Improve test coverage for Optimization Detective

plugins/optimization-detective/class-od-link-collection.php

@@ -114,12 +114,18 @@ public function add_link( array $attributes, ?int $minimum_viewport_width = null
 	 * @return LinkAttributes[] Prepared links with adjacent-duplicates merged together and media attributes added.
 	 */
 	private function get_prepared_links(): array {
+		$links_by_rel = array_values( $this->links_by_rel );
+		if ( count( $links_by_rel ) === 0 ) {
+			// This condition is needed for PHP 7.2 and PHP 7.3 in which array_merge() fails if passed a spread empty array: 'array_merge() expects at least 1 parameter, 0 given'.
+			return array();
+		}
+
 		return array_merge(
 			...array_map(
 				function ( array $links ): array {
 					return $this->merge_consecutive_links( $links );
 				},
-				array_values( $this->links_by_rel )
+				$links_by_rel
 			)
 		);
 	}

plugins/optimization-detective/class-od-strict-url-metric.php

@@ -18,6 +18,8 @@
  * This is used exclusively in the REST API endpoint for capturing new URL Metrics to prevent invalid additional data from being
  * submitted in the request. For URL Metrics which have been stored the looser OD_URL_Metric class is used instead.
  *
+ * @phpstan-import-type JSONSchema from OD_URL_Metric
+ *
  * @since 0.6.0
  * @access private
  */
@@ -28,7 +30,7 @@
 	 *
 	 * @since 0.6.0
 	 *
-	 * @return array<string, mixed> Schema.
+	 * @return JSONSchema Schema.
 	 */
 	public static function get_json_schema(): array {
 		return self::set_additional_properties_to_false( parent::get_json_schema() );
@@ -43,34 +45,36 @@
 	 * @since 0.6.0
 	 * @see rest_default_additional_properties_to_false()
 	 *
-	 * @param mixed $schema Schema.
-	 * @return mixed Processed schema.
+	 * @phpstan-param JSONSchema $schema
+	 *
+	 * @param array<string, mixed> $schema Schema.
+	 * @return JSONSchema Processed schema.
 	 */
-	private static function set_additional_properties_to_false( $schema ) {
-		if ( ! isset( $schema['type'] ) ) {
-			return $schema;
-		}
-
+	private static function set_additional_properties_to_false( array $schema ): array {
 		$type = (array) $schema['type'];
 
 		if ( in_array( 'object', $type, true ) ) {
 			if ( isset( $schema['properties'] ) ) {
 				foreach ( $schema['properties'] as $key => $child_schema ) {
-					$schema['properties'][ $key ] = self::set_additional_properties_to_false( $child_schema );
+					if ( isset( $child_schema['type'] ) ) {
+						$schema['properties'][ $key ] = self::set_additional_properties_to_false( $child_schema );
+					}
 				}
 			}
 
 			if ( isset( $schema['patternProperties'] ) ) {
 				foreach ( $schema['patternProperties'] as $key => $child_schema ) {
-					$schema['patternProperties'][ $key ] = self::set_additional_properties_to_false( $child_schema );
+					if ( isset( $child_schema['type'] ) ) {
+						$schema['patternProperties'][ $key ] = self::set_additional_properties_to_false( $child_schema );
+					}
 				}
 			}
 
 			$schema['additionalProperties'] = false;
 		}
 
 		if ( in_array( 'array', $type, true ) ) {
-			if ( isset( $schema['items'] ) ) {
+			if ( isset( $schema['items'], $schema['items']['type'] ) ) {
 				$schema['items'] = self::set_additional_properties_to_false( $schema['items'] );
 			}
 		}

plugins/optimization-detective/class-od-url-metric-group-collection.php

@@ -271,9 +271,12 @@ public function add_url_metric( OD_URL_Metric $new_url_metric ): void {
 				return;
 			}
 		}
+		// @codeCoverageIgnoreStart
+		// In practice this exception should never get thrown because create_groups() creates groups from a minimum of 0 to a maximum of PHP_INT_MAX.
 		throw new InvalidArgumentException(
 			esc_html__( 'No group available to add URL Metric to.', 'optimization-detective' )
 		);
+		// @codeCoverageIgnoreEnd
 	}
 
