🏗Make babel plugin tests work with jest v25 (ampproject#28002)

build-system/tasks/babel-plugin-tests.js

@@ -15,29 +15,27 @@
  */
 'use strict';
 
-const gulp = require('gulp');
-const jest = require('gulp-jest').default;
+const jest = require('@jest/core');
 const {isTravisBuild} = require('../common/travis');
 
 /**
- * Simple wrapper around the jest tests for custom babel plugins.
- * @return {!Vinyl}
+ * Entry point for `gulp babel-plugin-tests`. Runs the jest-based tests for
+ * AMP's custom babel plugins.
  */
-function babelPluginTests() {
-  return gulp.src('./build-system/babel-plugins/testSetupFile.js').pipe(
-    jest({
-      'testRegex': '/babel-plugins/[^/]+/test/.+\\.m?js$',
-      'testPathIgnorePatterns': ['/node_modules/'],
-      'testEnvironment': 'node',
-      'transformIgnorePatterns': ['/node_modules/'],
-      'coveragePathIgnorePatterns': ['/node_modules/'],
-      'modulePathIgnorePatterns': ['/test/fixtures/', '<rootDir>/build/'],
-      'reporters': [
-        isTravisBuild() ? 'jest-silent-reporter' : 'jest-dot-reporter',
-      ],
-      'automock': false,
-    })
-  );
+async function babelPluginTests() {
+  const projects = ['./build-system/babel-plugins'];
+  const options = {
+    automock: false,
+    coveragePathIgnorePatterns: ['/node_modules/'],
+    modulePathIgnorePatterns: ['/test/fixtures/', '<rootDir>/build/'],
+    reporters: [isTravisBuild() ? 'jest-silent-reporter' : 'jest-dot-reporter'],
+    setupFiles: ['./build-system/babel-plugins/testSetupFile.js'],
+    testEnvironment: 'node',
+    testPathIgnorePatterns: ['/node_modules/'],
+    testRegex: '/babel-plugins/[^/]+/test/.+\\.m?js$',
+    transformIgnorePatterns: ['/node_modules/'],
+  };
+  await jest.runCLI(options, projects);
 }
 
 module.exports = {

package.json

@@ -37,6 +37,7 @@
     "@babel/plugin-transform-react-constant-elements": "7.9.0",
     "@babel/plugin-transform-react-jsx": "7.9.4",
     "@babel/preset-env": "7.9.5",
+    "@jest/core": "25.4.0",
     "@types/minimist": "1.2.0",
     "acorn-globals": "6.0.0",
     "amphtml-validator": "1.0.30",
@@ -106,7 +107,6 @@
     "gulp-help": "chmontgomery/gulp-help#gulp4",
     "gulp-if": "3.0.0",
     "gulp-istanbul": "1.1.3",
-    "gulp-jest": "4.0.3",
     "gulp-jsonlint": "1.3.2",
     "gulp-jsonminify": "1.1.0",
     "gulp-nop": "0.0.3",
@@ -117,7 +117,6 @@
     "gulp-watch": "5.0.1",
     "gzip-size": "5.1.1",
     "html-minifier": "4.0.0",
-    "jest-cli": "24.9.0",
     "jest-dot-reporter": "1.0.12",
     "jest-silent-reporter": "0.2.1",
     "jison": "0.4.18",