Citrus

Spring 5, Cucumber 3 and support for Apache Kafka. These are the big three of this release and together with bug fixes and some smaller features, we call it Citrus 2.8.0.

Citrus aims to strongly support you in simulating interface partners across different messaging transports. You can easily produce and consume messages with a wide range of protocols like HTTP, JMS, TCP/IP, FTP, SMTP and more. The framework is able to both act as a client and server. In each communication step Citrus is able to validate message contents towards syntax and semantics.

In addition to that the Citrus offers a wide range of test actions to take control of the process flow during a test (e.g. iterations, system availability checks, database connectivity, parallelism, delaying, error simulation, scripting and many more).

The basic goal in Citrus test cases is to describe a whole use case scenario including several interface partners that exchange many messages with each other. The composition of complex message flows in a single test case with several test steps is one of the major features in Citrus.

The test case description is either done in XML or Java and can be executed multiple times as automated integration test. With JUnit and TestNG integration Citrus can easily be integrated into your build lifecycle process. During a test Citrus simulates all surrounding interface partners (client or server) without any coding effort. With easy definition of expected message content (header and payload) for XML, CSV, SOAP, JSON or plaintext messages Citrus is able to validate the incoming data towards syntax and semantics.

If you are in charge of an enterprise application in a message based solution with message interfaces to other software components you should use Citrus. In case your project interacts with other software over different messaging transports and in case you need to simulate these interface partners on client or server side you should use Citrus. In case you need to continuously check the software stability not only on a unit testing basis but also in an end-to-end integration scenario you should use Citrus. Bug fixing, release or regression testing is very easy with Citrus. In case you are struggling with code stability and feel uncomfortable regarding your next software release you should definitely use Citrus.

This test set up is typical for a Citrus use case. In such a test scenario we have a system under test (SUT) with several message interfaces to other applications like you would have with an enterprise service bus for instance. A client application invokes services on the SUT application. The SUT is linked to several backend applications over various messaging transports (here SOAP, JMS, and Http). Interim message notifications and final responses are sent back to the client application. This generates a bunch of messages that are exchanged throughout the applications involved.

In the automated integration test Citrus needs to send and receive those messages over different transports. Citrus takes care of all interface partners (ClientApplication, Backend1, Backend2, Backend3) and simulates their behavior by sending proper response messages in order to keep the message flow alive.

Each communication step comes with message validation and comparison against an expected message template (e.g. XML or JSON data). Besides messaging actions Citrus is also able to perform arbitrary other test actions. Citrus is able to perform a database query between requests as an example.

The Citrus test case runs fully automated as a Java application. In fact a Citrus test case is nothing but a JUnit or TestNG test case. Step by step the whole use case scenario is performed like in a real production environment. The Citrus test is repeatable and is included into the software build process (e.g. using Maven or ANT) like a normal unit test case would do. This gives you fully automated integration tests to ensure interface stability.

The following reference guide walks through all Citrus capabilities and shows how to set up a great integration test with Citrus.

Citrus uses Maven internally as a project build tool and provides extended support for Maven projects. Maven will ease up your life as it manages project dependencies and provides extended build life cycles and conventions for compiling, testing, packaging and installing your Java project. Therefore it is recommended to use the Citrus Maven project setup. In case you already use Maven it is most suitable for you to include Citrus as a test-scoped dependency.

As Maven handles all project dependencies automatically you do not need to download any Citrus project artifacts in advance. If you are new to Maven please refer to the official Maven documentation to find out how to set up a Maven project.

As Citrus tests are nothing but normal JUnit or TestNG tests the integration to Gradle as build tool is as easy as adding the source files to a folder in your project. With the Gradle task execution for integration tests you are able to execute the Citrus tests like you would do with normal unit tests.

Ant is a very popular way to compile, test, package and execute Java projects. The Apache project has effectively become a standard in building Java projects. You can run Citrus test cases with Ant as Citrus is nothing but a Java application. This section describes the steps to setup a proper Citrus Ant project.

Put simply, a Citrus test case is nothing but a simple Spring XML configuration file. The Spring framework has become a state of the art development framework for enterprise Java applications. As you work with Citrus you will also learn how to use the Spring Ioc (Inversion of control) container and the concepts of dependency injection. So let us have a look at the pure Spring XML configuration syntax first. You are free to write fully compatible test cases for the Citrus framework just using this syntax.

Citrus can execute these Spring bean definitions as normal test cases - no problem, but the pure Spring XML syntax is very verbose and probably not the best way to describe a test case in Citrus. In particular you have to know a lot of Citrus internals such as Java class names and property names. In addition to that as test scenarios get more complex the test cases grow in size. So we need a more effective and comfortable way of writing tests. Therefore Citrus provides a custom XML schema definition for writing test cases which is much more adequate for our testing purpose.

The custom XML schema aims to reach the convenience of domain specific languages (DSL). Let us have a look at the Citrus test describing XML language by introducing a first very simple test case definition:

We do need the `<spring:beans>` root element as the XML file is read by the Spring IoC container. Inside this root element the Citrus specific namespace definitions take place.

The test case itself gets a mandatory name that must be unique throughout all test cases in a project. You will receive errors when using duplicate test names. The test name has to follow the common Java naming conventions and rules for Java classes. This means names must not contain any whitespace characters but characters like '-', '.', '' are supported. For example, _TestFeature_1 is valid but Test Feature 1 is not as it contains whitespace characters like spaces.

Now that we have an XML definition that describes the steps of our test we need a Java executable for the test. The Java executable is needed for the framework in order to run the test. See the following sample Java class that represents a simple Citrus Java test:

The sample above is a Java class that represents a valid Citrus Java executable. The Java class has no programming logic as we use a XML test case here. The Java class can also be generated using the Citrus Maven plugin. The Java class extends from basic superclass AbstractTestNGCitrusTest and therefore uses TestNG as unit test framework. Citrus also supports JUnit as unit test framework. Read more about this in run-with-testngand run-with-junit.

