Issue #3299417 by kunal.sachdev: Add a build test to prove Package Manager can...

Issue #3299417 by kunal.sachdev: Add a build test to prove Package Manager can be used to require new packages

package_manager/tests/modules/package_manager_test_api/src/SystemChangeRecorder.php

@@ -82,6 +82,12 @@ class SystemChangeRecorder implements EventSubscriberInterface {
    *   The stage event.
    */
   public function recordSystemState(StageEvent $event): void {
+    // The rest of this method is strongly coupled to updated_module, so if it
+    // isn't installed, bail out now.
+    if (!\Drupal::moduleHandler()->moduleExists('updated_module')) {
+      return;
+    }
+
     $results = [];
 
     // Call a function in a loaded file to ensure it doesn't get reloaded after

package_manager/tests/src/Build/PackageInstallTest.php

+<?php
+
+namespace Drupal\Tests\package_manager\Build;
+
+/**
+ * Tests installing packages in a staging area.
+ *
+ * @group package_manager
+ */
+class PackageInstallTest extends TemplateProjectTestBase {
+
+  /**
+   * Tests installing packages in a staging area.
+   */
+  public function testPackageInstall(): void {
+    $this->createTestProject('RecommendedProject');
+
+    $this->addRepository('alpha', __DIR__ . '/../../fixtures/alpha/1.0.0');
+
+    $this->installQuickStart('minimal');
+    $this->formLogin($this->adminUsername, $this->adminPassword);
+    $this->installModules(['package_manager_test_api']);
+
+    // Use the API endpoint to create a stage and install alpha 1.0.0. We ask
+    // the API to return the contents of composer.json file of installed module,
+    // so we can assert that the module was installed with the expected version.
+    // @see \Drupal\package_manager_test_api\ApiController::run()
+    $query = http_build_query([
+      'runtime' => [
+        'drupal/alpha:1.0.0',
+      ],
+      'files_to_return' => [
+        'web/modules/contrib/alpha/composer.json',
+      ],
+    ]);
+    $this->visit("/package-manager-test-api?$query");
+    $mink = $this->getMink();
+    $mink->assertSession()->statusCodeEquals(200);
+
+    $file_contents = $mink->getSession()->getPage()->getContent();
+    $file_contents = json_decode($file_contents, TRUE);
+
+    $this->assertArrayHasKey('web/modules/contrib/alpha/composer.json', $file_contents);
+  }
+
+}