when(project.getArtifactId()).thenReturn("maven-embedder");
        when(project.getPackaging()).thenReturn("jar");
        when(project.getName()).thenReturn("Apache Maven Embedder");
        when(project.getVersion()).thenReturn("3.5.4-SNAPSHOT");
        when(project.getFile()).thenReturn(new File(basedir, "maven-embedder/pom.xml"));
        when(event.getProject()).thenReturn(project);

   * The HTTP <a href="https://wicg.github.io/cross-origin-embedder-policy/#COEP">{@code
   * Cross-Origin-Embedder-Policy}</a> header field name.
   *
   * @since 30.0
   */
  public static final String CROSS_ORIGIN_EMBEDDER_POLICY = "Cross-Origin-Embedder-Policy";

  /**
   * The HTTP <a href="https://wicg.github.io/cross-origin-embedder-policy/#COEP-RO">{@code
   * Cross-Origin-Embedder-Policy-Report-Only}</a> header field name.
   *

  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-cli</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-embedder</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-core</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>

  project
- nice little sample projects that could be run in the core as well as integration tests

All Possible Errors
- invalid lifecycle phase (maybe same as bad CLI param, though you were talking about embedder too)
- <module> specified is not found
- malformed settings
- malformed POM
- local repository not writable
- remote repositories not available
- artifact metadata missing
- extension metadata missing

    private boolean isProjectPresent = true;

    // ----------------------------------------------------------------------------
    // We need to allow per execution user and global settings as the embedder
    // might be running in a mode where it's executing many threads with totally
    // different settings.
    // ----------------------------------------------------------------------------