Up to now it is important to understand that Citrus always needs a Java executable test class. In case we use the XML test representation the Java part is generic, can be generated and contains no programming logic. The XML test defines all steps and is our primary test case definition.

Before we go into more details on the attributes and actions that take place within a test case we just have a look at how to write test cases with pure Java code. Citrus works with Java and uses the well known JUnit and TestNG framework benefits that you may be used to as a tester. Many users may prefer to write Java code instead of the verbose XML syntax. Therefore you have another possibility for writing Citrus tests in pure Java.

When using the Citrus Java DSL we need to include a special Maven dependency module to our project that provides the needed API.

Citrus in general differences between two ways of test cases in Java. These are test-designers and test-runners that we deal with each in the next two sections.

The first way of defining a Citrus test in Java is the test-designer . The Java DSL for a test designer works similar to the XML approach. The whole test case is built with all test actions first. Then the whole test case is executed as a whole Citrus test. This is how to define a Citrus test with designer Java DSL methods:

Citrus provides a base Java class com.consol.citrus.dsl.testng.TestNGCitrusTestDesigner that provides all capabilities for you in form of builder pattern methods. Just use the @CitrusTest annotation on top of the test method. Citrus will use the method name as the test name by default. As you can see in the example above you can also customize the test name within the @CitrusTest annotation. The test method builds all test actions using the test builder pattern. The defined test actions will then be called later on during test runtime.

The design time runtime difference in test-designer is really important to be understood. You can mix the Citrus Java DSL execution with other Java code with certain limitations. We will explain this later on when introducing the test-runner .

This is the basic test Java class pattern used in Citrus. You as a tester with development background can easily extend this pattern for customized logic. Again if you are coming without coding experience do not worry this Java code is optional. You can do exactly the same with the XML syntax only as shown before. The test designer Java DSL is much more powerful though as you can use the full Java programming language with class inheritance and method delegation.

We have mentioned that the test-designer will build the complete test case in design time with all actions first before execution of the whole test case takes place at runtime of the test. This approach has the advantage that Citrus knows all test actions in a test before execution. On the other hand you are limited in mixing Java DSL method calls and normal Java code. The following example should clarify things a little bit.

In this example test case above we use an instance of a custom LoggingService and call some operation log() in the middle of our Java DSL test. Now developers might expect the logging service call to be done in the middle of the Java Citrus test case but if we have a look at the logging output of the test we get a total different result:

So if we analyse the actual logging output we see that the logging service was called even before the Citrus test case did start its action. This is the result of test-designer building up the whole test case first. The designer collects all test actions first in internal memory cache and the executes the whole test case. So the custom service call on the LoggingService is not part of the Citrus Java DSL test and therefore is executed immediately at design time.

We can fix this with the following test-designer code:

Now we placed the loggingService call inside a custom TestAction implementation and therefore this piece of code is part of the Citrus Java DSL and following from that part of the Citrus test execution. Now with that fix we get the expected logging output:

Now this is not easy to understand and people did struggle with this separation of designtime and runtime of a Citrus Java DSL test. This is why we have implemented a new Java DSL base class called test-runner that we deal with in the next section. Before we continue we have to mention that the test-designer approach does also work for JUnit. Although we have only seen TestNG sample code in this section everything is working exactly the same way with JUnit framework. Just use the base class com.consol.citrus.dsl.junit.JUnit4CitrusTestDesigner instead.

The new test runner concept solves the issues that may come along when working with the test designer. We have already seen a simple example where the test designer requires strict separation of designtime and runtime. The test runner implementation executes each test action immediately. This changes the prerequisites in such that the test action Java DSL method calls can be mixed with usual Java code statements. The the example that we have seen before in a test runner implementation:

With the new test runner implementation as base class we are able to mix Java DSL method calls and normal Java code statement in our test in an unlimited way. This example above will also create the expected logging output as all Java DSL method calls are executed immediately.

In contrary to the test designer the test runner implementation will not build the complete test case before execution. Each test action is executed immediately as it is called with Java DSL builder methods. This creates a more natural way of coding test cases as you are also able to use iterations, try catch blocks, finally sections and so on.

In the examples here TestNG was used as unit framework. Of course the exact same approach can also apply to JUnit framework. Just use the base class com.consol.citrus.dsl.junit.JUnit4CitrusTestRunner instead. Feel free to choose the base class for test-designer or test-runner as you like. You can also mix those two approaches in your project. Citrus is able to handle both ways of Java DSL code in a project.

In the previous sections we have seen the different approaches for test designer and runner implementations. Up to now the decision which implementation to use was made by extending one of the base classes:

These four classes represent the different designer and runner implementations for TestNG or JUnit. Now Citrus also provides a resource injection mechanism for both designer and runner implementations. The classes using this feature are:

So what is the deal with that? It is simple when looking at a first example using resource injection:

The designer or runner instance is injected as Citrus resource to the test method as parameter. This way we can mix designer and runner in a single test. But this is not the real motivation for the resource injection. The clear advantage of this approach with injected designer and runner instances is support for multi threading. In case you want to execute the Citrus tests in parallel using multiple threads you need to use this approach. This is because the usual designer and runner base classes are not thread safe. This JUnit4CitrusTest base class is because the resources injected are not kept as state in the base class.

This is our first Citrus resource injection use case. The framework is able to inject other resources, too. Find out more about this in the next sections.

When running a test case in Citrus we make use of basic framework components and capabilities. One of these capabilities is to use test variables, functions and validation matchers. Up to this point we have not learned about these things. They will be described in the upcoming chapters and sections in more detail. Right now I want to talk about resource injection in Citrus.

