From ed4edd890cf24a48b234b4ae707708c300efe4c9 Mon Sep 17 00:00:00 2001
From: Anthony Astige <astige@fb.com>
Date: Wed, 10 Jul 2019 08:20:18 -0700
Subject: [PATCH] red

---
 .../src/lib/__tests__/dependencyExtractor.test.js      | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/packages/jest-haste-map/src/lib/__tests__/dependencyExtractor.test.js b/packages/jest-haste-map/src/lib/__tests__/dependencyExtractor.test.js
index e13ed50c735f..c3e8859ab1f2 100644
--- a/packages/jest-haste-map/src/lib/__tests__/dependencyExtractor.test.js
+++ b/packages/jest-haste-map/src/lib/__tests__/dependencyExtractor.test.js
@@ -11,12 +11,22 @@ import isRegExpSupported from '../isRegExpSupported';
 const COMMENT_NO_NEG_LB = isRegExpSupported('(?<!\\.\\s*)') ? '' : '//';
 
 describe('dependencyExtractor', () => {
+  // https://github.com/facebook/jest/issues/8547
+  // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#Import_a_module_for_its_side_effects_only
+  it('should extract dependencies from side-effect only imports', () => {
+      const code = `
+        import './side-effect-dep';
+      `;
+      expect(extract(code)).toEqual(new Set(['./side-effect-dep']));
+  });
+
   it('should not extract dependencies inside comments', () => {
     const code = `
       // import a from 'ignore-line-comment';
       // require('ignore-line-comment');
       /*
        * import a from 'ignore-block-comment';
+       * import './ignore-block-comment';
        * require('ignore-block-comment');
        */
     `;