 	/**
@@ -296,6 +299,8 @@ public function get_group_for_viewport_width( int $viewport_width ): OD_URL_Metr
 					return $group;
 				}
 			}
+			// @codeCoverageIgnoreStart
+			// In practice this exception should never get thrown because create_groups() creates groups from a minimum of 0 to a maximum of PHP_INT_MAX.
 			throw new InvalidArgumentException(
 				esc_html(
 					sprintf(
@@ -305,6 +310,7 @@ public function get_group_for_viewport_width( int $viewport_width ): OD_URL_Metr
 					)
 				)
 			);
+			// @codeCoverageIgnoreEnd
 		} )();
 
 		$this->result_cache[ __FUNCTION__ ][ $viewport_width ] = $result;

plugins/optimization-detective/class-od-url-metric.php

@@ -45,6 +45,19 @@
  *                                viewport: ViewportRect,
  *                                elements: ElementData[]
  *                            }
+ * @phpstan-type JSONSchema   array{
+ *                                type: string|string[],
+ *                                items?: mixed,
+ *                                properties?: array<string, mixed>,
+ *                                patternProperties?: array<string, mixed>,
+ *                                required?: bool,
+ *                                minimum?: int,
+ *                                maximum?: int,
+ *                                pattern?: non-empty-string,
+ *                                additionalProperties?: bool,
+ *                                format?: non-empty-string,
+ *                                readonly?: bool,
+ *                            }
  *
  * @since 0.1.0
  * @access private
@@ -161,7 +174,7 @@ public function set_group( OD_URL_Metric_Group $group ): void {
 	 *
 	 * @todo Cache the return value?
 	 *
-	 * @return array<string, mixed> Schema.
+	 * @return JSONSchema Schema.
 	 */
 	public static function get_json_schema(): array {
 		/*

plugins/optimization-detective/hooks.php

@@ -12,6 +12,9 @@
 }
 // @codeCoverageIgnoreEnd
 
+// The addition of the following hooks is tested in Test_OD_Hooks::test_hooks_added() and Test_OD_Storage_Post_Type::test_add_hooks().
+
+// @codeCoverageIgnoreStart
 add_action( 'init', 'od_initialize_extensions', PHP_INT_MAX );
 add_filter( 'template_include', 'od_buffer_output', PHP_INT_MAX );
 OD_URL_Metrics_Post_Type::add_hooks();
@@ -20,3 +23,4 @@
 add_filter( 'site_status_tests', 'od_add_rest_api_availability_test' );
 add_action( 'admin_init', 'od_maybe_run_rest_api_health_check' );
 add_action( 'after_plugin_row_meta', 'od_render_rest_api_health_check_admin_notice_in_plugin_row', 30 );
+// @codeCoverageIgnoreEnd

plugins/optimization-detective/storage/rest-api.php

@@ -168,7 +168,7 @@ function od_handle_rest_request( WP_REST_Request $request ) {
 		);
 	} catch ( InvalidArgumentException $exception ) {
 		// Note: This should never happen because an exception only occurs if a viewport width is less than zero, and the JSON Schema enforces that the viewport.width have a minimum of zero.
-		return new WP_Error( 'invalid_viewport_width', $exception->getMessage() );
+		return new WP_Error( 'invalid_viewport_width', $exception->getMessage() ); // @codeCoverageIgnore
 	}
 	if ( $url_metric_group->is_complete() ) {
 		return new WP_Error(
@@ -279,7 +279,7 @@ function od_handle_rest_request( WP_REST_Request $request ) {
  * @since 0.8.0
  * @access private
  *
- * @param int $cache_purge_post_id Cache purge post ID.
+ * @param positive-int $cache_purge_post_id Cache purge post ID.
  */
 function od_trigger_page_cache_invalidation( int $cache_purge_post_id ): void {
 	$post = get_post( $cache_purge_post_id );

plugins/optimization-detective/tests/storage/test-rest-api.php

@@ -75,6 +75,8 @@ static function ( array $properties ) use ( $property_name ): array {
 	 * @covers ::od_register_endpoint
 	 * @covers ::od_handle_rest_request
 	 * @covers ::od_trigger_page_cache_invalidation
+	 * @covers OD_Strict_URL_Metric::set_additional_properties_to_false
+	 * @covers OD_URL_Metric_Store_Request_Context::__construct
 	 */
 	public function test_rest_request_good_params( Closure $set_up ): void {
 		$stored_context = null;
@@ -137,6 +139,28 @@ function ( OD_URL_Metric_Store_Request_Context $context ) use ( &$stored_context
 		}
 	}
 
