UnresolvableModelException e = assertThrows(
                UnresolvableModelException.class,
                () -> newModelResolver().resolveModel(parent.getDelegate(), new AtomicReference<>()),
                "Expected 'UnresolvableModelException' not thrown.");
        assertNotNull(e.getMessage());
        assertThat(e.getMessage(), containsString("Could not find artifact org.apache:apache:pom:0 in central"));
    }

    @Test

        Path tempFile = Files.createTempFile("", ".pom");
        Files.delete(tempFile);
        try (InputStream expected = Files.newInputStream(beforePomFile)) {
            Model model = new Model(new MavenStaxReader().read(expected));
            MavenProject project = new MavenProject(model);
            project.setOriginalModel(model);

        ExecutionPlanItem expected = plan.findLastInPhase("package");
        ExecutionPlanItem beerPhase = plan.findLastInPhase("BEER"); // Beer comes straight after package in stub
        assertEquals(expected, beerPhase);
        assertNotNull(expected);
    }

    @Test
    void testThreadSafeMojos() throws Exception {

        ModelResolverException e = assertThrows(
                ModelResolverException.class,
                () -> newModelResolver().resolveModel(session, parent, new AtomicReference<>()),
                "Expected 'ModelResolverException' not thrown.");
        assertNotNull(e.getMessage());
        assertThat(e.getMessage(), containsString("Could not find artifact org.apache:apache:pom:0 in central"));
    }

    @Test

     * @param oldValue the expected data currently associated with the key, may be {@code null}
     * @param newValue the data to associate with the key, may be {@code null} to remove the mapping
     * @return {@code true} if the key mapping was successfully updated from the old value to the new value,
     *         {@code false} if the current key mapping didn't match the expected value and was not updated.
     */

These stubs form an internally consistent data-set that is not expected to change. They are
used to test the individual components in the lifecycle with data that has expected characteristics
and can be asserted as desired.

You can change/extend these stubs, and tests should not be breaking too much, since most tests
assert using expected values from the stubs. Normally, when you try to use data from the stubs that

    /**
     * Copies the values from the given toolchains into the specified execution request. This method will replace any
     * existing values in the execution request that are controlled by the toolchains. Hence, it is expected that this
     * method is called on a new/empty execution request before the caller mutates it to fit its needs.
     *
     * @param request The execution request to populate, must not be {@code null}.

        ResolutionNode resolvedNode = getConflictResolver().resolveConflict(actualNode1, actualNode2);

        assertNotNull(resolvedNode, "Expected resolvable");
        assertEquals(expectedNode, resolvedNode, "Resolution node");
    }

    protected Artifact createArtifact(String id, String version) throws InvalidVersionSpecificationException {

/**
 * Handles profile injection into the model.
 *
 */
public interface ProfileInjector {

    /**
     * Merges values from the specified profile into the given model. Implementations are expected to keep the profile
     * and model completely decoupled by injecting deep copies rather than the original objects from the profile.
     *

                .map(Dependency::getArtifact)
                .filter(d -> "org.apache.maven".equals(d.getGroupId()))
                .filter(d -> !DefaultPluginValidationManager.EXPECTED_PROVIDED_SCOPE_EXCLUSIONS_GA.contains(
                        d.getGroupId() + ":" + d.getArtifactId()))
                .map(Artifact::getVersion)
                .filter(v -> v.startsWith("2."))