory(function (ContainerInterface $c) {
         if ($c->get('log.disabled')) {
             return Log::getMonologLevel(Log::NONE);
@@ -123,8 +106,6 @@ return array(
 
         return $logPath;
     }),
-    'Piwik\Log\Formatter\ExceptionHtmlFormatter' => DI\object()
-        ->constructor(DI\link('Piwik\Log\Formatter\LineMessageFormatter')),
     'Piwik\Log\Formatter\LineMessageFormatter' => DI\object()
         ->constructor(DI\link('log.format')),
     'log.format' => DI\factory(function (ContainerInterface $c) {
diff --git a/console b/console
index e3738ab10a..1b4d7c7e08 100755
--- a/console
+++ b/console
@@ -25,5 +25,12 @@ if (!Piwik\Common::isPhpCliMode()) {
     exit;
 }
 
+if (!defined('PIWIK_ENABLE_ERROR_HANDLER') || PIWIK_ENABLE_ERROR_HANDLER) {
+    require_once PIWIK_INCLUDE_PATH . '/core/Error.php';
+    \Piwik\Error::setErrorHandler();
+    require_once PIWIK_INCLUDE_PATH . '/core/ExceptionHandler.php';
+    \Piwik\ExceptionHandler::setUp();
+}
+
 $console = new Piwik\Console();
 $console->run();
\ No newline at end of file
diff --git a/core/Error.php b/core/Error.php
index 7f5e740f38..0dd346244f 100644
--- a/core/Error.php
+++ b/core/Error.php
@@ -4,11 +4,11 @@
  *
  * @link http://piwik.org
  * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- *
  */
+
 namespace Piwik;
 
-require_once PIWIK_INCLUDE_PATH . '/core/Log.php';
+use Piwik\Exception\ErrorException;
 
 /**
  * Piwik's error handler function.
@@ -71,9 +71,6 @@ class Error
             return;
         }
 
-        $error = new \ErrorException($errstr, 0, $errno, $errfile, $errline);
-        Log::error($error);
-
         switch ($errno) {
             case E_ERROR:
             case E_PARSE:
@@ -82,7 +79,10 @@ class Error
             case E_COMPILE_ERROR:
             case E_COMPILE_WARNING:
             case E_USER_ERROR:
-                exit;
+                // Convert the error to an exception with an HTML message
+                $e = new \Exception();
+                $message = self::getHtmlMessage($errno, $errstr, $errfile, $errline, $e->getTraceAsString());
+                throw new ErrorException($message, 0, $errno, $errfile, $errline);
                 break;
 
             case E_WARNING:
@@ -94,8 +94,37 @@ class Error
             case E_DEPRECATED:
             case E_USER_DEPRECATED:
             default:
-                // do not exit
+                Log::info(self::createLogMessage($errno, $errstr, $errfile, $errline));
                 break;
         }
     }
+
+    private static function createLogMessage($errno, $errstr, $errfile, $errline)
+    {
+        return sprintf(
+            "%s(%d): %s - %s",
+            $errfile,
+            $errline,
+            Error::getErrNoString($errno),
+            $errstr
+        );
+    }
+
+    private static function getHtmlMessage($errno, $errstr, $errfile, $errline, $trace)
+    {
+        $trace = Log::$debugBacktraceForTests ?: $trace;
+
+        $message = Error::getErrNoString($errno) . ' - ' . $errstr;
+
+        $html = "<strong>There is an error. Please report the message (Piwik " . (class_exists('Piwik\Version') ? Version::VERSION : '') . ")
+        and full backtrace in the <a href='?module=Proxy&action=redirect&url=http://forum.piwik.org' target='_blank'>Piwik forums</a> (please do a Search first as it might have been reported already!).</strong><br /><br/>
+        ";
+        $html .= "<strong>{$message}</strong> in <em>{$errfile}</em>";
+        $html .= " on line {$errline}<br />";
+        $html .= "<br />Backtrace:<div style=\"font-family:Courier;font-size:10pt\"><br />\n";
+        $html .= str_replace("\n", "<br />\n", $trace);
+        $html .= "</div>";
+
+        return $html;
+    }
 }
diff --git a/core/Exception/ErrorException.php b/core/Exception/ErrorException.php
new file mode 100644
index 0000000000..1673d8def8
--- /dev/null
+++ b/core/Exception/ErrorException.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Piwik\Exception;
+
+/**
+ * ErrorException
+ *
+ * @author Matthieu Napoli <matthieu@mnapoli.fr>
+ */
+class ErrorException extends \ErrorException
+{
+    public function isHtmlMessage()
+    {
+        return true;
+    }
+}
diff --git a/core/ExceptionHandler.php b/core/ExceptionHandler.php
index 8a10bc1e6b..e68a058e4a 100644
--- a/core/ExceptionHandler.php
+++ b/core/ExceptionHandler.php
@@ -8,6 +8,9 @@
  */
 namespace Piwik;
 
