void hasPlugin(String alias, @DelegatesTo(strategy = Closure.DELEGATE_FIRST, value = PluginSpec) Closure<Void> spec) {
        assert model.hasPlugin(alias)
        def plugin = model.getPlugin(alias)
        assert plugin != null : "Expected a plugin with alias '$alias' but it wasn't found"
        def pluginSpec = new PluginSpec(plugin)
        spec.delegate = pluginSpec
        spec.resolveStrategy = Closure.DELEGATE_FIRST
        spec()
    }

                        }
                    }
                }
            """
            file("src/test/groovy/PluginSpec.groovy") << """
                import spock.lang.Specification

                class PluginSpec extends Specification {
                    def "dummy test"() {
                        expect:
                        true
                    }
                }

private
fun pluginSpecsFrom(pluginDescriptorsClassPath: ClassPath): Sequence<PluginTree.PluginSpec> =
    pluginDescriptorsClassPath
        .asFiles
        .asSequence()
        .filter { it.isFile && it.extension.equals("jar", true) }
        .flatMap { pluginEntriesFrom(it).asSequence() }
        .map { PluginTree.PluginSpec(it.pluginId, it.implementationClass) }


private

            String versionCatalogRef = buildContentGenerationContext.getVersionCatalogDependencyRegistry().registerPlugin(pluginId, version);
            plugin = new PluginSpec(versionCatalogRef, comment);
        } else {
            plugin = new PluginSpec(pluginId, version, comment);
        }
        block.plugins.add(plugin);
        return this;
    }

    /**