Reverting removal of lock tests paragraph; minor fixes

tests/README.markdown

@@ -9,16 +9,34 @@ To execute the Doctrine2 testsuite, you just need to execute this simple steps:
 
  All this is (normally) done with:
 
-```
-git clone [email protected]:doctrine/doctrine2.git
-cd doctrine2
-composer install
-./vendor/bin/phpunit
-```
+    git clone [email protected]:doctrine/doctrine2.git
+    cd doctrine2
+    composer install
+    ./vendor/bin/phpunit
 
 ## Pre-requisites
 Doctrine2 works on many database vendors; the tests can detect the presence of installed vendors, but you need at least one of those; the easier to install is SQLite.
 
-If you're using a Debian-derivative Linux distribution, you can install SQLite with:
+If you're using Debian, or a Debian-derivate Linux distribution (like Ubuntu), you can install SQLite with:
 
     sudo apt-get install sqlite
+
+## Testing Lock-Support
+
+The Lock support in Doctrine 2 is tested using Gearman, which allows to run concurrent tasks in parallel.
+Install Gearman with PHP as follows:
+
+1. Go to http://www.gearman.org and download the latest Gearman Server
+2. Compile it and then call ldconfig
+3. Start it up "gearmand -vvvv"
+4. Install pecl/gearman by calling "gearman-beta"
+
+You can then go into `tests/` and start up two workers:
+
+    php Doctrine/Tests/ORM/Functional/Locking/LockAgentWorker.php
+
+Then run the locking test-suite:
+
+    phpunit --configuration <myconfig.xml> Doctrine/Tests/ORM/Functional/Locking/GearmanLockTest.php
+
+This can run considerable time, because it is using sleep() to test for the timing ranges of locks.