All these feature mentioned above are bound to some important Citrus component: the Citrus test context. The test context holds all variables and is able to resolve functions and matchers. In general you as a tester will not need explicit access to this component as the framework is working with it behind the scenes. In case you need some access for advanced operations with the framework Citrus provides a resource injection. Lets have a look at this so things are getting more clear.

As you can see we have added a method parameter of type com.consol.citrus.context.TestContext to the test method. The annotation @CitrusResource tells Citrus to inject this parameter with the according instance of the object for this test. Now we have easy access to the context and all its capabilities such as variable management.

Of course the same approach works with TestNG, too. As TestNG also provides resource injection mechanisms we have to make sure that the different resource injection approaches do not interfere with each other. So we tell TestNG to not inject this parameter by declaring it as @Optional for TestNG. In addition to that we need to introduce the parameter to TestNG with the @Parameters annotation. Otherwise TestNG would complain about not knowing this parameter. The final test method with Citrus resource injection looks like follows:

Some more annotations needed but the result is the same. We have access to the Citrus test context. Of course you can combine the resource injection for different Citrus components. Just add more some @CitrusResource annotated method parameters to the test method.

When using the Java DSL the concept of behaviors is a good way to reuse test action blocks. By putting test actions to a test behavior we can instantiate and apply the behavior to different test cases multiple times. The mechanism is explained best when having a simple sample:

The listing above shows two test behaviors that add very specific test actions and test variables to the test case. As you can see the test behavior is able to use the same Java DSL action methods as a normal test case would do. Inside the apply method block we define the behaviors test logic. Now once this is done we can use the behaviors in a test case like this:

The behavior is applied to the test case by calling the applyBehavior method. As a result the behavior is called adding its logic at this point of the test execution. The same behavior can now be called in multiple test cases so we have a reusable set of test actions.

In the test examples that we have seen so far you may have noticed that a tester can give a detailed test description. The test case description clarifies the testing purpose and perspectives. The description should give a short introduction to the intended use case scenario that will be tested. The user should get a first impression what the test case is all about as well as special information to understand the test scenario. You can use free text in your test description no limit to the number of characters. But be aware of the XML validation rules of well formed XML when using the XML test syntax (e.g. special character escaping, use of CDATA sections may be required)

Now we get close to the main part of writing an integration test. A Citrus test case defines a sequence of actions that will take place during the test. Actions by default are executed sequentially in the same order as they are defined in the test case definition.

All actions have individual names and properties that define the respective behavior. Citrus offers a wide range of test actions from scratch, but you are also able to write your own test actions in Java or Groovy and execute them during a test. actions gives you a brief description of all available actions that can be part of a test case execution.

The actions are combined in free sequence to each other so that the tester is able to declare a special action chain inside the test. These actions can be sending or receiving messages, delaying the test, validating the database and so on. Step-by-step the test proceeds through the action chain. In case one single action fails by reason the whole test case is red and declared not successful.

Java developers might be familiar with the concept of doing something in the finally code section. The finally section contains a list of test actions that will be executed guaranteed at the very end of the test case even if errors did occur during the execution before. This is the right place to tidy up things that were previously created by the test like cleaning up the database for instance. The finally section is described in more detail in finally-section. However here is the basic syntax inside a test.

The user can provide some additional information about the test case. The meta-info section at the very beginning of the test case holds information like author, status or creation date. In detail the meta information is specified like this:

The status allows following values: DRAFT, READY_FOR_REVIEW, DISABLED, FINAL. The meta-data information to a test is quite important to give the reader a first information about the test. It is also possible to generate test documentation using this meta-data information. The built-in Citrus documentation generates HTML or Excel documents that list all tests with their metadata information and description.

Now you know the possibilities how to write Citrus test cases in XML or Java. Please choose whatever code language type you want (Java, XML, Spring bean syntax) in order to write Citrus test cases. Developers may choose Java, testers without coding experience may run best with the XML syntax. We are constantly working on even more test writing language support such as Groovy, Scala, Xtext, and so on. In general you can mix the different language types just as you like within your Citrus project which gives you the best of flexibility.

The last section told us to use variables as they are very useful and extend the maintainability of test cases. Now that every test case defines local variables you can also define global variables. The global variables are valid in all tests by default. This is a good opportunity to declare constant values for all tests. As these variables are global we need to add those to the basic Spring application context file. The following example demonstrates how to add global variables in Citrus:

We add the Spring bean component to the application context file. The component receives a list of name-value variable elements. You can reference the global variables in your test cases as usual.

Another possibility to set global variables is to load those from external property files. This may give you more powerful global variables with user specific properties for instance. See how to load property files as global variables in this example:

We have just added a file path reference to the global variables component. Citrus loads the property file content as global test variables. You can mix property file and name-value pair variable definitions in the global variables component.

When using th XML test case DSL we can not have XML variable values out of the box. This would interfere with the XML DSL elements defined in the Citrus testcase XSD schema. You can use CDATA sections within the variable value element in order to do this though.

That is how you can use XML variable values in the XML DSL. In the Java DSL we do not have these problems.

You can also use a script to create variable values. This is extremely handy when you have very complex variable values. Just code a small Groovy script for instance in order to define the variable value. A small sample should give you the idea how that works:

We use the script code right inside the variable value definition. The value of the variable is the result of the last operation performed within the script. For longer script code the use of `<![CDATA[ ]]>` sections is recommended.

Citrus uses the javax ScriptEngine mechanism in order to evaluate the script code. By default Groovy is supported in any Citrus project. So you can add additional ScriptEngine implementations to your project and support other script types, too.

The test variables expression syntax "${variable-name}" is preserved to evaluate to a test variable within the current test context. However the same syntax may be part of a message content as is. So you need to somehow escape the syntax from beeing interpreted as test variable syntax. You can do this by using the variable expression escaping // character sequence wrapping the actual variable name like this

The escaped expression ${//escaped//} above will result in the string ${escaped} where escaped is not treated as a test variable name but as a normal string in the message payload. This way you are able to have the same variable syntax in a message content without interfering with the Citrus variable expression syntax. As a result Citrus will not complain about not finding the test variable escaped in the current context. The variable syntax escaping characters // are automatically removed when the expression is processed by Citrus. So we will get the following result after processing.

