Explains the Arquillian configuration in the README.md file

An explanation of how Arquillian tests are configured and how to run the
Arquillian tests in the Eclipse project has been added to the root
README.md.

README.md

@@ -51,6 +51,65 @@ unit testing in this layer, as we don't want to mock the `EntityManager`.
 In this layer we will use some workarounds to set the desired role and principal
 in the tests.
 
+### How to run tests with Arquillian?
+This project is configured to use two Maven profiles:
+* `wildfly-embedded-h2`: This profile uses Wildfly in embedded mode with the H2
+`ExampleDS` database that is included by default in this Java EE server (it has
+the JNDI name `java:jboss/datasources/ExampleDS`).
+* `wildfly-embedded-mysql`: Same as before, but it uses a MySQL datasource with
+the JNDI name `java:jboss/datasources/xcs`.
+
+In both profiles, the Wildfly server is downloaded automatically using the
+`maven-dependency-plugin`, that extracts it in the `target/wildfly-<version>`
+folder (`target/wildfly-8.2.1.Final` currently). In the MySQL profile, the MySQL
+driver is also downloaded using this plugin and added to the
+`target/wildfly-<version>/standalone/deployments` folder, to make it available
+in the Wildfly server.
+
+For each profile, Maven is configured to use the files stored in
+`src/test/resources-<profile name>` as resources when running tests, in addition
+to the stored in the `src/test/resources` folder, as usual. Inside this folder,
+the projects using Arquillian must include a `standalone.xml` file, that will be
+replace the default `standalone.xml` file of the Wildfly server. This is
+specially useful to configure the security constraints. The MySQL resources
+folder must also include a `mysql-ds.xml` file, with the MySQL datasource
+configuration that will be added to the Wildfly server.
+
+Therefore, when running Maven tests (e.g. `mvn test`), they will run without any
+external requirement.
+
+#### Arquillian tests in Eclipse
+To run Arquillian tests in Eclipse (or in any non-Maven enviroment) a further
+step is needed. You must configure the following system properties:
+* `java.util.logging.manager`: The logger to be used by the standard Java
+logger. Commonly, the value `org.jboss.logmanager.LogManager` is used.
+* `wildfly.version`: The version of the Wildfly server stored in `target`.
+The current version is `8.2.1.Final`.
+
+In Eclipse, this system properties can be added to the run configuration in the
+`VM arguments` field of the `Arguments` tab. For example, the following
+configuration will work for the current configuration:
+```
+-Dwildfly.version=8.2.1.Final
+-Djava.util.logging.manager=org.jboss.logmanager.LogManager
+```
+This configuration will run with the **h2** database. If you wish to run the
+tests with the **MySQL** database, you have to add to additional system
+configuration:
+* `mysql.version`: The version of the MySQL driver (currently, `5.1.21`). This
+version is used by the `mysql-ds.xml` configuration files.
+* `arquillian.launch`: This system property is used to change the profile used
+by Arquillian. It should be `wildfly-embedded-mysql` to use the MySQL profile.
+
+Therefore, the `VM arguments` configuration for running the tests in Eclipse
+using the MySQL database is:
+```
+-Dwildfly.version=8.2.1.Final
+-Djava.util.logging.manager=org.jboss.logmanager.LogManager
+-Dmysql.version=5.1.21
+-Darquillian.launch=wildfly-embedded-mysql
+```
+
 ## Sample 3: Testing with test doubles
 Using EasyMock, we will mock the EJBs to test the REST classes isolated from the
 underlying layer.