One of the most common points of discussion when starting the development of a test automation project is how will the tests be distributed and executed. When working with Java, an executable JAR file could be a good option to solve this. The benefits of taking this approach are:
- Tests can be easily distributed among teams by just sharing a single JAR file.
- Code is protected from any intended or unintended modification that could impact the accuracy of the test results.
- Tests can be executed with less required setup. There is no need for an IDE (Integrated Development Environment), version control system and JDK (Java Development Kit), to be able to pull code, compile and run the tests. Having JRE (Java Runtime Environment) properly configured should be enough.
Assumptions
We are dealing with a “stand-alone” test, meaning we don’t have a main source code to test in the same project. Instead, the test source code contains all that is required to execute the test. A common scenario is a UI functional testing of a web app using Selenium, where we just need access to the app through a URL, and all the page classes and tests are contained in a single source of code.
Also, this implementation assumes maven keeps the default directory structure:
src/main/java
src/main/resources
src/test/java
src/test/resources
There are two approaches that can be used:
A. Test code is in “main”
- The test code and resources are contained in (or moved to) the main module
src/main/java
andsrc/main/resources
- Create a
Main
class where you can start the execution from. Example:
public class TestMainRunner {
public static void main(String[] args) {
String[] cucumberArgs = new String[] {
"-g","steps",
"classpath:features",
"-p", "pretty"
};
Main.run(cucumberArgs);
}
}
- Add
maven-assembly-plugin
topom.xml
to enable creating a.jar
file including the project dependencies and also to specify the main class to be executed when running the.jar
:
<build>
<plugins>
...
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package
<goals>
<goal>single
</goals>
</execution>
</executions>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>run.TestMainRunner</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
...
</build>
</plugins>
To generate the .jar file run from terminal:
mvn clean compile assembly:single
jar file is output to target
folder
- Define
src/main/java
andsrc/main/resources
as test source and resources in thepom.xml
:
<build>
...
<testSourceDirectory>
src/main/java
</testSourceDirectory>
<testResources>
<testResource>
<directory>src/main/resources</directory>
</testResource>
</testResources>
...
</build>
By doing this, test can be executed by running from the terminal:
mvn test
Note: When executing mvn test
, test-classes
folder is generated in target
with same content as classes
. That might cause some warning during execution, nothing to worry about.
B. Test code is in “test”
In case tests are developed under test
module and there is not option to move them to main
, this could one helpful approach.
- The test code and resources are contained in (or moved to) the test module
src/test/java
andsrc/test/resources
- Create a
Main
class where you can start the execution from. Example:
public class TestMainRunner {
public static void main(String[] args) {
String[] cucumberArgs = new String[] {
"-g","steps",
"classpath:features",
"-p", "pretty"
};
Main.run(cucumberArgs);
}
}
- Add
maven-assembly-plugin
topom.xml
to enable creating a.jar
file including the project dependencies and also to specify the main class to be executed when running the.jar
:
<build>
<plugins>
...
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>run.TestMainRunner</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
...
</build>
</plugins>
To generate the .jar file run from terminal:
mvn clean compile assembly:single
jar file is output to target folder
mvn test
can be executed without any modification to thepom.xml
file, since tests are contained in the default directory defined by maven.- A last tweak required to execute the tests from the IDE (▶️), is to specify the resources directory in the
pom.xml
:
<build>
...
<!-- Required to execute from IDE when running feature directly -->
<resources>
<resource>
<directory>src/test/resources</directory>
</resource>
</resources>
...
</build>