+use Exception;
+use Piwik\Plugins\CoreAdminHome\CustomLogo;
+
 /**
  * Contains Piwik's uncaught exception handler.
  */
@@ -15,11 +18,82 @@ class ExceptionHandler
 {
     public static function setUp()
     {
-        set_exception_handler(array('Piwik\ExceptionHandler', 'logException'));
+        set_exception_handler(array('Piwik\ExceptionHandler', 'handleException'));
+    }
+
+    public static function handleException(Exception $exception)
+    {
+        if (Common::isPhpCliMode()) {
+            self::dieWithCliError($exception);
+        }
+
+        self::dieWithHtmlErrorPage($exception);
+    }
+
+    public static function dieWithCliError(Exception $exception)
+    {
+        $message = $exception->getMessage();
+
+        if (!method_exists($exception, 'isHtmlMessage') || !$exception->isHtmlMessage()) {
+            $message = strip_tags(str_replace('<br />', PHP_EOL, $message));
+        }
+
+        $message = sprintf(
+            "Uncaught exception: %s\nin %s line %d\n%s\n",
+            $message,
+            $exception->getFile(),
+            $exception->getLine(),
+            $exception->getTraceAsString()
+        );
+
+        echo $message;
+
+        exit(1);
+    }
+
+    public static function dieWithHtmlErrorPage(Exception $exception)
+    {
+        Common::sendHeader('Content-Type: text/html; char1set=utf-8');
+
+        echo self::getErrorResponse($exception);
+
+        exit(1);
     }
 
-    public static function logException(\Exception $exception)
+    private static function getErrorResponse(Exception $ex)
     {
-        Log::error($exception);
+        $debugTrace = $ex->getTraceAsString();
+
+        $message = $ex->getMessage();
+
+        if (!method_exists($ex, 'isHtmlMessage') || !$ex->isHtmlMessage()) {
+            $message = Common::sanitizeInputValue($message);
+        }
+
+        $logo = new CustomLogo();
+
+        $logoHeaderUrl = false;
+        $logoFaviconUrl = false;
+        try {
+            $logoHeaderUrl = $logo->getHeaderLogoUrl();
+            $logoFaviconUrl = $logo->getPathUserFavicon();
+        } catch (Exception $ex) {
+            Log::debug($ex);
+        }
+
+        $result = Piwik_GetErrorMessagePage($message, $debugTrace, true, true, $logoHeaderUrl, $logoFaviconUrl);
+
+        /**
+         * Triggered before a Piwik error page is displayed to the user.
+         *
+         * This event can be used to modify the content of the error page that is displayed when
+         * an exception is caught.
+         *
+         * @param string &$result The HTML of the error page.
+         * @param Exception $ex The Exception displayed in the error page.
+         */
+        Piwik::postEvent('FrontController.modifyErrorPage', array(&$result, $ex));
+
+        return $result;
     }
 }
diff --git a/core/FrontController.php b/core/FrontController.php
index 7d1702315f..d536ab22a7 100644
--- a/core/FrontController.php
+++ b/core/FrontController.php
@@ -18,7 +18,6 @@ use Piwik\Http\Router;
 use Piwik\Plugin\Controller;
 use Piwik\Plugin\Report;
 use Piwik\Plugin\Widgets;
-use Piwik\Plugins\CoreAdminHome\CustomLogo;
 use Piwik\Session;
 
