title: component lookup exception with org.apache.maven.repository.RepositorySystem in Maven plugin testing
body: <p>I'm trying to use <code>maven-plugin-testing-harness</code> version 2.1 with the following test case:</p>
  
  <pre><code>public class FooTest extends AbstractMojoTestCase {
    @Override
    protected void setUp() throws Exception {
      super.setUp();
    }
    public void testSomething() throws Exception {
      // todo
    }
  }
  </code></pre>
  
  <p>The test fails at the <code>setUp()</code> call:</p>
  
  <pre><code>org.codehaus.plexus.component.repository.exception.ComponentLookupException: java.util.NoSuchElementException
    role: org.apache.maven.repository.RepositorySystem
  roleHint: 
      at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:257)
      at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:245)
      at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:239)
      at org.codehaus.plexus.PlexusTestCase.lookup(PlexusTestCase.java:206)
      at org.apache.maven.plugin.testing.AbstractMojoTestCase.setUp(AbstractMojoTestCase.java:118)
      at foo.FooTest.setUp(FooTest.java:54)
  </code></pre>
  
  <p>These dependencies I have in the <code>pom.xml</code>:</p>
  
  <pre><code>    &lt;dependency&gt;
          &lt;groupId&gt;org.apache.maven&lt;/groupId&gt;
          &lt;artifactId&gt;maven-plugin-api&lt;/artifactId&gt;
          &lt;version&gt;3.0.5&lt;/version&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.apache.maven&lt;/groupId&gt;
          &lt;artifactId&gt;maven-model&lt;/artifactId&gt;
          &lt;version&gt;3.0.5&lt;/version&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.apache.maven&lt;/groupId&gt;
          &lt;artifactId&gt;maven-core&lt;/artifactId&gt;
          &lt;version&gt;3.0.5&lt;/version&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.apache.maven.plugin-testing&lt;/groupId&gt;
          &lt;artifactId&gt;maven-plugin-testing-harness&lt;/artifactId&gt;
          &lt;version&gt;2.1&lt;/version&gt;
          &lt;scope&gt;test&lt;/scope&gt;
      &lt;/dependency&gt;
  </code></pre>
  
  <p>Any ideas?</p>