TestNG stands for next generation testing and has had a great influence in adding Java annotations to the unit test community. Citrus is able to generate TestNG Java classes that are executable as test cases. See the following standard template that Citrus will generate when having new test cases:

If you are familiar with TestNG you will see that the generated Java class is nothing but a normal TestNG test class. We just extend a basic Citrus TestNG class which enables the Citrus test execution features for us. Besides that we have a usual TestNG @Test annotation placed on our class so all methods inside the class will be executed as separate test case.

The good news is that we can still use the fantastic TestNG features in our test class. You can think of parallel test execution, test groups, setup and tear down operations and so on. Just to give an example we can simply add a test group to our test like this:

@Test(groups = {"long-running"})

For more information on TestNG please visit the official homepage, where you find a complete reference documentation.

You might have noticed that the example above loads test cases from XML. This is why we are using the @CitrusXmlTest annotation. Again this approach is for people that want to write no Java code. The test logic is then provided in the XML test definition. We discuss XML tests in Citrus in more detail in run-xml-tests. Next lets have a look at a TestNG Java DSL test.

When writing tests in pure Java we have pretty much the exact same logic that applies to executing Citrus test cases. The Citrus test extends from a TestNG base class and uses the normal @Test annotations on method or class level. Here is a short sample TestNG Java class for this:

You see the class is quite similar to the XML test variation. Now we extend a Citrus test designer class which enables the Java DSL features in addition to the TestNG test execution for us. The basic @Test annotation for TestNG has not changed. We still have a usual TestNG class with the possibility of several methods each representing a separate unit test.

Now what has changed is the @CitrusTest annotation. Now the Citrus test logic is placed directly as the method body with using the Java domain specific language features. The XML Citrus test part is not necessary anymore. If you are wondering about the designer super class and the Java DSL methods for adding the test logic to your test please be patient we will learn more about the Java DSL features in this reference guide later on.

Up to now we just concentrate on the TestNG integration that is quite easy isn’t it.

TestNG as a framework comes with lots of great features such as data providers. Data providers execute a test case several times. Each test execution gets a specific parameter value. With Citrus you can use those data provider parameters inside the test as variables. See the next listing on how to use TestNG data providers in Citrus:

Above test case method is annotated with TestNG data provider called messageDataProvider . In the same class you can write the data provider that returns a list of parameter values. TestNG will execute the test case several times according to the provided parameter list. Each execution is shipped with the respective parameter value. According to the @CitrusParameter annotation the test will have a test variable called message that is accessible as usual.

JUnit5 is the new major version of the famous unit testing framework. The JUnit platform provides extension points for other frameworks to integrate with the unit testing execution. Citrus uses these extensions in order to enable Citrus related dependency injection and parameter resolving.

You can use the Citrus JUnit5 extension on your unit test as follows:

The class above is using the JUnit5 @Test annotation as a normal unit test would do. In addition to that we extend with the CitrusBaseExtension. This enables us to use the @CitrusXmlTest annotation on the test method which automatically loads the XML test case file for execution.

In case you want to use the Citrus Java DSL for writing the test logic you can use the following setup:

The Java DSL test case is using the CitrusExtension to extend the JUnit5 test with Citrus functionality. After doing that we can use @CitrusResource annotated method parameters that inject the test designer. The designer is the entrance to the Java fluent API provided by Citrus. Of course you can also inject the test runner fluent API.

You can also use @TestContext parameter injection in order to get access to the current test context used by Citrus. Also you can inject Citrus endpoints via @CitrusEndpoint annotated field injection in your test class. This enabled you to inject endpoint components that are defined in the Citrus Spring application context configuration.

JUnit is a very popular unit test framework for Java applications widely accepted and widely supported by many tools. In general Citrus supports both JUnit and TestNG as test execution frameworks. Although the TestNG customization features are slightly more powerful than those offered by JUnit you as a Citrus user should be able to use the framework of your choice. The complete support for executing test cases with package scans and multiple annotated methods is given for both frameworks. If you choose junit as execution framework Citrus generates a Java file that looks like this:

JUnit and TestNG as frameworks reveal slight differences, but the idea is the same. We extend a base JUnit Citrus test class and have one to many test methods that load the XML Citrus test cases for execution. As you can see the test class can hold several annotated test methods that get executed as JUnit tests. The fine thing here is that we are still able to use all JUnit features such as before/after test actions or enable/disable tests.

The Java JUnit classes are simply responsible for loading and executing the Citrus test cases. Citrus takes care on loading the XML test as a file system resource and to set up the Spring application context. The test is executed and success/failure state is reported exactly like a usual JUnit unit test would do. This also means that you can execute this Citrus JUnit class like every other JUnit test, especially out of any Java IDE, with Maven, with ANT and so on. This means that you can easily include the Citrus test execution into you software building lifecycle and continuous build.

The first example seen here is using @CitrusXmlTest annotation in order to load a XML file as test. The Java part is then just an empty envelope for executing the test with JUnit. This approach is for those of you that are not familiar with Java at all. You can find more information on loading XML files as Citrus tests in run-xml-tests. Secondly of course we also have the possibility to use the Citrus Java DSL with JUnit. See the following example on how this looks like:

The Java DSL test case looks quite familiar as we also use the JUnit4 @Test annotation in order to mark our test for unit test execution. In addition to that we add a @CitrusTest annotation and extend from a basic JUnit4 Citrus test designer which enables the Java domain specific language features. The Citrus test logic goes directly to the method block. There is no need for a XML test file anymore.

