def "language level is null if matching calculated idea project language level"() {
        given:
        project.getPlugins().apply(IdeaPlugin)
        project.getPlugins().apply(JavaPlugin)
        moduleProject.getPlugins().apply(JavaPlugin)
        moduleProject.sourceCompatibility = 1.5
        project.sourceCompatibility = 1.5

        def iml = Mock(IdeaModuleIml)
        def module = TestUtil.newInstance(IdeaModule, moduleProject, iml)

        plugin.setArtifactId(pluginInfo.artifactId);
        plugin.setName(pluginInfo.name);
        result.getPlugins().add(plugin);
        return result;
    }

    @Override
    protected void merge(Metadata recessive) {
        List<Plugin> recessivePlugins = recessive.getPlugins();
        List<Plugin> plugins = metadata.getPlugins();
        if (!recessivePlugins.isEmpty() || !plugins.isEmpty()) {

        // just carry-on as-is
        if (recessive.getPlugins() != null && !recessive.getPlugins().isEmpty()) {
            metadata = metadata.withPlugins(new ArrayList<>(recessive.getPlugins()));
        }
    }

    private static int getBuildNumber(Metadata metadata) {
        int number = 0;

        }

        metadata = metadata.withVersioning(versioning.build());

        // just carry-on as-is
        if (recessive.getPlugins() != null && !recessive.getPlugins().isEmpty()) {
            metadata = metadata.withPlugins(new ArrayList<>(recessive.getPlugins()));
        }
    }

    public Object getKey() {
        return getGroupId() + ':' + getArtifactId();
    }

        if (build != null) {
            build = build.withPlugins(expandPlugin(build.getPlugins()));
            PluginManagement pluginManagement = build.getPluginManagement();
            if (pluginManagement != null) {
                build = build.withPluginManagement(
                        pluginManagement.withPlugins(expandPlugin(pluginManagement.getPlugins())));
            }
            model = model.withBuild(build);
        }

                PluginContainer source,
                boolean sourceDominant,
                Map<Object, Object> context) {
            List<Plugin> src = source.getPlugins();
            if (!src.isEmpty()) {
                List<Plugin> tgt = target.getPlugins();

                Map<Object, Plugin> merged = new LinkedHashMap<>((src.size() + tgt.size()) * 2);

                for (Plugin element : tgt) {

import org.gradle.api.Plugin;
import org.gradle.api.Project;

public class MyPlugin implements Plugin<Project> {
    public void apply(Project project) {
        project.getPlugins().apply(MyBasePlugin.class);

        // define conventions
    }

        // just carry-on as-is
        if (recessive.getPlugins() != null && !recessive.getPlugins().isEmpty()) {
            metadata = metadata.withPlugins(new ArrayList<>(recessive.getPlugins()));
        }

        artifacts.clear();
    }

    private String getKey(String classifier, String extension) {

            }
        }

        metadata.getVersioning().setSnapshotVersions(new ArrayList<>(versions.values()));

        // just carry-on as-is
        if (!recessive.getPlugins().isEmpty()) {
            metadata.setPlugins(new ArrayList<>(recessive.getPlugins()));
        }

        artifacts.clear();
    }

    private String getKey(String classifier, String extension) {
        return classifier + ':' + extension;

        // prepare testReportDirectory with a reasonable default, but override with JavaPluginExtension#testReportDirectory if available
        project.getPlugins().withId("java-base", plugin -> {
            JavaPluginExtension javaPluginExtension = project.getExtensions().getByType(JavaPluginExtension.class);
            testReportDirectory.convention(javaPluginExtension.getTestReportDir());