feat: support . in exports field (#11919)

Author: SimenB

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### Features
 
 - `[jest-config]` Add `testEnvironmentOptions.html` to apply to jsdom input ([11950](https://github.com/facebook/jest/pull/11950))
+- `[jest-resolver]` Support default export (`.`) in `exports` field _if_ `main` is missing ([#11919](https://github.com/facebook/jest/pull/11919))
 
 ### Fixes
 

e2e/__tests__/resolveConditions.test.ts

@@ -7,15 +7,10 @@
 
 import {resolve} from 'path';
 import {onNodeVersions} from '@jest/test-utils';
-import {runYarnInstall} from '../Utils';
 import runJest from '../runJest';
 
 const dir = resolve(__dirname, '..', 'resolve-conditions');
 
-beforeAll(() => {
- runYarnInstall(dir);
-});
-
 // The versions where vm.Module exists and commonjs with "exports" is not broken
 onNodeVersions('>=12.16.0', () => {
  test('resolves package exports correctly with custom resolver', () => {

e2e/resolve-conditions/__tests__/browser.test.mjs

@@ -7,7 +7,7 @@
  * @jest-environment <rootDir>/browser-env.js
  */
 
-import {fn} from '../fake-dual-dep';
+import {fn} from 'fake-dual-dep';
 
 test('returns correct message', () => {
  expect(fn()).toEqual('hello from browser');

e2e/resolve-conditions/__tests__/node.test.mjs

@@ -7,7 +7,7 @@
  * @jest-environment <rootDir>/node-env.js
  */
 
-import {fn} from '../fake-dual-dep';
+import {fn} from 'fake-dual-dep';
 
 test('returns correct message', () => {
  expect(fn()).toEqual('hello from node');

e2e/resolve-conditions/__tests__/resolveCjs.test.cjs

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-const {fn} = require('../fake-dep');
+const {fn} = require('fake-dep');
 
 test('returns correct message', () => {
  expect(fn()).toEqual('hello from CJS');

e2e/resolve-conditions/__tests__/resolveEsm.test.mjs

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {fn} from '../fake-dep';
+import {fn} from 'fake-dep';
 
 test('returns correct message', () => {
  expect(fn()).toEqual('hello from ESM');