Fake Maven Reactor, for Quick Unit Tests

It's a fake Maven Reactor, helping you to integration-test your custom Maven plugins. There is a traditional way to do this: Maven Invoker Plugin. It works perfectly, but it has two pretty annoying drawbacks: 1) It doesn't run from IDE (at least from IntelliJ IDEA), and 2) It always starts the entire build from scratch, which makes 3) it pretty slow.

Farea suggests an alternative way, which is way less flexible, but much faster and JUnit-friendly.

First, you add this to your pom.xml:

<dependency>
  <groupId>com.yegor256</groupId>
  <artifactId>farea</artifactId>
  <version>0.14.2</version>
</dependency>

Then, you use it like this, in your JUnit5 test (obviously, you need to have mvn installed and available on $PATH):

import com.yegor256.farea.Farea;
import com.yegor256.farea.RequisiteMatcher;
import org.hamcrest.MatcherAssert;
import org.hamcrest.Matchers;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.io.TempDir;

class JavaCompilationTest {
  @Test
  void worksAsExpected(@Mktmp Path dir) {
    new Farea(dir).together(f -> {
      f.files()
        .file("src/test/java/Hello.java")
        .write("class Hello {}".getBytes());
      f.dependencies().append("org.cactoos", "cactoos", "0.55.0");
      f.exec("compile");
      MatcherAssert.assertThat(
        "Compiles without any issues",
        f.files().log(),
        RequisiteMatcher.SUCCESS
      );
    });
  }
}

This code will create a new pom.xml file in the temporary directory, create a temporary Hello.java file, write simple content into it, add a new <dependency> to the pom.xml, and then run mvn test in this temporary directory. The output of the build will be saved to log.txt, which is available through the call to .log() method.

You can also test the plugin that you are developing, inside the same reactor:

class MyPluginTest {
  @Test
  void worksAsExpected(@Mktmp Path dir) {
    new Farea(dir).together(f -> {
      f.build()
        .plugins()
        .appendItself()
        .execution()
        .phase("test")
        .goals("my-custom-goal")
        .configuration()
        .set("message", "Hello, world!");
      f.exec("test");
      assert f.files().log().contains("SUCCESS");
    });
  }
}

Here, a .jar with the entire classpath will be packaged and saved into the ~/.m2/repository/ directory. This is almost exactly what the install goal of the invoker plugin would do if you use it for integration testing.

It is recommended to add this to your pom.xml, in order to enable interactive test runs right from the IDE:

<project>
  <build>
    <plugins>
      [...]
      <plugin>
        <artifactId>maven-resources-plugin</artifactId>
        <executions>
          <execution>
            <id>copy-descriptor</id>
            <phase>process-classes</phase>
            <goals>
              <goal>copy-resources</goal>
            </goals>
            <configuration>
              <outputDirectory>${project.build.directory}</outputDirectory>
              <resources>
                <resource>
                  <directory>${project.build.outputDirectory}/META-INF/maven</directory>
                  <includes>
                    <include>plugin.xml</include>
                  </includes>
                </resource>
              </resources>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

This will make sure the META-INF/maven/plugin.xml is not destroyed in the target/classes by the IDE before the next test run.

See how antlr2ebnf-maven-plugin is using Farea.

How to Contribute

Fork repository, make changes, send us a pull request. We will review your changes and apply them to the master branch shortly, provided they don't violate our quality standards. To avoid frustration, before sending us your pull request please run full Maven build:

mvn clean install -Pqulice

You will need Maven 3.3+ and Java 11+.