diff --git a/core/drupalci.yml b/core/drupalci.yml
index ed02d43c63..d9a9e07939 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -19,41 +19,8 @@ build:
       # halt-on-fail can be set on the run_tests tasks in order to fail fast.
       # suppress-deprecations is false in order to be alerted to usages of
       # deprecated code.
-      run_tests.phpunit:
-        types: 'PHPUnit-Unit'
-        testgroups: '--all'
-        suppress-deprecations: false
-        halt-on-fail: false
-      run_tests.kernel:
-        types: 'PHPUnit-Kernel'
-        testgroups: '--all'
-        suppress-deprecations: false
-        halt-on-fail: false
-      run_tests.simpletest:
-         types: 'Simpletest'
-         testgroups: '--all'
-         suppress-deprecations: false
-         halt-on-fail: false
       run_tests.build:
         types: 'PHPUnit-Build'
         testgroups: '--all'
         suppress-deprecations: false
         halt-on-fail: false
-      run_tests.functional:
-        types: 'PHPUnit-Functional'
-        testgroups: '--all'
-        suppress-deprecations: false
-        halt-on-fail: false
-      run_tests.javascript:
-        concurrency: 15
-        types: 'PHPUnit-FunctionalJavascript'
-        testgroups: '--all'
-        suppress-deprecations: false
-        halt-on-fail: false
-      # Run nightwatch testing.
-      # @see https://www.drupal.org/project/drupal/issues/2869825
-      nightwatchjs:
-#      container_command.drupal_project_templates:
-#        commands:
-#          - "sudo -u www-data ${SOURCE_DIR}/core/tests/scripts/test_composer_project_templates.sh"
-#        halt-on-fail: true
diff --git a/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php b/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php
index 4e00e5ad19..3ded6d55ea 100644
--- a/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php
+++ b/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php
@@ -4,6 +4,7 @@
 
 use Drupal\BuildTests\Framework\BuildTestBase;
 use org\bovigo\vfs\vfsStream;
+use Symfony\Component\Filesystem\Filesystem;
 use Symfony\Component\Finder\Finder;
 
 /**
@@ -56,8 +57,8 @@ public function testCopyCodebase() {
    * @covers ::copyCodebase
    */
   public function testCopyCodebaseExclude() {
-    // Create a virtual file system containing only items that should be
-    // excluded.
+    // Create a virtual file system containing items that should be
+    // excluded. Exception being modules directory.
     vfsStream::setup('drupal', NULL, [
       'sites' => [
         'default' => [
@@ -65,6 +66,7 @@ public function testCopyCodebaseExclude() {
             'a_file.txt' => 'some file.',
           ],
           'settings.php' => '<?php $settings = stuff;',
+          'settings.local.php' => '<?php $settings = override;',
         ],
         'simpletest' => [
           'simpletest_hash' => [
@@ -79,6 +81,15 @@ public function testCopyCodebaseExclude() {
           ],
         ],
       ],
+      'modules' => [
+        'my_module' => [
+          'vendor' => [
+            'my_vendor' => [
+              'composer.json' => "{\n}"
+            ],
+          ],
+        ],
+      ],
     ]);
 
     // Mock BuildTestBase so that it thinks our VFS is the Drupal root.
@@ -98,6 +109,13 @@ public function testCopyCodebaseExclude() {
     $full_path = $base->getWorkspaceDirectory() . '/' . $test_directory;
 
     $this->assertDirectoryExists($full_path);
+
+    // Verify nested vendor directory was not excluded. Then remove it for next
+    // validation.
+    $this->assertFileExists($full_path . DIRECTORY_SEPARATOR . 'modules/my_module/vendor/my_vendor/composer.json');
+    $file_system = new Filesystem();
+    $file_system->remove($full_path . DIRECTORY_SEPARATOR . 'modules');
+
     // Use scandir() to determine if our target directory is empty. It should
     // only contain the system dot directories.
     $this->assertTrue(