As you can see the @CitrusTest annotation supports multiple test methods in one single class. Each test is prepared and executed separately just as you know it from JUnit. You can define an explicit Citrus test name that is used in Citrus test reports. If no explicit test name is given the test method name will be used as a test name.

If you need to know more details about the test designer and on how to use the Citrus Java DSL just continue with this reference guide. We will describe the capabilities in detail later on.

Now we also use the @CitrusXmlTest annotation in the Java class. This annotation makes Citrus search for a XML file that represents the Citrus test within your classpath. Later on we will also discuss another Citrus annotation (@CitrusTest) which stands for defining the Citrus test just with Java domain specific language features. For now we continue to deal with the XML Citrus test execution.

The default naming convention requires a XML file with the tests name in the same package that the Java class is placed in. In the basic example above this means that Citrus searches for a XML test file in com/consol/citrus/samples/SampleIT.xml . You tell Citrus to search for another XML file by using the @CitrusXmlTest annotation properties. Following annotation properties are valid:

You can also mix the various CitrusXmlTest annotation patterns in a single Java class. So we are able to have several test cases in one single Java class. Each annotated method represents one or more Citrus XML test cases. Se the following example to see what this is about.

You are free to combine these test annotations as you like in your class. As the whole Java class is annotated with the TestNG @Test annotation each method gets executed automatically. Citrus will also take care on executing each XML test case as a separate unit test. So the test reports will have the exact number of executed tests and the JUnit/TestNG test reports do have the exact test outline for further usage (e.g. in continuous build reports).

The best thing about using the @CitrusXmlTest annotation is that you can continue to use the fabulous TestNG capabilities (e.g. test groups, invocation count, thread pools, data providers, and so on).

So now we have seen how to execute a Citrus XML test with TestNG.

Citrus as an application reads general settings from system properties and environment variables. The mechanism used is based on the property placeholder resource management. Application settings are read on startup by evaluating system properties first. After that environment variables get consulted for default values. If non of these is set the default value in Citrus sources is used.

This settings mechanism is well suited for both usual Java runtime environment and containerized runtime environments such as Docker or Kubernetes. Following from that you can overwrite general Citrus application settings by just providing a system property or environment variable on your local environment. The following settings do support this kind of environment configuration.

Same properties are settable via environment variables.

As mentioned in the previous section Citrus as a framework references some basic settings from system environment properties or variables. You can overwrite these settings in a central property file which is loaded at the very beginning of the Citrus runtime. The properties in that file are automatically loaded as Java system properties. Just add a property file named citrus-application.properties to your project classpath. This property file contains customized settings such as:

Citrus automatically loads these application properties at startup. All properties are also settable with Java system properties. The location of the citrus-application.properties file is customizable with the system property citrus.application.properties or environment variable CITRUS_APPLICATION_PROPERTIES.

You can use classpath: and file: path prefix in order to give locate a classpath or file-system resource.

Citrus starts a Spring application context and adds some default Spring bean components. By default Citrus will load some internal Spring Java config classes defining those bean components. At some point you might add some custom beans to that basic application context. This is why Citrus will search for custom Spring application context files in your project. These are automatically loaded.

By default Citrus looks for custom XML Spring application context files in this location: classpath:citrus-context.xml* . So you can add a file named citrus-context.xml to your project classpath and Citrus will load all Spring beans automatically.

The location of this file can be customized by setting a System property citrus.spring.application.context . So you can customize the XML Spring application context file location. The System property is settable with Maven surefire and failsafe plugin for instance or via Java before the Citrus framework gets loaded.

See the following sample XML configuration which is a normal Spring bean XML configuration:

Now you can add some Spring beans and you can use the Citrus XML components such as schema-repository for adding custom beans and components to your Citrus project. Citrus provides several namespaces for custom Spring XML components. These are described in more detail in the respective chapters and sections in this reference guide.

Using XML Spring application context configuration is the default behavior of Citrus. However some people might prefer pure Java code configuration. You can do that by adding a System property citrus.spring.java.config with a custom Spring Java config class as value.

Citrus will load the Spring bean configurations in MyCustomConfig.class as Java config then. See the following example for custom Spring Java configuration:

You can also mix XML and Java configuration so Citrus will load both configuration to the Spring bean application context on startup.

The <send> action in a test case publishes messages to a destination. The actual message transport connection is defined with the endpoint component. The test case simply defines the message contents and references a predefined message endpoint component by its identifier. Endpoint specific configurations are centralized in the Spring bean application context while multiple test cases can reference the endpoint to actually publish the constructed message to a destination. There are several message endpoint implementations in Citrus available representing different transport protocols like JMS, SOAP, HTTP, TCP/IP and many more.

Again the type of transport to use is not specified inside the test case but in the message endpoint definition. The separation of concerns (test case/message sender transport) gives us a good flexibility of our test cases. The test case does not know anything about connection factories, queue names or endpoint uri, connection timeouts and so on. The transport internals underneath a sending test action can change easily without affecting the test case definition. We will see later in this document how to create different message endpoints for various transports in Citrus. For now we concentrate on constructing the message content to be sent.

We assume that the message’s payload will be plain XML format. Citrus uses XML as the default data format for message payload data. But Citrus is not limited to XML message format though; you can always define other message data formats such as JSON, plain text, CSV. As XML is still a very popular message format in enterprise applications and message-based solution architectures we have this as a default format. Anyway Citrus works best on XML payloads and you will see a lot of example code in this document using XML. Finally let us have a look at a first example how a sending action is defined in the test.

Now lets have a closer look at the sending action. The 'endpoint' attribute might catch your attention first. This attribute references the message endpoint in Citrus configuration by its identifier. As previously mentioned the message endpoint definition lives in a separate configuration file and contains the actual message transport settings. In this example the "helloServiceEndpoint" is referenced which is a JMS endpoint for sending out messages to a JMS queue for instance.

