fix(test-utils): use stdio transport for test server

Using the IPC transport, breaks code coverage. This is related to
bcoe/c8#189.

packages/test-utils/index.ts

@@ -12,16 +12,17 @@ export function startLanguageServer(serverModule: string, cwd?: string | URL) {
 
  const childProcess = cp.fork(
  serverModule,
- ['--node-ipc', `--clientProcessId=${process.pid.toString()}`],
+ ['--stdio', `--clientProcessId=${process.pid.toString()}`],
  {
  execArgv: ['--nolazy'],
  env: process.env,
  cwd,
+ stdio: 'pipe',
  }
  );
  const connection = _.createProtocolConnection(
- new _.IPCMessageReader(childProcess),
- new _.IPCMessageWriter(childProcess)
+ childProcess.stdout!,
+ childProcess.stdin!
  );
  const openedDocuments = new Map<string, TextDocument>();
  const settings: any = {};
@@ -34,7 +35,7 @@ export function startLanguageServer(serverModule: string, cwd?: string | URL) {
  connection.onUnhandledNotification(e => console.log(e));
  connection.onError(e => console.log(e));
  connection.onDispose(() => {
- childProcess.kill();
+ connection.end();
  });
  connection.onRequest(_.ConfigurationRequest.type, ({ items }) => {
  return items.map(item => {