Issue #3318313: Make OverwriteExistingPackagesValidatorTest fixture less

package_manager/tests/src/Kernel/OverwriteExistingPackagesValidatorTest.php

@@ -33,19 +33,7 @@ class OverwriteExistingPackagesValidatorTest extends PackageManagerKernelTestBas
    * managed by Composer.
    *
    * The staging area has four modules: module_1, module_2, module_3, and
-   * module_5_different_path. All of them are managed by Composer. We expect the
-   * following outcomes:
-   *
-   * - module_1 and module_2 will raise errors because they would overwrite
-   *   non-Composer managed paths in the active directory.
-   * - module_3 will cause no problems, since it doesn't exist in the active
-   *   directory at all.
-   * - module_4, which is defined only in the staged installed.json and
-   *   installed.php, will cause an error because its path collides with
-   *   module_1.
-   * - module_5_different_path will not cause a problem, even though its package
-   *   name is drupal/module_5, because its project name and path in the staging
-   *   area differ from the active directory.
+   * module_5_different_path. All of them are managed by Composer.
    */
   public function testNewPackagesOverwriteExisting(): void {
     $fixtures_dir = __DIR__ . '/../../fixtures/overwrite_existing_validation';
@@ -54,6 +42,9 @@ class OverwriteExistingPackagesValidatorTest extends PackageManagerKernelTestBas
     $stage = $this->createStage();
     $stage->create();
     $stage_dir = $stage->getStageDirectory();
+
+    // module_1 and module_2 will raise errors because they would overwrite
+    // non-Composer managed paths in the active directory.
     $this->addPackage($stage_dir, [
       'name' => 'drupal/module_1',
       'version' => '1.3.0',
@@ -66,18 +57,28 @@ class OverwriteExistingPackagesValidatorTest extends PackageManagerKernelTestBas
       'type' => 'drupal-module',
       'install_path' => '../../modules/module_2',
     ]);
+
+    // module_3 will cause no problems, since it doesn't exist in the active
+    // directory at all.
     $this->addPackage($stage_dir, [
       'name' => 'drupal/module_3',
       'version' => '1.3.0',
       'type' => 'drupal-module',
       'install_path' => '../../modules/module_3',
     ]);
+
+    // module_4, doesn't exist in the active directory but exists in the staged
+    // directory, will cause an error because its path collides with module_1.
     $this->addPackage($stage_dir, [
       'name' => 'drupal/module_4',
       'version' => '1.3.0',
       'type' => 'drupal-module',
       'install_path' => '../../modules/module_1',
     ]);
+
+    // module_5_different_path will not cause a problem, even though its package
+    // name is drupal/module_5, because its project name and path in the staging
+    // area differ from the active directory.
     $this->addPackage($stage_dir, [
       'name' => 'drupal/module_5',
       'version' => '1.3.0',