diff --git a/core/tests/Drupal/Tests/ComposerIntegrationTest.php b/core/tests/Drupal/Tests/ComposerIntegrationTest.php
index 80a18b6513..c01ca25070 100644
--- a/core/tests/Drupal/Tests/ComposerIntegrationTest.php
+++ b/core/tests/Drupal/Tests/ComposerIntegrationTest.php
@@ -86,7 +86,7 @@ public function testComposerJson() {
   public function testComposerLockHash() {
     $json = file_get_contents($this->root . '/composer.json');
     $lock = json_decode(file_get_contents($this->root . '/composer.lock'), TRUE);
-    $this->assertSame(md5($json), $lock['hash']);
+    $this->assertSame(self::getContentHash($json), $lock['content-hash']);
   }
 
   /**
@@ -126,4 +126,44 @@ public function testAllModulesReplaced() {
     }
   }
 
+  /**
+   * Returns the md5 hash of the sorted content of the composer file.
+   *
+   * Note that this is a near copy-paste of
+   * \Composer\Package\Locker::getContentHash() from the Composer package.
+   *
+   * @param string $composerFileContents
+   *   The contents of the composer file.
+   *
+   * @return string
+   *   Hash of the contents of the composer file.
+   *
+   * @see https://github.com/composer/composer/blob/1.3/src/Composer/Package/Locker.php
+   */
+  private static function getContentHash($composerFileContents) {
+    $content = json_decode($composerFileContents, true);
+    $relevantKeys = array(
+      'name',
+      'version',
+      'require',
+      'require-dev',
+      'conflict',
+      'replace',
+      'provide',
+      'minimum-stability',
+      'prefer-stable',
+      'repositories',
+      'extra',
+    );
+    $relevantContent = array();
+    foreach (array_intersect($relevantKeys, array_keys($content)) as $key) {
+      $relevantContent[$key] = $content[$key];
+    }
+    if (isset($content['config']['platform'])) {
+      $relevantContent['config']['platform'] = $content['config']['platform'];
+    }
+    ksort($relevantContent);
+    return md5(json_encode($relevantContent));
+  }
+
 }