Fix.

node_modules/jest-runtime/build/helpers.js

@@ -0,0 +1,92 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.findSiblingsWithFileExtension = void 0;
+
+function _path() {
+  const data = _interopRequireDefault(require('path'));
+
+  _path = function _path() {
+    return data;
+  };
+
+  return data;
+}
+
+function _slash() {
+  const data = _interopRequireDefault(require('slash'));
+
+  _slash = function _slash() {
+    return data;
+  };
+
+  return data;
+}
+
+function _glob() {
+  const data = _interopRequireDefault(require('glob'));
+
+  _glob = function _glob() {
+    return data;
+  };
+
+  return data;
+}
+
+function _interopRequireDefault(obj) {
+  return obj && obj.__esModule ? obj : {default: obj};
+}
+
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+const findSiblingsWithFileExtension = (
+  moduleFileExtensions,
+  from,
+  moduleName
+) => {
+  if (
+    !_path().default.isAbsolute(moduleName) &&
+    _path().default.extname(moduleName) === ''
+  ) {
+    const dirname = _path().default.dirname(from);
+
+    const pathToModule = _path().default.resolve(dirname, moduleName);
+
+    try {
+      const slashedDirname = (0, _slash().default)(dirname);
+
+      const matches = _glob()
+        .default.sync(`${pathToModule}.*`)
+        .map(match => (0, _slash().default)(match))
+        .map(match => {
+          const relativePath = _path().default.posix.relative(
+            slashedDirname,
+            match
+          );
+
+          return _path().default.posix.dirname(match) === slashedDirname
+            ? `./${relativePath}`
+            : relativePath;
+        })
+        .map(match => `\t'${match}'`)
+        .join('\n');
+
+      if (matches) {
+        const foundMessage = `\n\nHowever, Jest was able to find:\n${matches}`;
+        const mappedModuleFileExtensions = moduleFileExtensions
+          .map(ext => `'${ext}'`)
+          .join(', ');
+        return (
+          foundMessage +
+          "\n\nYou might want to include a file extension in your import, or update your 'moduleFileExtensions', which is currently " +
+          `[${mappedModuleFileExtensions}].\n\nSee https://jestjs.io/docs/en/configuration#modulefileextensions-array-string`
+        );
+      }
+    } catch (ignored) {}
+  }
+
+  return '';
+};
+
+exports.findSiblingsWithFileExtension = findSiblingsWithFileExtension;