chore: add helper for getting Jest's config in e2e tests (#9770)

Author: SimenB

e2e/__tests__/config.test.ts

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import runJest from '../runJest';
+import runJest, {getConfig} from '../runJest';
 
 test('config as JSON', () => {
   const result = runJest('verbose-reporter', [
@@ -70,14 +70,11 @@ test('works with jsdom testEnvironmentOptions config JSON', () => {
 });
 
 test('negated flags override previous flags', () => {
-  const {stdout} = runJest('verbose-reporter', [
-    '--show-config',
+  const {globalConfig} = getConfig('verbose-reporter', [
     '--silent',
     '--no-silent',
     '--silent',
   ]);
 
-  const parsedConfig = JSON.parse(stdout);
-
-  expect(parsedConfig.globalConfig.silent).toEqual(true);
+  expect(globalConfig.silent).toEqual(true);
 });

e2e/__tests__/esmConfigFile.test.ts

@@ -6,44 +6,41 @@
  */
 
 import {onNodeVersions} from '@jest/test-utils';
-import {json as runWithJson} from '../runJest';
+import {getConfig} from '../runJest';
 
 test('reads config from cjs file', () => {
-  const {json, exitCode} = runWithJson('esm-config/cjs', ['--show-config'], {
+  const {configs} = getConfig('esm-config/cjs', [], {
     skipPkgJsonCheck: true,
   });
 
-  expect(exitCode).toBe(0);
-  expect(json.configs).toHaveLength(1);
-  expect(json.configs[0].displayName).toEqual({
+  expect(configs).toHaveLength(1);
+  expect(configs[0].displayName).toEqual({
     color: 'white',
     name: 'Config from cjs file',
   });
 });
 
 // not unflagged for other versions yet. Update this range if that changes
-onNodeVersions('^13.2.0', () => {
+onNodeVersions('>=13.2.0', () => {
   test('reads config from mjs file', () => {
-    const {json, exitCode} = runWithJson('esm-config/mjs', ['--show-config'], {
+    const {configs} = getConfig('esm-config/mjs', [], {
       skipPkgJsonCheck: true,
     });
 
-    expect(exitCode).toBe(0);
-    expect(json.configs).toHaveLength(1);
-    expect(json.configs[0].displayName).toEqual({
+    expect(configs).toHaveLength(1);
+    expect(configs[0].displayName).toEqual({
       color: 'white',
       name: 'Config from mjs file',
     });
   });
 
   test('reads config from js file when package.json#type=module', () => {
-    const {json, exitCode} = runWithJson('esm-config/js', ['--show-config'], {
+    const {configs} = getConfig('esm-config/js', [], {
       skipPkgJsonCheck: true,
     });
 
-    expect(exitCode).toBe(0);
-    expect(json.configs).toHaveLength(1);
-    expect(json.configs[0].displayName).toEqual({
+    expect(configs).toHaveLength(1);
+    expect(configs[0].displayName).toEqual({
       color: 'white',
       name: 'Config from js file',
     });

e2e/__tests__/multiProjectRunner.test.ts

@@ -9,7 +9,7 @@ import {tmpdir} from 'os';
 import * as path from 'path';
 import {wrap} from 'jest-snapshot-serializer-raw';
 import {cleanup, extractSummary, sortLines, writeFiles} from '../Utils';
-import runJest from '../runJest';
+import runJest, {getConfig} from '../runJest';
 
 const DIR = path.resolve(tmpdir(), 'multi-project-runner-test');
 
@@ -509,14 +509,7 @@ describe("doesn't bleed module file extensions resolution with multiple workers"
       };`,
     });
 
-    const {stdout: configOutput} = runJest(DIR, [
-      '--show-config',
-      '--projects',
-      'project1',
-      'project2',
-    ]);
-
-    const {configs} = JSON.parse(configOutput);
+    const {configs} = getConfig(DIR, ['--projects', 'project1', 'project2']);
 
     expect(configs).toHaveLength(2);
 
@@ -559,9 +552,7 @@ describe("doesn't bleed module file extensions resolution with multiple workers"
     `,
     });
 
-    const {stdout: configOutput} = runJest(DIR, ['--show-config']);
-
-    const {configs} = JSON.parse(configOutput);
+    const {configs} = getConfig(DIR);
 
     expect(configs).toHaveLength(2);
 

e2e/runJest.ts

@@ -10,6 +10,7 @@ import * as path from 'path';
 import * as fs from 'fs';
 import {Writable} from 'stream';
 import execa = require('execa');
+import type {Config} from '@jest/types';
 import type {FormattedTestResults} from '@jest/test-result';
 import stripAnsi = require('strip-ansi');
 import {normalizeIcons} from './Utils';
@@ -214,3 +215,24 @@ export const runContinuous = function (
     },
   };
 };
+
+// return type matches output of logDebugMessages
+export function getConfig(
+  dir: string,
+  args: Array<string> = [],
+  options?: RunJestOptions,
+): {
+  globalConfig: Config.GlobalConfig;
+  configs: Array<Config.ProjectConfig>;
+  version: string;
+} {
+  const {exitCode, stdout} = runJest(
+    dir,
+    args.concat('--show-config'),
+    options,
+  );
+
+  expect(exitCode).toBe(0);
+
+  return JSON.parse(stdout);
+}

packages/jest-core/src/lib/log_debug_messages.ts

@@ -9,6 +9,7 @@ import type {Config} from '@jest/types';
 
 const VERSION = require('../../package.json').version;
 
+// if the output here changes, update `getConfig` in e2e/runJest.ts
 export default function logDebugMessages(
   globalConfig: Config.GlobalConfig,
   configs: Array<Config.ProjectConfig> | Config.ProjectConfig,

packages/test-utils/src/ConditionalTest.ts

@@ -41,12 +41,15 @@ export function onNodeVersions(
   versionRange: string,
   testBody: () => void,
 ): void {
+  const description = `on node ${versionRange}`;
   if (!semver.satisfies(process.versions.node, versionRange)) {
-    describe.skip(`[SKIP] tests that require node ${versionRange}`, () => {
+    describe.skip(description, () => {
       testBody();
     });
   } else {
-    testBody();
+    describe(description, () => {
+      testBody();
+    });
   }
 }