diff --git a/tests/phpunit/tests/theme/base.php b/tests/phpunit/tests/theme/base.php
index 182efa5df81e4..4c42fa3363b0a 100644
--- a/tests/phpunit/tests/theme/base.php
+++ b/tests/phpunit/tests/theme/base.php
@@ -44,6 +44,7 @@ public function tear_down() {
 		remove_filter( 'template_root', array( $this, 'filter_set_theme_root' ) );
 
 		wp_clean_themes_cache();
+		wp_clean_theme_json_cache();
 		unset( $GLOBALS['wp_themes'] );
 
 		parent::tear_down();
diff --git a/tests/phpunit/tests/theme/wpAddGlobalStylesForBlocks.php b/tests/phpunit/tests/theme/wpAddGlobalStylesForBlocks.php
index 9814a6ae68c0a..7d34e8d2a6b33 100644
--- a/tests/phpunit/tests/theme/wpAddGlobalStylesForBlocks.php
+++ b/tests/phpunit/tests/theme/wpAddGlobalStylesForBlocks.php
@@ -131,6 +131,7 @@ public function test_third_party_blocks_inline_styles_get_rendered_when_per_bloc
 	 * @ticket 61165
 	 */
 	public function test_blocks_inline_styles_get_rendered() {
+		$this->set_up_third_party_block();
 		wp_register_style( 'global-styles', false, array(), true, true );
 		wp_enqueue_style( 'global-styles' );
 		wp_add_global_styles_for_blocks();
@@ -174,6 +175,7 @@ public function test_third_party_blocks_inline_styles_for_elements_get_rendered_
 	 * @ticket 61165
 	 */
 	public function test_third_party_blocks_inline_styles_for_elements_get_rendered() {
+		$this->set_up_third_party_block();
 		wp_register_style( 'global-styles', false, array(), true, true );
 		wp_enqueue_style( 'global-styles' );
 		wp_add_global_styles_for_blocks();