Issue #3322917 by tedbow, yash.rode, Wim Leers, narendraR: Create a test (or...

Issue #3322917 by tedbow, yash.rode, Wim Leers, narendraR: Create a test (or tests) to prove Package Manager works with submodules as implemented by packages.drupal.org

package_manager/tests/fixtures/build_test_projects/main_module/composer.json

+{
+  "name": "drupal/main_module",
+  "type": "drupal-module",
+  "version": "1.0.0"
+}

package_manager/tests/fixtures/build_test_projects/main_module/main_module.info.yml.hide

+name: Main module
+type: module
+core_version_requirement: ^9 || ^10
+project: main_module
+

package_manager/tests/fixtures/build_test_projects/main_module/main_module_submodule/main_module_submodule.info.yml.hide

+name: Main Module Submodule
+type: module
+core_version_requirement: ^9 || ^10
+project: main_module

package_manager/tests/fixtures/path_repos/main_module_submodule/composer.json

+{
+  "name": "drupal/main_module_submodule",
+  "type": "metapackage",
+  "version": "1.0.0",
+  "require": {
+    "drupal/main_module": "*"
+  }
+}

package_manager/tests/fixtures/release-history/main_module.1.0.0.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!--
+This fixture is used by \Drupal\Tests\package_manager\Build\PackageInstallTest.
+
+Contains metadata about the following (fake) releases of main_module, all of which are secure, in order:
+- 1.0.0
+-->
+<project xmlns:dc="http://purl.org/dc/elements/1.1/">
+<title>Main Module</title>
+<short_name>main_module</short_name>
+<dc:creator>Drupal</dc:creator>
+<supported_branches>1.0.</supported_branches>
+<project_status>published</project_status>
+<link>http://example.com/project/main_module</link>
+  <terms>
+   <term><name>Projects</name><value>Main Module project</value></term>
+  </terms>
+<releases>
+  <release>
+    <name>Main Module 1.0.0</name>
+    <version>1.0.0</version>
+    <tag>1.0.0</tag>
+    <status>published</status>
+    <release_link>http://example.com/main_module-1-0-0-release</release_link>
+    <download_link>http://example.com/main_module-1-0-0.tar.gz</download_link>
+    <date>1584195300</date>
+    <terms>
+      <term><name>Release type</name><value>New features</value></term>
+      <term><name>Release type</name><value>Bug fixes</value></term>
+    </terms>
+  </release>
+</releases>
+</project>

package_manager/tests/src/Build/PackageInstallTest.php

@@ -44,4 +44,47 @@ class PackageInstallTest extends TemplateProjectTestBase {
     $this->assertAppliedChangesWereLogged(['Installed drupal/alpha 1.0.0']);
   }
 
+  /**
+   * Tests installing a Drupal submodule.
+   *
+   * This test installs a submodule using a set-up that mimics how
+   * packages.drupal.org handles submodules. Submodules are Composer
+   * metapackages which depend on the Composer package of the main module.
+   */
+  public function testSubModules(): void {
+    $this->createTestProject('RecommendedProject');
+    // Set up the release metadata for the main module. The submodule does not
+    // have its own release metadata.
+    $this->setReleaseMetadata([
+      'main_module' => __DIR__ . '/../../fixtures/release-history/main_module.1.0.0.xml',
+    ]);
+
+    // Add repositories for Drupal modules which will contain the code for its
+    // submodule also.
+    $this->addRepository('main_module', $this->copyFixtureToTempDirectory(__DIR__ . '/../../fixtures/build_test_projects/main_module'));
+
+    // Add a repository for the submodule of 'main_module'. Submodule
+    // repositories are metapackages which have no code of their own but that
+    // require the main module.
+    $this->addRepository('main_module_submodule', $this->copyFixtureToTempDirectory(__DIR__ . '/../../fixtures/path_repos/main_module_submodule'));
+
+    // Repository definitions affect the lock file hash, so update the hash to
+    // ensure that Composer won't complain that the lock file is out of sync.
+    $this->runComposer('composer update --lock', 'project');
+
+    $this->makePackageManagerTestApiRequest(
+      '/package-manager-test-api',
+      [
+        'runtime' => [
+          'drupal/main_module_submodule:1.0.0',
+        ],
+      ]
+    );
+
+    // Assert main_module and the submodule were installed.
+    $main_module_path = $this->getWebRoot() . '/modules/contrib/main_module';
+    $this->assertFileExists("$main_module_path/main_module.info.yml");
+    $this->assertFileExists("$main_module_path/main_module_submodule/main_module_submodule.info.yml");
+  }
+
 }