+	/**
+	 * Test good params.
+	 *
+	 * @dataProvider data_provider_to_test_rest_request_good_params
+	 *
+	 * @covers ::od_register_endpoint
+	 * @covers ::od_handle_rest_request
+	 * @covers OD_Strict_URL_Metric::set_additional_properties_to_false
+	 */
+	public function test_rest_request_good_params_but_post_save_failed( Closure $set_up ): void {
+		$valid_params = $set_up();
+
+		add_filter( 'wp_insert_post_empty_content', '__return_true' ); // Cause wp_insert_post() to return WP_Error.
+
+		$request  = $this->create_request( $valid_params );
+		$response = rest_get_server()->dispatch( $request );
+
+		$error = $response->as_error();
+		$this->assertInstanceOf( WP_Error::class, $error );
+		$this->assertSame( 'unable_to_store_url_metric', $error->get_error_code() );
+	}
+
 	/**
 	 * Data provider for test_rest_request_bad_params.
 	 *
@@ -271,6 +295,7 @@ static function ( $params ) use ( $valid_params ) {
 	 *
 	 * @covers ::od_register_endpoint
 	 * @covers ::od_handle_rest_request
+	 * @covers OD_Strict_URL_Metric::set_additional_properties_to_false
 	 *
 	 * @dataProvider data_provider_invalid_params
 	 *
@@ -652,6 +677,22 @@ static function ( string $hook, ...$args ) use ( &$all_hook_callback_args ): voi
 		$this->assertTrue( $found, 'Expected save_post to have been fired for the post queried object.' );
 	}
 
+	/**
+	 * Test od_trigger_page_cache_invalidation() for an invalid post.
+	 *
+	 * @covers ::od_trigger_page_cache_invalidation
+	 */
+	public function test_od_trigger_page_cache_invalidation_invalid_post_id(): void {
+		wp_delete_post( 1, true );
+		$before_clean_post_cache_count       = did_action( 'clean_post_cache' );
+		$before_transition_post_status_count = did_action( 'transition_post_status' );
+		$before_save_post_count              = did_action( 'save_post' );
+		od_trigger_page_cache_invalidation( 1 );
+		$this->assertSame( $before_clean_post_cache_count, did_action( 'clean_post_cache' ) );
+		$this->assertSame( $before_transition_post_status_count, did_action( 'transition_post_status' ) );
+		$this->assertSame( $before_save_post_count, did_action( 'save_post' ) );
+	}
+
 	/**
 	 * Populate URL Metrics.
 	 *

plugins/optimization-detective/tests/test-cases/preload-link/buffer.html

@@ -0,0 +1,11 @@
+<html lang="en">
+	<head>
+		<meta charset="utf-8">
+		<title>...</title>
+	</head>
+	<body>
+		<div id="page">
+			<img src="https://example.com/image.jpg" alt="" width="100" height="100">
+		</div>
+	</body>
+</html>

plugins/optimization-detective/tests/test-cases/preload-link/set-up.php

@@ -0,0 +1,24 @@
+<?php
+return static function (): void {
+
+	add_action(
+		'od_register_tag_visitors',
+		static function ( OD_Tag_Visitor_Registry $registry ): void {
+			$registry->register(
+				'img-preload',
+				static function ( OD_Tag_Visitor_Context $context ): bool {
+					if ( 'IMG' === $context->processor->get_tag() ) {
+						$context->link_collection->add_link(
+							array(
+								'rel'  => 'preload',
+								'as'   => 'image',
+								'href' => $context->processor->get_attribute( 'src' ),
+							)
+						);
+					}
+					return false;
+				}
+			);
+		}
+	);
+};

plugins/optimization-detective/tests/test-class-od-element.php

@@ -12,6 +12,7 @@ class Test_OD_Element extends WP_UnitTestCase {
 	/**
 	 * Tests construction.
 	 *
+	 * @covers ::__construct
 	 * @covers ::get
 	 * @covers ::get_url_metric
 	 * @covers ::get_url_metric_group