spec: It is not certain which process starts first

spec/api-app-spec.js

@@ -162,23 +162,18 @@ describe('app module', function () {
       this.timeout(120000)
       const appPath = path.join(__dirname, 'fixtures', 'api', 'singleton')
       // First launch should exit with 0.
-      let exited = 0
       const first = ChildProcess.spawn(remote.process.execPath, [appPath])
       first.once('exit', (code) => {
         assert.equal(code, 0)
-        exited++
-        if (exited === 2) {
-          done()
-        }
       })
-      // Second launch should exit with 1.
-      const second = ChildProcess.spawn(remote.process.execPath, [appPath])
-      second.once('exit', (code) => {
-        assert.equal(code, 1)
-        exited++
-        if (exited === 2) {
+      // Start second app when received output.
+      first.stdout.once('data', () => {
+        // Second launch should exit with 1.
+        const second = ChildProcess.spawn(remote.process.execPath, [appPath])
+        second.once('exit', (code) => {
+          assert.equal(code, 1)
           done()
-        }
+        })
       })
     })
   })

spec/fixtures/api/singleton/main.js

@@ -1,8 +1,6 @@
 const {app} = require('electron')
 
-process.on('uncaughtException', () => {
-  app.exit(2)
-})
+console.log('started')  // ping parent
 
 const shouldExit = app.makeSingleInstance(() => {
   process.nextTick(() => app.exit(0))