### Question:
DefaultExtensionRegistry implements ExtensionRegistry { public Registry getRegistry() { return registry; } DefaultExtensionRegistry(Registry registry); static DefaultExtensionRegistry fromURLs(Collection<URL> urls); static DefaultExtensionRegistry fromPlatform(QuarkusPlatformDescriptor platform); @Override Set<String> getQuarkusCoreVersions(); @Override Set<Extension> getExtensionsByCoreVersion(String version); @Override Set<Extension> list(String quarkusCore, String keyword); @Override ExtensionInstallPlan planInstallation(String quarkusCore, Collection<String> keywords); Registry getRegistry();  }### Answer:
@Test void serializationShouldKeepValues(@TempDir Path tmpDir) throws IOException { File tmpFile = tmpDir.resolve("registry.json").toFile(); OBJECT_MAPPER.writeValue(tmpFile, extensionRegistry.getRegistry()); Registry newRegistry = OBJECT_MAPPER.readValue(tmpFile, Registry.class); assertThat(newRegistry).isEqualToComparingFieldByField(extensionRegistry.getRegistry()); }