 /**
@@ -610,48 +609,4 @@ class FrontController extends Singleton
         Piwik::postEvent('Request.dispatch.end', array(&$result, $module, $action, $parameters));
         return $result;
     }
-
-    /**
-     * Returns HTML that displays an exception's error message (and possibly stack trace).
-     * The result of this method is echo'd by dispatch.php.
-     *
-     * @param Exception $ex The exception to use when generating the error page's HTML.
-     * @return string The HTML to echo.
-     */
-    public function getErrorResponse(Exception $ex)
-    {
-        $debugTrace = $ex->getTraceAsString();
-
-        $message = $ex->getMessage();
-
-        if (!method_exists($ex, 'isHtmlMessage') || !$ex->isHtmlMessage()) {
-            $message = Common::sanitizeInputValue($message);
-        }
-
-        $logo = new CustomLogo();
-
-        $logoHeaderUrl = false;
-        $logoFaviconUrl = false;
-        try {
-            $logoHeaderUrl = $logo->getHeaderLogoUrl();
-            $logoFaviconUrl = $logo->getPathUserFavicon();
-        } catch (Exception $ex) {
-            Log::debug($ex);
-        }
-
-        $result = Piwik_GetErrorMessagePage($message, $debugTrace, true, true, $logoHeaderUrl, $logoFaviconUrl);
-
-        /**
-         * Triggered before a Piwik error page is displayed to the user.
-         *
-         * This event can be used to modify the content of the error page that is displayed when
-         * an exception is caught.
-         *
-         * @param string &$result The HTML of the error page.
-         * @param Exception $ex The Exception displayed in the error page.
-         */
-        Piwik::postEvent('FrontController.modifyErrorPage', array(&$result, $ex));
-
-        return $result;
-    }
 }
diff --git a/core/Log/Formatter/ExceptionHtmlFormatter.php b/core/Log/Formatter/ExceptionHtmlFormatter.php
deleted file mode 100644
index d94190b089..0000000000
--- a/core/Log/Formatter/ExceptionHtmlFormatter.php
+++ /dev/null
@@ -1,65 +0,0 @@
-<?php
-/**
- * Piwik - free/libre analytics platform
- *
- * @link http://piwik.org
- * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- */
-
-namespace Piwik\Log\Formatter;
-
-use Piwik\Common;
-use Piwik\Error;
-use Piwik\Log;
-use Piwik\Version;
-
-/**
- * Formats a log message containing an exception object into an HTML response.
- */
-class ExceptionHtmlFormatter extends Formatter
-{
-    public function format(array $record)
-    {
-        if (! $this->contextContainsException($record)) {
-            return $this->next($record);
-        }
-
-        /** @var \Exception $exception */
-        $exception = $record['context']['exception'];
-
-        Common::sendHeader('Content-Type: text/html; charset=utf-8');
-
-        $trace = Log::$debugBacktraceForTests ?: $exception->getTraceAsString();
-
-        $message = $this->getMessage($exception);
-
-        $html = '';
-        $html .= "<div style='word-wrap: break-word; border: 3px solid red; padding:4px; width:70%; background-color:#FFFF96;'>
-        <strong>There is an error. Please report the message (Piwik " . (class_exists('Piwik\Version') ? Version::VERSION : '') . ")
-        and full backtrace in the <a href='?module=Proxy&action=redirect&url=http://forum.piwik.org' target='_blank'>Piwik forums</a> (please do a Search first as it might have been reported already!).</strong><br /><br/>
-        ";
-        $html .= "<em>{$message}</em> in <strong>{$exception->getFile()}</strong>";
-        $html .= " on line <strong>{$exception->getLine()}</strong>\n";
-        $html .= "<br /><br />Backtrace --&gt;<div style=\"font-family:Courier;font-size:10pt\"><br />\n";
-        $html .= str_replace("\n", "<br />\n", $trace);
-        $html .= "</div>";
-        $html .= "</div>\n";
-
-        return $html;
-    }
-
-    private function contextContainsException($record)
-    {
-        return isset($record['context']['exception'])
-            && $record['context']['exception'] instanceof \Exception;
-    }
-
-    private function getMessage(\Exception $exception)
-    {
-        if ($exception instanceof \ErrorException) {
-            return Error::getErrNoString($exception->getSeverity()) . ' - ' . $exception->getMessage();
-        }
-
-        return $exception->getMessage();
-    }
-}
diff --git a/core/Log/Formatter/Formatter.php b/core/Log/Formatter/Formatter.php
deleted file mode 100644
index 6f5ac67e64..0000000000
--- a/core/Log/Formatter/Formatter.php
+++ /dev/null
@@ -1,60 +0,0 @@
-<?php
-/**
- * Piwik - free/libre analytics platform
- *
- * @link http://piwik.org
- * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- */
-
-namespace Piwik\Log\Formatter;
-
-use Monolog\Formatter\FormatterInterface;
-
-/**
- * Formats a log message.
- *
- * Follows the Chain of responsibility design pattern.
- */
-abstract class Formatter implements FormatterInterface
-{
-    /**
-     * @var Formatter|null
-     */
-    protected $next;
-
-    public function __construct(Formatter $next = null)
-    {
-        $this->next = $next;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function formatBatch(array $records)
-    {
-        foreach ($records as $key => $record) {
-            $records[$key] = $this->format($record);
-        }
-
-        return $records;
-    }
-
-    /**
-     * Chain of responsibility pattern.
-     *
-     * @param Formatter $formatter
-     */
-    public function setNext(Formatter $formatter)
-    {
-        $this->next = $formatter;
-    }
-
-    protected function next(array $record)
-    {
-        if (! $this->next) {
-            throw new \RuntimeException('No next formatter to call');
-        }
-
-        return $this->next->format($record);
-    }
-}
diff --git a/core/Log/Formatter/LineMessageFormatter.php b/core/Log/Formatter/LineMessageFormatter.php
index 08f368dfc5..7c38fc32df 100644
--- a/core/Log/Formatter/LineMessageFormatter.php
+++ b/core/Log/Formatter/LineMessageFormatter.php
@@ -8,10 +8,12 @@
 
