<artifactId>maven-core-it-support</artifactId>
      <version>1.3</version>
      <scope>runtime</scope>
      <exclusions>
        <exclusion>
          <groupId>commons-lang</groupId>
          <artifactId>commons-lang</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
  </dependencies>

        MavenProject project = session.getCurrentProject();

        Exclusion exclusion = new Exclusion();
        exclusion.setGroupId( "org.apache.maven.its" );
        exclusion.setArtifactId( "a" );

        new ProjectBuilder( project ).addDependency( "org.apache.maven.its", "b", "0.1", Artifact.SCOPE_RUNTIME,
                                                     exclusion );

        Set<Artifact> artifactDependencies =

                dependency.getOptional() != null ? dependency.isOptional() : null,
                exclusions);
    }

    private static Exclusion toExclusion(org.apache.maven.model.Exclusion exclusion) {
        return new Exclusion(exclusion.getGroupId(), exclusion.getArtifactId(), "*", "*");
    }

    public static ArtifactTypeRegistry newArtifactTypeRegistry(ArtifactHandlerManager handlerManager) {

            @Nonnull
            @Override
            public Collection<Exclusion> getExclusions() {
                return new MappedCollection<>(dependency.getExclusions(), this::toExclusion);
            }

            private Exclusion toExclusion(org.apache.maven.api.model.Exclusion exclusion) {
                return new Exclusion() {
                    @Nullable
                    @Override

      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t09-b</artifactId>
        <version>1.0</version>
        <exclusions>
          <exclusion>
            <groupId>maven-test</groupId>
            <artifactId>t09-c</artifactId>
          </exclusion>
        </exclusions>
      </dependency>

    </dependencies>

  </dependencyManagement>

      <artifactId>truth</artifactId>
      <version>${truth.version}</version>
      <scope>test</scope>
      <exclusions>
        <exclusion>
          <!-- use the guava we're building. -->
          <groupId>com.google.guava</groupId>
          <artifactId>guava</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>

      <artifactId>truth</artifactId>
      <version>${truth.version}</version>
      <scope>test</scope>
      <exclusions>
        <exclusion>
          <!-- use the guava we're building. -->
          <groupId>com.google.guava</groupId>
          <artifactId>guava</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>

            return addDependency(groupId, artifactId, version, scope, (Exclusion) null);
        }

        public ProjectBuilder addDependency(
                String groupId, String artifactId, String version, String scope, Exclusion exclusion) {
            return addDependency(groupId, artifactId, version, scope, null, exclusion);
        }

        public ProjectBuilder addDependency(

                Dependency source,
                boolean sourceDominant,
                Map<Object, Object> context) {
            List<Exclusion> tgt = target.getExclusions();
            if (tgt.isEmpty()) {
                List<Exclusion> src = source.getExclusions();
                builder.exclusions(src);
            }
        }
    }

        assertViolations(result, 0, 0, 2);

        assertContains(
                result.getWarnings().get(0),
                "'dependencies.dependency.exclusions.exclusion.groupId' for gid:aid:jar is missing");
        assertContains(
                result.getWarnings().get(1),
                "'dependencies.dependency.exclusions.exclusion.artifactId' for gid:aid:jar is missing");
    }

    @Test