The test case is not aware of any transport details, because it does not have to. The advantages are obvious: On the one hand multiple test cases can reference the message endpoint definition for better reuse. Secondly test cases are independent of message transport details. So connection factories, user credentials, endpoint uri values and so on are not present in the test case.

In other words the "endpoint" attribute of the <send> element specifies which message endpoint definition to use and therefore where the message should go to. Once again all available message endpoints are configured in a separate Citrus configuration file. Be sure to always pick the right message endpoint type in order to publish your message to the right destination.

If you do not like the XML language you can also use pure Java code to define the same test. In Java you would also make use of the message endpoint definition and reference this instance. The same test as shown above in Java DSL looks like this:

Instead of using the XML tags for send we use methods from TestNGCitrusTestDesigner class. The same message endpoint is referenced within the send message action. The payload is constructed as plain Java character sequence which is a bit verbose. We will see later on how we can improve this. For now it is important to understand the combination of send test action and a message endpoint.

This is basically how to send messages in Citrus. The test case is responsible for constructing the message content while the predefined message endpoint holds transport specific settings. Test cases reference endpoint components to publish messages to the outside world. This is just the start of action. Citrus supports a whole package of other ways how to define and manipulate the message contents. Read more about message sending actions in actions-send.

Now we have a look at the message receiving part inside the test. A simple example shows how it works.

If we recap the send action of the previous chapter we can identify some common mechanisms that apply for both sending and receiving actions. The test action also uses the endpoint attribute for referencing a predefined message endpoint. This time we want to receive a message from the endpoint. Again the test is not aware of the transport details such as JMS connections, endpoint uri, and so on. The message endpoint component encapsulates this information.

Before we go into detail on validating the received message we have a quick look at the Java DSL variation for the receive action. The same receive action as above looks like this in Java DSL.

The receive action waits for a message to arrive. The whole test execution is stopped while waiting for the message. This is important to ensure the step by step test workflow processing. Of course you can specify message timeouts so the receiver will only wait a given amount of time before raising a timeout error. Following from that timeout exception the test case fails as the message did not arrive in time. Citrus defines default timeout settings for all message receiving tasks.

At this point you know the two most important test actions in Citrus. Sending and receiving actions will become the main components of your integration tests when dealing with loosely coupled message based components in a enterprise application environment. It is very easy to create complex message flows, meaning a sequence of sending and receiving actions in your test case. You can replicate use cases and test your message exchange with extended message validation capabilities. See actions-receive for a more detailed description on how to validate incoming messages and how to expect message contents in a test case.

All messages that are sent and received during a test case are stored in a local memory storage. This is because we might want to access the message content later on in a test case. We can do so by using message store functions for loading messages that have been exchanged earlier in the test. When storing a message in the local storage Citrus uses a message name as identifier key. This message name is later on used to access the message. You can define the message name in any send or receive action:

The receive operation above set the message name to helloMessage. The message received is automatically stored in the local storage with that name. You can access the message content for instance by using a function:

The function loads the helloMessage and prints the payload information with the echo test action. In combination with Xpath or JsonPath functions this mechanism is a good way to access the exchanged message contents later in a test case.

When no explicit message name is given the local storage will construct a default message name. The default name is built from the action (send or receive) plus the endpoint used to exchange the message. For instance:

The names above would be generated by a send and receive operation on the endpoint named helloEndpoint.

Now we have seen the basic endpoint concept in Citrus. The endpoint components represent the connections to the test boundary systems. This is how we can connect to the system under test for message exchange. And this is our main goal with this integration test framework. We want to provide easy access to common message transports on client and server side so that we can test the communication interfaces on a real message transport exchange.

XML is a very common message format especially in the SOAP WebServices and JMS messaging world. Citrus provides XML message validator implementations that are able to compare XML message structures. The validator will notice differences in the XML message structure and supports XML namespaces, attributes and XML schema validation. The default XML message validator implementation is active by default and can be overwritten with a custom implementation using the bean id defaultXmlMessageValidator .

The default XML message validator is very powerful when it comes to compare XML structures. The validator supports namespaces with different prefixes and attributes als well as namespace qualified attributes. See the following sections for a detailed description of all capabilities.

Some elements in the message payload might not apply for validation at all. Just think of communication timestamps an dynamic values inside a message:

The timestamp value in our next example will dynamically change from test run to test run and is hardly predictable for the tester, so lets ignore it in validation.

Although we have given a static timestamp value in the payload data the element is ignored during validation as the ignore XPath expression matches the element. In addition to that we also ignored the version id element in this example. This time with an inline @ignore@ expression. This is for those of you that do not like XPath. As a result the ignored message elements are automatically skipped when Citrus compares and validates message contents and do not break the test case.

When using the Java DSL the @ignore@ placeholder as well as XPath expressions can be used seamlessly. Here is an example of that:

Of course you can use the inline @ignore@ placeholder in an external file resource, too.

Message formats such as JSON have become very popular, in particular when speaking of RESTful WebServices and JavaScript using JSON as the message format to go for. Citrus is able to expect and validate JSON messages as we will see in the next sections.

And this is quite easy. Citrus has a JSON message validator implementation active by default and immediately as we mark an incoming message as JSON data this message validator will jump in.

Citrus provides several default message validator implementations for JOSN message format:

You can also overwrite this default message validators for JSON by placing a bean into the Spring Application context. The bean uses a default name as identifier. Then your custom bean will overwrite the default validator:

This is how you can customize the message validators used for JSON message data.

We have mentioned before that Citrus is working with XML by default. This is why we have to tell Citrus that the message that we are receiving uses the JSON message format. We have to tell the test case receiving action that we expect a different format other than XML.

The message receiving action in our test case specifies a message format type type="json" . This tells Citrus to look for some message validator implementation capable of validating JSON messages. As we have added the proper message validator to the Spring application context Citrus will pick the right validator and JSON message validation is performed on this message. As you can see you we can use the usual test variables and the ignore element syntax here, too. Citrus is able to handle different JSON element orders when comparing received and expected JSON object. We can also use JSON arrays and nested objects. The default JSON message validator implementation in Citrus is very powerful in comparing JSON objects.

