How to test maven plugin using JUnit4

Question

I am writing a maven plugin and want to write some JUnit tests. I followed the description in Maven Plugin Testing . Unfortunately, I continue to get an exception during test setup before I can configure or call anything.

This is my JUnit test code:

public class ResetMojoTest {

    private static final String POM_FILE_NAME = "/path/to/pom.xml"; 

    @Rule
    public MojoRule rule = new MojoRule();

    @Test
    public void testSomething()
        throws Exception
    {
        File pom = new File(POM_FILE_NAME);
        Assert.assertNotNull( pom );
        Assert.assertTrue( pom.exists() );

        ResetMojo resetMojo = (ResetMojo) rule.lookupMojo( "touch", pom );
        Assert.assertNotNull( resetMojo );
        resetMojo.execute();
    }

}

And this is the exception stack trace:

java.io.IOException: Stream closed
    at java.io.BufferedInputStream.getInIfOpen(BufferedInputStream.java:134)
    at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
    at org.apache.commons.io.input.BOMInputStream.getBOM(BOMInputStream.java:175)
    at org.apache.commons.io.input.BOMInputStream.getBOMCharsetName(BOMInputStream.java:201)
    at org.apache.commons.io.input.XmlStreamReader.doRawStream(XmlStreamReader.java:412)
    at org.apache.commons.io.input.XmlStreamReader.<init>(XmlStreamReader.java:206)
    at org.apache.commons.io.input.XmlStreamReader.<init>(XmlStreamReader.java:171)
    at org.apache.commons.io.input.XmlStreamReader.<init>(XmlStreamReader.java:140)
    at org.apache.maven.plugin.testing.AbstractMojoTestCase.setUp(AbstractMojoTestCase.java:119)
    at org.apache.maven.plugin.testing.MojoRule$2.evaluate(MojoRule.java:299)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)

Any ideas on how to do this?

Answer 1

. mojo , AbstractMojoTestCase, , , : InputStream is = getClass().getResourceAsStream( "/" + getPluginDescriptorLocation() );. (getPluginDescriptorLocation()) - "META-INF/maven/plugin.xml".

, :

<dependency>
  <groupId>org.apache.maven</groupId>
  <artifactId>maven-compat</artifactId>
  <version>3.5.0</version>
</dependency>

, . ( , target , ). , , .

.

<dependency>
  <groupId>org.apache.maven</groupId>
  <artifactId>maven-plugin-api</artifactId>
  <version>3.5.0</version>
</dependency>
<dependency>
  <groupId>org.twdata.maven</groupId>
  <artifactId>mojo-executor</artifactId>
  <version>2.3.0</version>
</dependency>
<dependency>
  <groupId>org.apache.maven.plugin-tools</groupId>
  <artifactId>maven-plugin-annotations</artifactId>
  <version>3.5</version>
  <scope>provided</scope>
</dependency>
<dependency>
  <groupId>org.eclipse.aether</groupId>
  <artifactId>aether-api</artifactId>
  <version>1.1.0</version>
</dependency>
<dependency>
  <groupId>org.apache.maven</groupId>
  <artifactId>maven-core</artifactId>
  <version>3.5.0</version>
</dependency>
<dependency>
  <groupId>org.apache.maven</groupId>
  <artifactId>maven-compat</artifactId>
  <version>3.5.0</version>
</dependency>
<!--Test Dependencies-->
<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.12</version>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>org.apache.maven.plugin-testing</groupId>
  <artifactId>maven-plugin-testing-harness</artifactId>
  <version>3.3.0</version>
  <scope>test</scope>
</dependency>

Answer 2

POM :

:

File pom = rule.getTestFile( "src/test/resources/unit/project-to-test/pom.xml" );

, :

File pom = new File(POM_FILE_NAME);

, , :

private static final String POM_FILE_NAME = "/path/to/pom.xml"; 

pom :

private static final String POM_FILE_NAME = "src/test/resources/pom.xml";