Improve Test Coverage for Speculation Rules Plugin

plugins/speculation-rules/load.php

@@ -19,7 +19,6 @@
 if ( ! defined( 'ABSPATH' ) ) {
 	exit; // Exit if accessed directly.
 }
-// @codeCoverageIgnoreEnd
 
 (
 	/**
@@ -83,3 +82,4 @@ static function ( string $version ): void {
 		require_once __DIR__ . '/settings.php';
 	}
 );
+// @codeCoverageIgnoreEnd

plugins/speculation-rules/settings.php

@@ -224,7 +224,8 @@ function plsr_render_settings_field( array $args ): void {
 			$choices = plsr_get_eagerness_labels();
 			break;
 		default:
-			return; // Invalid (and this case should never occur).
+			// Invalid (and this case should never occur).
+			return; // @codeCoverageIgnore
 	}
 
 	$value = $option[ $args['field'] ];

plugins/speculation-rules/tests/test-speculation-rules-settings.php

@@ -9,6 +9,9 @@ class Test_Speculation_Rules_Settings extends WP_UnitTestCase {
 
 	/**
 	 * @covers ::plsr_register_setting
+	 * @covers ::plsr_get_mode_labels
+	 * @covers ::plsr_get_eagerness_labels
+	 * @covers ::plsr_get_setting_default
 	 */
 	public function test_plsr_register_setting(): void {
 		unregister_setting( 'reading', 'plsr_speculation_rules' );
@@ -18,6 +21,14 @@ public function test_plsr_register_setting(): void {
 		plsr_register_setting();
 		$settings = get_registered_settings();
 		$this->assertArrayHasKey( 'plsr_speculation_rules', $settings );
+
+		$settings = plsr_get_setting_default();
+		$this->assertArrayHasKey( 'mode', $settings );
+		$this->assertArrayHasKey( 'eagerness', $settings );
+
+		// Test default settings applied correctly.
+		$default_settings = plsr_get_setting_default();
+		$this->assertEquals( $default_settings, get_option( 'plsr_speculation_rules' ) );
 	}
 