 namespace Piwik\Log\Formatter;
 
+use Monolog\Formatter\FormatterInterface;
+
 /**
- * Formats a log message into a line of text.
+ * Formats a log message into a line of text using our custom Piwik log format.
  */
-class LineMessageFormatter extends Formatter
+class LineMessageFormatter implements FormatterInterface
 {
     /**
      * The log message format string that turns a tag name, date-time and message into
@@ -49,6 +51,15 @@ class LineMessageFormatter extends Formatter
         return $message;
     }
 
+    public function formatBatch(array $records)
+    {
+        foreach ($records as $key => $record) {
+            $records[$key] = $this->format($record);
+        }
+
+        return $records;
+    }
+
     private function prefixMessageWithRequestId(array $record)
     {
         $requestId = isset($record['extra']['request_id']) ? $record['extra']['request_id'] : '';
diff --git a/core/Log/Handler/StdErrHandler.php b/core/Log/Handler/StdErrHandler.php
deleted file mode 100644
index 6ab856b66f..0000000000
--- a/core/Log/Handler/StdErrHandler.php
+++ /dev/null
@@ -1,56 +0,0 @@
-<?php
-/**
- * Piwik - free/libre analytics platform
- *
- * @link http://piwik.org
- * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- */
-
-namespace Piwik\Log\Handler;
-
-use Monolog\Formatter\FormatterInterface;
-use Monolog\Handler\AbstractProcessingHandler;
-use Monolog\Logger;
-
-/**
- * Writes log to stderr.
- */
-class StdErrHandler extends AbstractProcessingHandler
-{
-    /**
-     * @var bool
-     */
-    private $isLoggingToStdOut;
-
-    public function __construct(FormatterInterface $formatter, $isLoggingToStdOut)
-    {
-        $this->isLoggingToStdOut = $isLoggingToStdOut;
-
-        // Log level is hardcoded for this one
-        $level = Logger::ERROR;
-
-        parent::__construct($level);
-
-        $this->setFormatter($formatter);
-    }
-
-    protected function write(array $record)
-    {
-        // Do not log on stderr during tests (prevent display of errors in CI output)
-        if (! defined('PIWIK_TEST_MODE')) {
-            $this->writeToStdErr($record['formatted']);
-        }
-
-        // This is the result of an old hack, I guess to force the error message to be displayed in case of errors
-        // TODO we should get rid of it somehow
-        if (! $this->isLoggingToStdOut) {
-            echo $record['formatted'];
-        }
-    }
-
-    private function writeToStdErr($message)
-    {
-        $fe = fopen('php://stderr', 'w');
-        fwrite($fe, $message);
-    }
-}
diff --git a/core/dispatch.php b/core/dispatch.php
index 86b810500a..d842b6a727 100644
--- a/core/dispatch.php
+++ b/core/dispatch.php
@@ -39,10 +39,6 @@ if (PIWIK_ENABLE_DISPATCH) {
             echo $response;
         }
     } catch (Exception $ex) {
-        $response = $controller->getErrorResponse($ex);
-
-        echo $response;
-
-        exit(1);
+        ExceptionHandler::dieWithHtmlErrorPage($ex);
     }
 }
\ No newline at end of file
diff --git a/tests/PHPUnit/Integration/LogTest.php b/tests/PHPUnit/Integration/LogTest.php
index d8f2e6cb3e..924b5cc0b7 100644
--- a/tests/PHPUnit/Integration/LogTest.php
+++ b/tests/PHPUnit/Integration/LogTest.php
@@ -24,7 +24,7 @@ require_once PIWIK_INCLUDE_PATH . '/tests/resources/TestPluginLogClass.php';
 
