Function setup

packages/language-service/test/legacy/mock_host.ts:153–179

()

 * and modify test files.
 */
export function setup() {
  const configFileFs = new MockConfigFileFs();
  const projectService = new ts.server.ProjectService({
    host: createHost(configFileFs),
    logger,
    cancellationToken: ts.server.nullCancellationToken,
    useSingleInferredProject: true,
    useInferredProjectPerProjectRoot: true,
    typingsInstaller: ts.server.nullTypingsInstaller,
    session: undefined,
  });
  // Opening APP_COMPONENT forces a new ConfiguredProject to be created based
  // on the tsconfig.json in the test project.
  projectService.openClientFile(APP_COMPONENT);
  const project = projectService.findProject(TSCONFIG);
  if (!project) {
    throw new Error(`Failed to create project for ${TSCONFIG}`);
  }
  // The following operation forces a ts.Program to be created.
  const tsLS = project.getLanguageService();
  return {
    service: new MockService(project, projectService),
    project,
    tsLS,
    configFileFs,
  };
}

interface OverwriteResult {
  /**