Maven Integration Tests in Extra Source Folder

On one of my current projects we want to separate the fast unit tests from the slow running integration and acceptance tests. Using Maven this is not possible out of the box because Maven only supports two source folders, main and test. How can we add another source and resource folder, e.g. it (for integration test)? Let's assume a project layout like that:

project
|-- pom.xml
`-- src
    |-- main
        `-- java
    |-- test
        `-- java
            `-- UnitTest.java
    `-- it
        `-- java
            `-- IntegrationIT.java

We use the regular Maven Surefire to execute our unit tests, i.e. all the tests in the src/test/java folder. The plugin definition in the pom.xml is as expected.

        <plugin>
            <!-- run the regular tests -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>2.18</version>
        </plugin>

And we use Maven Failsafe to execute the integration tests. If you do not know Failsafe, it is much like the Surefire plugin, but with different defaults and usually runs during the integration test phase.

        <plugin>
            <!-- run the integration tests -->
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-failsafe-plugin</artifactId>
            <version>2.18.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>integration-test</goal>
                        <goal>verify</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

By default the Failsafe plugin does not look for class names ending with Test but ending with IT, making it possible to mix both kind of tests in the same src/test/java folder, but we do not want that. The "trick" to have another source folder for integration tests is to use the Build Helper Maven Plugin and add it as test source.

        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>build-helper-maven-plugin</artifactId>
            <version>1.9.1</version>
            <executions>
                <execution>
                    <id>add-integration-test-source-as-test-sources</id>
                    <phase>generate-test-sources</phase>
                    <goals>
                        <goal>add-test-source</goal>
                    </goals>
                    <configuration>
                        <sources>
                            <source>src/it/java</source>
                        </sources>
                    </configuration>
                </execution>
            </executions>
        </plugin>

Now src/it/java is added as test source as well, as seen during Maven execution. After the compile phase Maven logs

[INFO] [build-helper:add-test-source {execution: add-integration-test-source-as-test-sources}]
[INFO] Test Source directory: .\src\it\java added.

There is still only one test source for Maven but at least we have two folders in the file system. All test sources get merged and during the test compile phase we see

[INFO] [compiler:testCompile {execution: default-testCompile}]
[INFO] Compiling 2 source files to .\target\test-classes

showing that all classes in both src/test/java and src/it/java are compiled at the same time. This is important to know because class names must not clash and tests still need different naming conventions like *Test and *IT. Now mvn test will only execute fast unit tests and can be rerun many times during development.

[INFO] [surefire:test {execution: default-test}]
[INFO] Surefire report directory: .\target\surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running UnitTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.01 sec - in UnitTest

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

Only if we want, using mvn verify, the integration tests are executed.

[INFO] [failsafe:integration-test {execution: default}]
[INFO] Failsafe report directory: .\target\failsafe-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running IntegrationIT
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec - in IntegrationIT

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

[INFO] [failsafe:verify {execution: default}]
[INFO] Failsafe report directory: .\target\failsafe-reports

Now we can run the slow tests before we check in the code or after major changes a few times during the day.