 	/**
@@ -122,4 +133,131 @@ public function test_plsr_add_settings_action_link(): void {
 			plsr_add_settings_action_link( $default_action_links )
 		);
 	}
+
+	/**
+	 * @covers ::plsr_get_stored_setting_value
+	 */
+	public function test_get_stored_setting_value(): void {
+		update_option(
+			'plsr_speculation_rules',
+			array(
+				'mode'      => 'prefetch',
+				'eagerness' => 'moderate',
+			)
+		);
+		$settings = plsr_get_stored_setting_value();
+		$this->assertEquals(
+			array(
+				'mode'      => 'prefetch',
+				'eagerness' => 'moderate',
+			),
+			$settings
+		);
+
+		// Test default when no option is set.
+		delete_option( 'plsr_speculation_rules' );
+		$settings = plsr_get_stored_setting_value();
+		$this->assertEquals( plsr_get_setting_default(), $settings );
+	}
+
+	/**
+	 * Function to test sanitize_setting() with various inputs.
+	 */
+	public function test_plsr_sanitize_setting_with_invalid_inputs(): void {
+
+		$input     = array(
+			'mode'      => 'invalid_mode',
+			'eagerness' => 'conservative',
+		);
+		$sanitized = plsr_sanitize_setting( $input );
+		$this->assertEquals( 'prerender', $sanitized['mode'] );
+
+		$input     = array(
+			'mode'      => 'prefetch',
+			'eagerness' => 'invalid_eagerness',
+		);
+		$sanitized = plsr_sanitize_setting( $input );
+		$this->assertEquals( 'moderate', $sanitized['eagerness'] );
+
+		$input     = 'invalid_input';
+		$sanitized = plsr_sanitize_setting( $input );
+		$this->assertEquals( plsr_get_setting_default(), $sanitized );
+	}
+
+	/**
+	 * @covers ::plsr_add_setting_ui
+	 */
+	public function test_plsr_add_setting_ui(): void {
+		do_action( 'load-options-reading.php' );// phpcs:ignore WordPress.NamingConventions.ValidHookName.UseUnderscores
+
+		// Check if the settings section has been added.
+		global $wp_settings_sections;
+		$this->assertArrayHasKey( 'reading', $wp_settings_sections );
+		$this->assertArrayHasKey( 'plsr_speculation_rules', $wp_settings_sections['reading'] );
+
+		// Check the output of the callback function for the section.
+		$output = get_echo( $wp_settings_sections['reading']['plsr_speculation_rules']['callback'] );
+		$this->assertStringContainsString( 'This section allows you to control how URLs that your users navigate to are speculatively loaded to improve performance.', $output );
+	}
+
+	/**
+	 * Data provider for testing plsr_render_settings_field.
+	 *
+	 * @return array<string, array<mixed>> Data for testing settings fields.
+	 */
+	public function data_provider_to_test_render_settings_field(): array {
+		return array(
+			'mode'      => array(
+				array(
+					'field'       => 'mode',
+					'title'       => 'Speculation Mode',
+					'description' => 'Prerendering will lead to faster load times than prefetching.',
+				),
+				array(
+					'mode'      => 'prefetch',
+					'eagerness' => 'moderate',
+				),
+				'name="plsr_speculation_rules[mode]"',
+				'value="prefetch"',
+				'Prerendering will lead to faster load times than prefetching.',
+			),
+			'eagerness' => array(
+				array(
+					'field'       => 'eagerness',
+					'title'       => 'Eagerness',
+					'description' => 'The eagerness setting defines the heuristics based on which the loading is triggered.',
+				),
+				array(
+					'mode'      => 'prefetch',
+					'eagerness' => 'moderate',
+				),
+				'name="plsr_speculation_rules[eagerness]"',
+				'value="moderate"',
+				'The eagerness setting defines the heuristics based on which the loading is triggered.',
+			),
+		);
+	}
+
+	/**
+	 * Test rendering of settings fields using data provider.
+	 *
+	 * @dataProvider data_provider_to_test_render_settings_field
+	 * @param array<mixed> $args Arguments for the settings field.
+	 * @param array<mixed> $stored_settings Stored settings values.
+	 * @param string       $name_check HTML name attribute check.
+	 * @param string       $value_check HTML value attribute check.
+	 * @param string       $description_check Description check.
+	 */
+	public function test_plsr_render_settings_field( array $args, array $stored_settings, string $name_check, string $value_check, string $description_check ): void {
+		// Simulate getting stored settings.
+		update_option( 'plsr_speculation_rules', $stored_settings );
+
+		// Capture the output of the settings field rendering.
+		$output = get_echo( 'plsr_render_settings_field', array( $args ) );
+
+		// Check for the presence of form elements.
+		$this->assertStringContainsString( $name_check, $output );
+		$this->assertStringContainsString( $value_check, $output );
+		$this->assertStringContainsString( $description_check, $output );
+	}
 }

plugins/speculation-rules/tests/test-speculation-rules-uninstall.php

@@ -29,8 +29,6 @@ private function require_uninstall(): void {
 
 	/**
 	 * Test option deletion.
-	 *
-	 * @covers ::plsr_delete_plugin_option
 	 */
 	public function test_delete_plugin_option(): void {
 		unregister_setting( 'reading', 'plsr_speculation_rules' );

plugins/speculation-rules/uninstall.php

@@ -8,7 +8,7 @@
 
 // If uninstall.php is not called by WordPress, bail.
 if ( ! defined( 'WP_UNINSTALL_PLUGIN' ) ) {
-	exit;
+	exit;// @codeCoverageIgnore
 }
 
 // For a multisite, delete the option for all sites (however limited to 100 sites to avoid memory limit or timeout problems in large scale networks).