3442351: Adding initial testing.

Closes #3442351

tests/src/Functional/JsonApiPermissionAccessTest.php

+<?php
+
+namespace Drupal\Tests\jsonapi_permission_access\JsonApiPermissionAccessTest;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Testing JSON:API Permission Access.
+ *
+ * @group jsonapi_permission_access
+ */
+class JsonApiPermissionAccessTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'node',
+    'jsonapi',
+    'serialization',
+    'jsonapi_permission_access',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Setup function.
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    // Create an article content type for testing.
+    $this->drupalCreateContentType([
+      'type' => 'article',
+      'name' => 'Article',
+    ]);
+
+    // Create article which will have NID.
+    $this->drupalCreateNode([
+      'type' => 'article',
+      'title' => 'Article for testing.',
+    ]);
+
+    $this->container->get('router.builder')->rebuild();
+  }
+
+  /**
+   * Tests that a 403 is returned on JSON:API routes.
+   */
+  public function testJsonApiStatusCode() {
+    $account = $this->drupalCreateUser(['access content']);
+    $this->drupalLogin($account);
+    $this->drupalGet('jsonapi/node/article');
+    $this->assertSession()->statusCodeEquals(403);
+  }
+
+  /**
+   * Tests that a user with the correct permission can access.
+   */
+  public function testUserAccessWithPermission() {
+    $account = $this->drupalCreateUser(['access jsonapi routes']);
+    $this->drupalLogin($account);
+    $this->drupalGet('jsonapi/node/article');
+    $this->assertSession()->statusCodeEquals(200);
+  }
+
+}