private static final String GROUP_ID = "test";

    // fields -----------------------------------------------------------------

    protected Artifact a1;

    protected Artifact a2;

    protected Artifact b1;

    private final String roleHint;

    @Inject
    private ArtifactFactory artifactFactory;

    private ConflictResolver conflictResolver;

    @Inject
    protected PlexusContainer container;

     * <pre>
     * a:1.0
     * b:1.0 -&gt; a:2.0
     * </pre>
     */
    @Test
    void testDepth() {
        ResolutionNode a1n = createResolutionNode(a1);
        ResolutionNode b1n = createResolutionNode(b1);
        ResolutionNode a2n = createResolutionNode(a2, b1n);

        assertResolveConflict(a2n, a1n, a2n);
    }

    /**
     * Tests that <code>a:2.0</code> wins in the scenario:
     * <pre>

     * <pre>
     * a:1.0
     * b:1.0 -&gt; a:2.0
     * </pre>
     */
    @Test
    void testDepth() {
        ResolutionNode a1n = createResolutionNode(a1);
        ResolutionNode b1n = createResolutionNode(b1);
        ResolutionNode a2n = createResolutionNode(a2, b1n);

        assertResolveConflict(a2n, a1n, a2n);
    }

    /**
     * Tests that <code>a:2.0</code> wins in the scenario:
     * <pre>

     * <pre>
     * a:1.0
     * b:1.0 -&gt; a:2.0
     * </pre>
     */
    @Test
    void testDepth() {
        ResolutionNode a1n = createResolutionNode(a1);
        ResolutionNode b1n = createResolutionNode(b1);
        ResolutionNode a2n = createResolutionNode(a2, b1n);

        assertResolveConflict(a1n, a1n, a2n);
    }

    /**
     * Tests that <code>a:1.0</code> wins in the scenario:
     * <pre>

     * <pre>
     * a:1.0
     * b:1.0 -&gt; a:2.0
     * </pre>
     */
    @Test
    void testDepth() {
        ResolutionNode a1n = createResolutionNode(a1);
        ResolutionNode b1n = createResolutionNode(b1);
        ResolutionNode a2n = createResolutionNode(a2, b1n);

        assertResolveConflict(a1n, a1n, a2n);
    }

    /**
     * Tests that <code>a:1.0</code> wins in the scenario:
     * <pre>

        // TODO use newest conflict resolver
        ArtifactSpec a = createArtifactSpec("a", "1.0");
        ArtifactSpec b1 = a.addDependency("b", "1.0");
        ArtifactSpec c = a.addDependency("c", "1.0");
        ArtifactSpec d2 = b1.addDependency("d", "2.0");
        d2.addDependency("h", "1.0");
        ArtifactSpec d1 = c.addDependency("d", "1.0");

   * products that you would get from nesting for loops:
   *
   * <pre>{@code
   * for (B b0 : sets.get(0)) {
   *   for (B b1 : sets.get(1)) {
   *     ...
   *     ImmutableList<B> tuple = ImmutableList.of(b0, b1, ...);
   *     // operate on tuple
   *   }
   * }
   * }</pre>
   *