 /**
  * @group Core
- * @group Core_LogTest
+ * @group Log
  */
 class LogTest extends IntegrationTestCase
 {
@@ -33,49 +33,19 @@ class LogTest extends IntegrationTestCase
     const STRING_MESSAGE_FORMAT_SPRINTF = "[%s] %s";
 
     public static $expectedExceptionOutput = array(
-        'screen' => '<div style=\'word-wrap: break-word; border: 3px solid red; padding:4px; width:70%; background-color:#FFFF96;\'>
-        <strong>There is an error. Please report the message
-        and full backtrace in the <a href=\'?module=Proxy&action=redirect&url=http://forum.piwik.org\' target=\'_blank\'>Piwik forums</a> (please do a Search first as it might have been reported already!).</strong><br /><br/>
-        <em>dummy error message</em> in <strong>LogTest.php</strong> on line <strong>174</strong>
-<br /><br />Backtrace --&gt;<div style="font-family:Courier;font-size:10pt"><br />
-dummy backtrace</div></div>',
-        'file' => '[Piwik\Tests\Integration\LogTest] LogTest.php(174): dummy error message
+        'file' => '[Piwik\Tests\Integration\LogTest] LogTest.php(132): dummy error message
   dummy backtrace',
-        'database' => '[Piwik\Tests\Integration\LogTest] LogTest.php(174): dummy error message
+        'database' => '[Piwik\Tests\Integration\LogTest] LogTest.php(132): dummy error message
   dummy backtrace'
     );
 
     public static $expectedErrorOutput = array(
-        'screen' => '<div style=\'word-wrap: break-word; border: 3px solid red; padding:4px; width:70%; background-color:#FFFF96;\'>
-        <strong>There is an error. Please report the message
-        and full backtrace in the <a href=\'?module=Proxy&action=redirect&url=http://forum.piwik.org\' target=\'_blank\'>Piwik forums</a> (please do a Search first as it might have been reported already!).</strong><br /><br/>
-        <em>Unknown error (102) - dummy error string</em> in <strong>dummyerrorfile.php</strong> on line <strong>145</strong>
-<br /><br />Backtrace --&gt;<div style="font-family:Courier;font-size:10pt"><br />
-dummy backtrace</div></div>',
         'file' => '[Piwik\Tests\Integration\LogTest] dummyerrorfile.php(145): Unknown error (102) - dummy error string
   dummy backtrace',
         'database' => '[Piwik\Tests\Integration\LogTest] dummyerrorfile.php(145): Unknown error (102) - dummy error string
   dummy backtrace'
     );
 
-    private $screenOutput;
-
-    public static function setUpBeforeClass()
-    {
-        parent::setUpBeforeClass();
-
-        Error::setErrorHandler();
-        ExceptionHandler::setUp();
-    }
-
-    public static function tearDownAfterClass()
-    {
-        restore_error_handler();
-        restore_exception_handler();
-
-        parent::tearDownAfterClass();
-    }
-
     public function setUp()
     {
         parent::setUp();
@@ -110,7 +80,6 @@ dummy backtrace</div></div>',
     public function getBackendsToTest()
     {
         return array(
-            'screen'   => array('screen'),
             'file'     => array('file'),
             'database' => array('database'),
         );
@@ -123,10 +92,7 @@ dummy backtrace</div></div>',
     {
         Config::getInstance()->log['log_writers'] = array($backend);
 
-        ob_start();
         Log::warning(self::TESTMESSAGE);
-        $this->screenOutput = ob_get_contents();
-        ob_end_clean();
 
         $this->checkBackend($backend, self::TESTMESSAGE, $formatMessage = true, $tag = __CLASS__);
     }
@@ -138,10 +104,7 @@ dummy backtrace</div></div>',
     {
         Config::getInstance()->log['log_writers'] = array($backend);
 