Instead of defining an expected message payload template we can also use Groovy validation scripts. Lets have a look at the Groovy JSON message validator example. As usual the default Groovy JSON message validator is active by default. But the special Groovy message validator implementation will only jump in when we used a validation script in our receive message definition. Let’s have an example for that.

Again we tell Citrus that we expect a message of type="json" . Now we used a validation script that is written in Groovy. Citrus will automatically activate the special message validator that executes our Groovy script. The script validation is more powerful as we can use the full power of the Groovy language. The validation script automatically has access to the incoming JSON message object json . We can use the Groovy JSON dot notated syntax in order to navigate through the JSON structure. The Groovy JSON slurper object json is automatically passed to the validation script. This way you can access the JSON object elements in your code doing some assertions.

There is even more object injection for the validation script. With the automatically added object receivedMessage You have access to the Citrus message object for this receive action. This enables you to do whatever you want with the message payload or header.

The listing above shows some power of the validation script. We can access the message payload, we can access the message header. With test context access we can also save the whole message payload as a new test variable for later usage in the test.

In general Groovy code inside the XML test case definition or as part of the Java DSL code is not very comfortable to maintain. You do not have code syntax assist or code completion. This is why we can also use external file resources for the validation scripts. The syntax looks like follows:

We referenced some external file resource validationScript.groovy . This file content is loaded at runtime and is used as script body. Now that we have a normal groovy file we can use the code completion and syntax highlighting of our favorite Groovy editor.

When we have multiple message validators that apply to the message format Citrus will execute all of them in sequence. In case you need to explicitly choose a message validator implementation you can do so in the receive action:

In this example we use the groovyJsonMessageValidator explicitly in the receive test action. The message validator implementation was added as Spring bean with id groovyJsonMessageValidator to the Spring application context before. Now Citrus will only execute the explicit message validator. Other implementations that might also apply are skipped.

So much for receiving JSON message data in Citrus. Of course sending JSON messages in Citrus is also very easy. Just use JSON message payloads in your sending message action.

When structured data is transmitted from one system to another, it’s important that the sender and the receiver understand each other. To ensure this, a contract is required introducing the rules of communication for both parties. This is mostly done by using schemas. Citrus brings the schema based validation of messages directly to your integration test environment. This includes the management, mapping and filtering of schemas in context to your current test case by just defining some rules in XML configuration or Java DSL. Let’s start with this chapter by introducing some basic concepts of the schema validation.

When Citrus receives plain Html messages we likely want to use the powerful XML validation capabilities such as XML tree comparison or XPath support. Unfortunately Html messages do not follow the XML well formed rules very strictly. This implies that XML message validation will fail because of non well formed Html code.

XHTML closes this gap by automatically fixing the most common Html XML incompatible rule violations such as missing end tags (e.g. <br>).

Let’s try this with a simple example. Very first thing for us to do is to add a new library dependency to the project. Citrus is using the jtidy library in order to prepare the HTML and XHTML messages for validation. As this 3rd party dependency is optional in Citrus we have to add it now to our project dependency list. Just add the jtidy dependency to your Maven project POM.

Please refer to the jtidy project documentation for the latest versions. Now everything is ready. As usual the Citrus message validator for XHTML is active in background by default. You can overwrite this default implementation by placing a Spring bean with id defaultXhtmlMessageValidator to the Citrus application context.

Now we can tell the test case receiving action that we want to use the XHTML message validation in our test case.

The message receiving action in our test case has to specify a message format type type="xhtml" . As you can see the Html message payload get XHTML specific DOCTYPE processing instruction. The xhtml1-strict.dtd is mandatory in the XHTML message validation. For better convenience all XHTML dtd files are packaged within Citrus so you can use this as a relative path.

The incoming Html message is automatically converted into proper XHTML code with well formed XML. So now the XHTML message validator can use the XML message validation mechanism of Citrus for comparing received and expected data. As usual you can use test variables, ignore element expressions and XPath expressions.

Plain text message validation is the easiest validation in Citrus that you can think of. This validation just performs an exact Java String match of received and expected message payloads.

As usual a default message validator for plaintext messages is active by default. Citrus will pick this message validator for all messages of type="plaintext" . The default message validator implementation can be overwritten by placing a Spring bean with id defaultPlaintextMessageValidator to the Spring application context.

In the test case receiving action we tell Citrus to use plain text message validation.

With the message format type type="plaintext" set Citrus performs String equals on the message payloads (received and expected). Only exact match will pass the test.

By the way sending plain text messages in Citrus is also very easy. Just use the plain text message payload data in your sending message action.

Of course test variables are supported in the plain text payloads. The variables are replace by the referenced values before sending or receiving the message.

Binary message validation is not very easy to do especially when it comes to compare data with a given control message. As a tester you want to validate the binary content. There are basically two ways in Citrus how to compare binary message content.

Gzip is a famous message compression library. When dealing with large message content the compression might be a good way to optimize the message transportation. Citrus is able to handle gzipped message payloads on send and receive operations. When sending compressed data we just have to use the message type gzip.

Just use the type="gzip" message type in the send operation. Citrus now converts the message payload to a gzip binary stream as payload.

When validating gzip binary message content the messages are compared with a given control message in binary base64 String representation. The gzip binary data is automatically unzipped and encoded as base64 character sequence in order to compare with an expected content.

The received message content is using gzip format but the actual message content does not have to be base64 encoded. Citrus is doing this conversion automatically before validation takes place. The binary data can be anything e.g. images, pdf or plaintext content.

The default message validator for gzip messages is active by default. Citrus will pick this message validator for all messages of type="gzip_base64" . The default message validator implementation can be overwritten by placing a Spring bean with id defaultGzipBinaryBase64MessageValidator to the Spring application context.

