Issue #3176561 by beram: Add a test for block plugin cache metadata

tests/src/Kernel/AccessTest.php

@@ -319,7 +319,7 @@ class AccessTest extends KernelTestBase {
     self::assertSame($expected_content, $build['content']);
     $expected_cache = [
       'contexts' => ['user'],
-      'tags' => ['tag_from_blockAccess'],
+      'tags' => ['tag_from_blockAccess', 'tag_twig_tweak_test_foo_plugin'],
       'max-age' => 35,
     ];
     self::assertSame($expected_cache, $build['#cache']);

tests/twig_tweak_test/src/Plugin/Block/FooBlock.php

@@ -41,4 +41,11 @@ class FooBlock extends BlockBase {
     ];
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheTags() {
+    return ['tag_twig_tweak_test_foo_plugin'];
+  }
+
 }