-        ob_start();
         Log::warning(self::TESTMESSAGE, " subst ");
-        $this->screenOutput = ob_get_contents();
-        ob_end_clean();
 
         $this->checkBackend($backend, sprintf(self::TESTMESSAGE, " subst "), $formatMessage = true, $tag = __CLASS__);
     }
@@ -153,14 +116,10 @@ dummy backtrace</div></div>',
     {
         Config::getInstance()->log['log_writers'] = array($backend);
 
-        ob_start();
         $error = new \ErrorException("dummy error string", 0, 102, "dummyerrorfile.php", 145);
         Log::error($error);
-        $this->screenOutput = ob_get_contents();
-        ob_end_clean();
 
         $this->checkBackend($backend, self::$expectedErrorOutput[$backend], $formatMessage = false, $tag = __CLASS__);
-        $this->checkBackend('screen', self::$expectedErrorOutput['screen']); // errors should always written to the screen
     }
 
     /**
@@ -170,14 +129,10 @@ dummy backtrace</div></div>',
     {
         Config::getInstance()->log['log_writers'] = array($backend);
 
-        ob_start();
         $exception = new Exception("dummy error message");
         Log::error($exception);
-        $this->screenOutput = ob_get_contents();
-        ob_end_clean();
 
         $this->checkBackend($backend, self::$expectedExceptionOutput[$backend], $formatMessage = false, $tag = __CLASS__);
-        $this->checkBackend('screen', self::$expectedExceptionOutput['screen']); // errors should always written to the screen
     }
 
     /**
@@ -187,10 +142,7 @@ dummy backtrace</div></div>',
     {
         Config::getInstance()->log['log_writers'] = array($backend);
 
-        ob_start();
         TestLoggingUtility::doLog(self::TESTMESSAGE);
-        $this->screenOutput = ob_get_contents();
-        ob_end_clean();
 
         $this->checkBackend($backend, self::TESTMESSAGE, $formatMessage = true, $tag = 'TestPlugin');
     }
@@ -203,10 +155,7 @@ dummy backtrace</div></div>',
         Config::getInstance()->log['log_writers'] = array($backend);
         Config::getInstance()->log['log_level'] = 'ERROR';
 
-        ob_start();
         Log::info(self::TESTMESSAGE);
-        $this->screenOutput = ob_get_contents();
-        ob_end_clean();
 
         $this->checkNoMessagesLogged($backend);
     }
@@ -218,10 +167,7 @@ dummy backtrace</div></div>',
     {
         Config::getInstance()->log['log_writers'] = array($backend);
 
-        ob_start();
         TestLoggingUtility::doLog(" \n   ".self::TESTMESSAGE."\n\n\n   \n");
-        $this->screenOutput = ob_get_contents();
-        ob_end_clean();
 
         $this->checkBackend($backend, self::TESTMESSAGE, $formatMessage = true, $tag = 'TestPlugin');
     }
@@ -232,19 +178,7 @@ dummy backtrace</div></div>',
             $expectedMessage = sprintf(self::STRING_MESSAGE_FORMAT_SPRINTF, $tag, $expectedMessage);
         }
 
-        // remove version number from message
-        $this->screenOutput = str_replace(" (Piwik ". \Piwik\Version::VERSION.")", "", $this->screenOutput);
-
-        if ($backend == 'screen') {
-            if ($formatMessage
-                && !Common::isPhpCliMode()) {
-                $expectedMessage = '<pre>' . $expectedMessage . '</pre>';
-            }
-
-            $this->screenOutput = $this->removePathsFromBacktrace($this->screenOutput);
-
-            $this->assertEquals($expectedMessage . "\n", $this->screenOutput, "unexpected output: ".$this->screenOutput);
-        } else if ($backend == 'file') {
+        if ($backend == 'file') {
             $this->assertTrue(file_exists(self::getLogFileLocation()));
 