In the test case receiving action we tell Citrus to use gzip message validation.

With the message format type type="gzip_base64" Citrus performs the gzip base64 character sequence validation. Incoming message content is automatically unzipped and encoded as base64 String and compared to the expected data. This way we can make sure that the binary content is as expected.

The Java DSL offers some additional validation tricks and possibilities when dealing with messages that are sent and received over Citrus. One of them is the validation callback functionality. With this feature you can marshal/unmarshal message payloads and code validation steps on Java objects.

By default the validation callback needs some XML unmarshaller implementation for transforming the XML payload to a Java object. Citrus will automatically search for the unmarshaller bean in your Spring application context if nothing specific is set. Of course you can also set the unmarshaller instance explicitly.

Obviously working on Java objects is much more comfortable than using the XML String concatenation. This is why you can also use this feature when sending messages.

The example above creates a AddBookRequestMessage object and puts this as payload to a send action. In combination with a marshaller instance Citrus is able to create a proper XML message payload then.

In the previous sections we have already seen some examples on how to overwrite default message validator implementations in Citrus. By default all message validators can be overwritten by placing a Spring bean of the same id to the Spring application context. The default implementations of Citrus are:

Overwriting a single message validator with a custom implementation is then very easy. Just add your custom Spring bean to the application context using one of these default bean identifiers. In case you want to change the message validator gang by adding or removing a message validator implementation completely you can place a message validator component in the Spring application context.

The listing above adds a custom message validator implementation to the sequence of message validators in Citrus. We reference default message validators and add a implementation of type com.consol.citrus.validation.custom.CustomMessageValidator . The custom implementation class has to implement the basic interface com.consol.citrus.validation.MessageValidator . Now Citrus will try to match the custom implementation to incoming message types and occasionally execute the message validator logic. This is how you can add and change the basic message validator registry in Citrus. You can add custom implementations for new message formats very easy.

The same approach applies in case you want to remove a message validator implementation by banning it completely. Just delete the entry in the message validator registry component:

The Citrus message validator component deleted all default implementations except of those dealing with JSON message format. Now Citrus is only able to validate JSON messages. Be careful as the complete Citrus project will be affected by this change.

The previous section showed us how to customize the global set of available message validators in a Citrus project using the validator registry. Besides that you can also explicitly use a message validator in a receive test action. When using this approach the complete automatic message validator resolving mechanism is skipped and the receive action is using the defined validator implementation. Lets see this in a small example:

The receive action defines the message validator to use in this specific use case. You can set custom message validator implementations or use default implementations here.

You may want to set multiple validators here in order to meet your validation requirements. For instance when setting a DomXmlMessageValidator explicitly you may not be able to use the XpathMessageValidator capabilities on that specific receive action anymore. Fortunately you can set multiple validators on a receive action that will all perform validation tasks on the received message.

Some elements in XML message payloads might be of dynamic nature. Just think of generated identifiers or timestamps. Also we do not want to repeat the same static identifier several times in our test cases. This is the time where test variables and dynamic message element overwrite come in handy. The idea is simple. We want to overwrite a specific message element in our payload with a dynamic value. This can be done with XPath or inline variable declarations. Lets have a look at an example listing showing both ways:

The program listing above shows ways of setting variable values inside a message template. First of all you can simply place variable expressions inside the message (see how ${messageId} is used). In addition to that you can also use XPath expressions to explicitly overwrite message elements before validation.

<element path="/TestMessage/CreatedBy" value="${user}"/>

The XPath expression evaluates and searches for the right element in the message payload. The previously defined variable ${user} replaces the element value. Of course this works with XML attributes too.

Both ways via XPath or inline variable expressions are equal to each other. With respect to the complexity of XML namespaces and XPath you may find the inline variable expression more comfortable to use. Anyway feel free to choose the way that fits best for you. This is how we can add dynamic variable values to the control template in order to increase maintainability and robustness of message validation.

We have already seen how to validate whole XML structures with control message templates. All elements are validated and compared one after another. In some cases this approach might be too extensive. Imagine the tester only needs to validate a small subset of message elements. The definition of control templates in combination with several ignore statements is not appropriate in this case. You would rather want to use explicit element validation.

Instead of comparing the whole message some message elements are validated explicitly via XPath. Citrus evaluates the XPath expression on the received message and compares the result value to the control value. The basic message structure as well as all other message elements are not included into this explicit validation.

TestRequest.VersionId

The expression will search the XML tree for the respective <TestRequest><VersionId> element. Attributes are supported too. In case the last element in the dot-notated expression is a XML attribute the framework will automatically find it.

Of course this dot-notated syntax is very simple and might not be applicable for more complex tree navigation. XPath is much more powerful - no doubt. However the dot-notated syntax might help those of you that are not familiar with XPath. So the dot-notation is supported wherever XPath expressions might apply.

The Xpath expressions can evaluate to different result types. By default Citrus is operating on NODE and STRING result types so that you can validate some element value. But you can also use different result types such as NODESET and BOOLEAN . See this example how that works:

In the example above we use different expression result types. First we want to make sure nor /TestRequest/Error element is present. This can be done with a boolean result type and false value. Second we want to validate the number of found elements for the expression /TestRequest/Status[.='success'] . The XPath expression evaluates to a node list that results in its list size to be checked. And last not least we evaluate to a node-set result type where all values in the node list will be translated to a comma delimited string value.

Now lets have a look at some more powerful validation expressions using matcher implementations. Up to now we have seen that XPath expression results are comparable with equalTo operations. We would like to add some more powerful validation such as greaterThan, lessThan, hasSize and much more. Therefore we have introduced Hamcrest validation matcher support in Citrus. Hamcrest is a very powerful matcher library that provides a fantastic set of matcher implementations. Lets see how we can add these in our test case: