Build/Test Tools: Preserve plugin query vars between tests

tests/phpunit/includes/abstract-testcase.php

@@ -183,6 +183,10 @@ public function tear_down() {
 		$wp_query     = $wp_the_query;
 		$wp           = new WP();
 
+		if ( isset( $GLOBALS['_wp_tests_initial_public_query_vars'] ) ) {
+			$wp->public_query_vars = $GLOBALS['_wp_tests_initial_public_query_vars'];
+		}
+
 		// Reset globals related to the post loop and `setup_postdata()`.
 		$post_globals = array( 'post', 'id', 'authordata', 'currentday', 'currentmonth', 'page', 'pages', 'multipage', 'more', 'numpages' );
 		foreach ( $post_globals as $global ) {

tests/phpunit/includes/bootstrap.php

@@ -299,6 +299,15 @@ function wp_tests_options( $value ) {
 
 // Load WordPress.
 require_once ABSPATH . 'wp-settings.php';
+/*
+ * Preserve public query variables registered by plugins during bootstrap.
+ *
+ * Core tests reset these variables between tests, while plugin tests expect
+ * registrations made on `init` to remain available throughout the test run.
+ */
+if ( ! defined( 'WP_RUN_CORE_TESTS' ) || ! WP_RUN_CORE_TESTS ) {
+	$GLOBALS['_wp_tests_initial_public_query_vars'] = $GLOBALS['wp']->public_query_vars;
+}
 
 // Override the PHPMailer.
 require_once __DIR__ . '/mock-mailer.php';

tests/phpunit/tests/rewrite/addRewriteEndpoint.php

@@ -47,6 +47,48 @@ public function test_should_register_query_using_query_var_param_if_not_null() {
 		$this->assertContains( 'bar', $GLOBALS['wp']->public_query_vars );
 	}
 
+	/**
+	 * Sets up the non-core test-suite state before the test case is torn down.
+	 *
+	 * @ticket 37207
+	 *
+	 * @return array{exists: bool, value: string[]|null} Previous global state.
+	 */
+	public function test_should_preserve_query_vars_registered_during_plugin_bootstrap() {
+		$previous_state = array(
+			'exists' => isset( $GLOBALS['_wp_tests_initial_public_query_vars'] ),
+			'value'  => $GLOBALS['_wp_tests_initial_public_query_vars'] ?? null,
+		);
+
+		add_rewrite_endpoint( 'plugin-endpoint', EP_ROOT );
+		$this->assertContains( 'plugin-endpoint', $GLOBALS['wp']->public_query_vars );
+
+		$GLOBALS['_wp_tests_initial_public_query_vars'] = $GLOBALS['wp']->public_query_vars;
+
+		return $previous_state;
+	}
+
+	/**
+	 * Verifies the query variables after the preceding test's tear down.
+	 *
+	 * @ticket 37207
+	 *
+	 * @depends test_should_preserve_query_vars_registered_during_plugin_bootstrap
+	 *
+	 * @param array{exists: bool, value: string[]|null} $previous_state Previous global state.
+	 */
+	public function test_should_restore_query_vars_registered_during_plugin_bootstrap( $previous_state ) {
+		try {
+			$this->assertContains( 'plugin-endpoint', $GLOBALS['wp']->public_query_vars );
+		} finally {
+			if ( $previous_state['exists'] ) {
+				$GLOBALS['_wp_tests_initial_public_query_vars'] = $previous_state['value'];
+			} else {
+				unset( $GLOBALS['_wp_tests_initial_public_query_vars'] );
+			}
+		}
+	}
+
 	/**
 	 * @ticket 25143
 	 */