             $fileContents = file_get_contents(self::getLogFileLocation());
@@ -270,9 +204,7 @@ dummy backtrace</div></div>',
 
     private function checkNoMessagesLogged($backend)
     {
-        if ($backend == 'screen') {
-            $this->assertEmpty($this->screenOutput, "Output not empty: ".$this->screenOutput);
-        } else if ($backend == 'file') {
+        if ($backend == 'file') {
             $this->assertFalse(file_exists(self::getLogFileLocation()));
         } else if ($backend == 'database') {
             $this->assertEquals(0, Db::fetchOne("SELECT COUNT(*) FROM " . Common::prefixTable('logger_message')));
diff --git a/tests/PHPUnit/Unit/Log/Formatter/LineMessageFormatterTest.php b/tests/PHPUnit/Unit/Log/Formatter/LineMessageFormatterTest.php
index 2276a2c4eb..9b9aac78b1 100644
--- a/tests/PHPUnit/Unit/Log/Formatter/LineMessageFormatterTest.php
+++ b/tests/PHPUnit/Unit/Log/Formatter/LineMessageFormatterTest.php
@@ -11,6 +11,11 @@ namespace Piwik\Tests\Unit\Log\Formatter;
 use DateTime;
 use Piwik\Log\Formatter\LineMessageFormatter;
 
+/**
+ * @group Core
+ * @group Log
+ * @covers \Piwik\Log\Formatter\LineMessageFormatter
+ */
 class LineMessageFormatterTest extends \PHPUnit_Framework_TestCase
 {
     /**
diff --git a/tests/PHPUnit/Unit/Log/Processor/ClassNameProcessorTest.php b/tests/PHPUnit/Unit/Log/Processor/ClassNameProcessorTest.php
index 42fa7c81fd..2e002196e2 100644
--- a/tests/PHPUnit/Unit/Log/Processor/ClassNameProcessorTest.php
+++ b/tests/PHPUnit/Unit/Log/Processor/ClassNameProcessorTest.php
@@ -12,6 +12,7 @@ use Piwik\Log\Processor\ClassNameProcessor;
 
 /**
  * @group Core
+ * @group Log
  * @covers \Piwik\Log\Processor\ClassNameProcessor
  */
 class ClassNameProcessorTest extends \PHPUnit_Framework_TestCase
diff --git a/tests/PHPUnit/Unit/Log/Processor/ExceptionToTextProcessorTest.php b/tests/PHPUnit/Unit/Log/Processor/ExceptionToTextProcessorTest.php
index 398229d98d..54cff2ae37 100644
--- a/tests/PHPUnit/Unit/Log/Processor/ExceptionToTextProcessorTest.php
+++ b/tests/PHPUnit/Unit/Log/Processor/ExceptionToTextProcessorTest.php
@@ -12,6 +12,8 @@ use Piwik\Log;
 use Piwik\Log\Processor\ExceptionToTextProcessor;
 
 /**
+ * @group Core
+ * @group Log
  * @covers \Piwik\Log\Processor\ExceptionToTextProcessor
  */
 class ExceptionToTextProcessorTest extends \PHPUnit_Framework_TestCase
@@ -46,7 +48,7 @@ class ExceptionToTextProcessorTest extends \PHPUnit_Framework_TestCase
         $result = $processor($record);
 
         $expected = array(
-            'message' => __FILE__ . "(39): Hello world\n[stack trace]",
+            'message' => __FILE__ . "(41): Hello world\n[stack trace]",
             'context' => array(
                 'exception' => $exception,
             ),
diff --git a/tests/PHPUnit/Unit/Log/Processor/RequestIdProcessorTest.php b/tests/PHPUnit/Unit/Log/Processor/RequestIdProcessorTest.php
index 8c12528572..b9c809b6e6 100644
--- a/tests/PHPUnit/Unit/Log/Processor/RequestIdProcessorTest.php
+++ b/tests/PHPUnit/Unit/Log/Processor/RequestIdProcessorTest.php
@@ -13,6 +13,7 @@ use Piwik\Log\Processor\RequestIdProcessor;
 
 /**
  * @group Core
+ * @group Log
  * @covers \Piwik\Log\Processor\RequestIdProcessor
  */
 class RequestIdProcessorTest extends \PHPUnit_Framework_TestCase
diff --git a/tests/PHPUnit/Unit/Log/Processor/SprintfProcessorTest.php b/tests/PHPUnit/Unit/Log/Processor/SprintfProcessorTest.php
index 69f102789e..7966b165de 100644
--- a/tests/PHPUnit/Unit/Log/Processor/SprintfProcessorTest.php
+++ b/tests/PHPUnit/Unit/Log/Processor/SprintfProcessorTest.php
@@ -12,6 +12,7 @@ use Piwik\Log\Processor\SprintfProcessor;
 
 /**
  * @group Core
+ * @group Log
  * @covers \Piwik\Log\Processor\SprintfProcessor
  */
 class SprintfProcessorTest extends \PHPUnit_Framework_TestCase