Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/tests/Drupal/Tests/ComposerIntegrationTest.php

@@ -0,0 +1,71 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\ComposerIntegrationTest.
+ */
+
+namespace Drupal\Tests;
+
+/**
+ * Tests Composer integration.
+ *
+ * @group Composer
+ */
+class ComposerIntegrationTest extends UnitTestCase {
+
+  /**
+   * Gets human-readable JSON error messages.
+   *
+   * @return string[]
+   *   Keys are JSON_ERROR_* constants.
+   */
+  protected function getErrorMessages() {
+    $messages = [
+      JSON_ERROR_DEPTH => 'The maximum stack depth has been exceeded',
+      JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON',
+      JSON_ERROR_CTRL_CHAR => 'Control character error, possibly incorrectly encoded',
+      JSON_ERROR_SYNTAX => 'Syntax error',
+      JSON_ERROR_UTF8 => 'Malformed UTF-8 characters, possibly incorrectly encoded',
+    ];
+
+    if (version_compare(phpversion(), '5.5.0', '>=')) {
+      $messages[JSON_ERROR_RECURSION] = 'One or more recursive references in the value to be encoded';
+      $messages[JSON_ERROR_INF_OR_NAN] = 'One or more NAN or INF values in the value to be encoded';
+      $messages[JSON_ERROR_UNSUPPORTED_TYPE] = 'A value of a type that cannot be encoded was given';
+    }
+
+    return $messages;
+  }
+
+  /**
+   * Gets the paths to the folders that contain the Composer integration.
+   *
+   * @return string[]
+   *   The paths.
+   */
+  protected function getPaths() {
+    return [
+      $this->root,
+      $this->root . '/core',
+      $this->root . '/core/lib/Drupal/Component/Plugin',
+      $this->root . '/core/lib/Drupal/Component/ProxyBuilder',
+      $this->root . '/core/lib/Drupal/Component/Utility',
+    ];
+  }
+
+  /**
+   * Tests composer.json.
+   */
+  public function testComposerJson() {
+    foreach ($this->getPaths() as $path) {
+      $json = file_get_contents($path . '/composer.json');
+
+      $result = json_decode($json);
+      if (is_null($result)) {
+        $this->fail($this->getErrorMessages()[json_last_error()]);
+      }
+    }
+  }
+
+}