fix: CLI Testing Library should now run in Node 12

Author: crutchcorn

src/__tests__/render-basics.js

@@ -1,9 +1,12 @@
 const {resolve} = require('path')
 const {render} = require('../pure')
+const {waitFor} = require('../wait-for')
 
 test('Should expect error codes when intended', async () => {
-  const instance = await render('node', [resolve(__dirname, './execute-scripts/throw.js')])
-  expect(instance.hasExit()).toMatchObject({exitCode: 1})
+  const instance = await render('node', [
+    resolve(__dirname, './execute-scripts/throw.js'),
+  ])
+  await waitFor(() => expect(instance.hasExit()).toMatchObject({exitCode: 1}))
 })
 
 test('Should handle argument passing', async () => {
@@ -20,7 +23,7 @@ test('Is able to make terminal input and view in-progress stdout', async () => {
     resolve(__dirname, './execute-scripts/stdio-inquirer.js'),
   ])
 
-  const {clear, findByText, userEvent} = props;
+  const {clear, findByText, userEvent} = props
 
   const instance = await findByText('First option')
 
@@ -31,13 +34,13 @@ test('Is able to make terminal input and view in-progress stdout', async () => {
 
   clear()
 
-  userEvent.keyboard("[ArrowDown]")
+  userEvent.keyboard('[ArrowDown]')
 
   expect(await findByText(/[❯>] Two/)).toBeTruthy()
 
   clear()
 
-  userEvent.keyboard("[Enter]")
+  userEvent.keyboard('[Enter]')
 
   expect(await findByText('First option: Two')).toBeTruthy()
 })

src/pure.ts

@@ -6,7 +6,7 @@ import {getQueriesForElement} from './get-queries-for-instance'
 import userEvent from './user-event'
 import {bindObjectFnsToInstance, setCurrentInstance} from './helpers'
 import {fireEvent} from './events'
-import {getConfig} from "./config";
+import {getConfig} from './config'
 
 const mountedInstances = new Set<TestInstance>()
 
@@ -25,18 +25,20 @@ async function render(
   })
 
   let _readyPromiseInternals: null | {resolve: Function; reject: Function} =
-      null
+    null
+
+  let _resolved = false
 
   const execOutputAPI = {
     __exitCode: null as null | number,
     _isOutputAPI: true,
     _isReady: new Promise(
-        (resolve, reject) => (_readyPromiseInternals = {resolve, reject}),
+      (resolve, reject) => (_readyPromiseInternals = {resolve, reject}),
     ),
     process: exec,
     // Clear buffer of stdout to do more accurate `t.regex` checks
     clear() {
-        execOutputAPI.stdoutArr = []
+      execOutputAPI.stdoutArr = []
     },
     // An array of strings gathered from stdout when unable to do
     // `await stdout` because of inquirer interactive prompts
@@ -50,30 +52,42 @@ async function render(
   mountedInstances.add(execOutputAPI as unknown as TestInstance)
 
   exec.stdout.on('data', (result: string | Buffer) => {
+    // `on('spawn') doesn't work the same way in Node12.
+    // Instead, we have to rely on this working as-expected.
+    if (_readyPromiseInternals && !_resolved) {
+      _readyPromiseInternals.resolve()
+      _resolved = true
+    }
+
     const resStr = stripFinalNewline(result as string)
     execOutputAPI.stdoutArr.push(resStr)
     _runObservers()
   })
 
   exec.stderr.on('data', (result: string | Buffer) => {
+    if (_readyPromiseInternals && !_resolved) {
+      _readyPromiseInternals.resolve()
+      _resolved = true
+    }
+
     const resStr = stripFinalNewline(result as string)
     execOutputAPI.stderrArr.push(resStr)
     _runObservers()
   })
 
   exec.on('error', result => {
     if (_readyPromiseInternals) {
-      _readyPromiseInternals.reject(result);
+      _readyPromiseInternals.reject(result)
     }
   })
 
   exec.on('spawn', () => {
-      setTimeout(() => {
-          if (_readyPromiseInternals) {
-
-              _readyPromiseInternals.resolve();
-          }
-  }, getConfig().renderAwaitTime)
+    setTimeout(() => {
+      if (_readyPromiseInternals && !_resolved) {
+        _readyPromiseInternals.resolve()
+        _resolved = true
+      }
+    }, getConfig().renderAwaitTime)
   })
 
   exec.on('exit', code => {
@@ -87,7 +101,7 @@ async function render(
   return Object.assign(
     execOutputAPI,
     {
-      userEvent: bindObjectFnsToInstance(execOutputAPI, userEvent)
+      userEvent: bindObjectFnsToInstance(execOutputAPI, userEvent),
     },
     getQueriesForElement(execOutputAPI),
   ) as TestInstance as RenderResult