Citrus comes with a powerful set of actions built-in, covering a wide range of helpful SOA integration testing aspects like sending and receiving messages, database access, Java and Groovy scripting support or dealing with exceptions. For a full list of provided standard actions see the reference documentation. But each project and especially each system-under-test (SUT) comes along with its own specifics and characteristics, so chances are high that during a project the need for an extension of the built-in citrus actions will arise. This tutorial shall show you how easy and handsome it is to provide your own custom actions and reuse them inside your citrus integration tests.
Let’s quickly refresh our memory how citrus actions are used in a test case:
As you’ll notice (or already know) actions are written in a DSL-like syntax. But under the hood they end up as Spring beans - so using standard Spring mechanisms for extending citrus with your own custom actions will work like a charm. Let’s explore a first simple way to introduce a custom action into your testing project.
Using the generic action element
This approach is almost a no-brainer, but offers less flexibility as we will see later on. Let’s imagine a simplistic scenario: your SUT outputs a lot of file traffic during the tests, so that we need a simple way to clean up the mess in a specific directory right after a test run. We also put away the fact that this could be as well realized by using groovy or Java actions and decide to use a custom action instead.
The first step is to create our own action class which extends com.consol.citrus.actions.AbstractTestAction:
If you want to avoid inheritance here you could as well implement the interface com.consol.citrus.TestAction instead. The property directory is declared as field with appropriate getters and setters so that a value can be injected by the container.
Having your test action class ready, change to citrus-config.xml and make it available as Spring bean there:
Note that the directory value is injected here during declaration of the bean, a drawback we will address in a second. So for now, your first custom action is ready to be used in citrus tests using the generic action element provided by citrus:
Run your test project and enjoy your first custom action being executed. Easy so far, but as stated earlier, our custom action lacks some kind of configurability. If your SUT spammed 10 directories with files, you would have to declare one bean for each directory, not an optimal solution. So let’s head on for a more generic approach using Spring’s extensible XML authoring feature.
Using Spring’s schema-based extensions
Since version 2.0, Spring provides a mechanism to define your own bean definition schemas and wire them into the Spring container. We will use this mechanism to define our own custom action schema, describing XML action elements which can then be used in citrus tests. It is much easier than it sounds, so let’s get started. The functionality of our action bean stays the same, so just copy it and name it GenericCleanupDirAction inside the same package. Our aim is to be able to define actions in our tests like this:
To achieve this, we define our custom namespace (http://www.citrusframework.org/schema/jza/custom/actions) together with an XSD schema for our action declaration:
Important aspects are the declaration of the namespace we are using and the usage of Spring’s beans namespace for the XSD extension mechanism to add an id attribute to our action element (as an alternative, we could simply add it ourselves). Place the XSD into a package of your source tree (I used com.consol.jza.citrus.tutorial.schema in this example) and head on.
Next, we have to write two simple classes to tell Spring how to handle the bean definitions of our newly created namespace. At first, we have to provide a NamespaceHandler for our new namespace, registering a BeanDefinitionParser for our XML element:
We tell Spring to pass our top-level action element to our own parser implementation. The code for our custom BeanDefinitionParser is even simpler:
We select the most simple form by choosing to extend AbstractSimpleBeanDefinitionParser, only providing the bean class which shall be generated - the mapping (and injection) of XSD attributes to properties is performed by Spring in this case. Of course parsing can be extended for more complex (nested) elements, just ase a AbstractSingleBeanDefinitionParser instead and overwrite the doParse() method.
Now that all our coding is done, one final step has to be performed. We have to make Spring XML parsing infrastructure aware our new schema. To achieve this, we have to register our XSD file and the namespace handler in two special purpose properties files which have to reside in the META-INF directory of your testing jar file. Spring will detect these and automatically pick them up as extension. At first, we declare our handler inside META-INF/spring.handlers:
The left side is our own namespace (with escaped ‘:’) which gets assigned the package path to our custom handler implementation on the right. Having our handler registered, we notify Spring about the existence of our custom schema by adding META-INF/spring.schemas with the following content:
This entry defines a mapping of XML schema locations (which we will define right in a moment when using our new action namespace in our citrus tests) to the physical location of our custom XSD on the classpath.
So now everything is in place: we have coded our own namespace handler and bean parser, defined our custom action schema and namespace and registered all of it to Spring’s XML extensible authoring mechanism. Time to bring the harvest in and use our custom action in citrus tests as desired:
Note the declaration of our new namespace as ‘my’ and don’t forget to declare the mapping to the schemalocation as well. It will save you lots of curses and hours of debugging Spring - I’m speaking from experience here. ;)
That’s it for the custom actions tutorial. We looked at two ways to create custom citrus actions inside your test projects. Using the generic citrus action element is a very easy and quick way to add your custom coded actions to a test project. Using the XML extensible authoring mechanism provides you with full control and improved reusability through parameterization in XML. Whichever approach you choose, we hope you enjoy extending citrus with custom actions as we do.