Improve Test Coverage for Auto Sizes Plugin

plugins/auto-sizes/auto-sizes.php

@@ -19,7 +19,6 @@
 if ( ! defined( 'ABSPATH' ) ) {
 	exit; // Exit if accessed directly.
 }
-// @codeCoverageIgnoreEnd
 
 // Define the constant.
 if ( defined( 'IMAGE_AUTO_SIZES_VERSION' ) ) {
@@ -31,3 +30,4 @@
 require_once __DIR__ . '/includes/auto-sizes.php';
 require_once __DIR__ . '/includes/improve-calculate-sizes.php';
 require_once __DIR__ . '/hooks.php';
+// @codeCoverageIgnoreEnd

plugins/auto-sizes/hooks.php

@@ -10,7 +10,6 @@
 if ( ! defined( 'ABSPATH' ) ) {
 	exit; // Exit if accessed directly.
 }
-// @codeCoverageIgnoreEnd
 
 /**
  * Displays the HTML generator tag for the plugin.
@@ -43,3 +42,4 @@ function auto_sizes_render_generator(): void {
 add_filter( 'render_block_core/post-featured-image', 'auto_sizes_filter_image_tag', 10, 3 );
 add_filter( 'get_block_type_uses_context', 'auto_sizes_filter_uses_context', 10, 2 );
 add_filter( 'render_block_context', 'auto_sizes_filter_render_block_context', 10, 3 );
+// @codeCoverageIgnoreEnd

plugins/auto-sizes/includes/improve-calculate-sizes.php

@@ -76,7 +76,7 @@ function auto_sizes_prime_attachment_caches( $content ): string {
  */
 function auto_sizes_filter_image_tag( $content, array $parsed_block, WP_Block $block ): string {
 	if ( ! is_string( $content ) ) {
-		return '';
+		return ''; // @codeCoverageIgnore
 	}
 
 	$processor = new WP_HTML_Tag_Processor( $content );

plugins/auto-sizes/tests/test-auto-sizes.php

@@ -266,6 +266,15 @@ public function data_provider_to_test_auto_sizes_update_content_img_tag(): array
 				'input'    => '<img src="https://example.com/foo-300x225.jpg" srcset="https://example.com/foo-300x225.jpg 300w, https://example.com/foo-1024x768.jpg 1024w, https://example.com/foo-768x576.jpg 768w, https://example.com/foo-1536x1152.jpg 1536w, https://example.com/foo-2048x1536.jpg 2048w" sizes=",,,,,,,,,auto, (max-width: 650px) 100vw, 650px" loading="lazy">',
 				'expected' => '<img src="https://example.com/foo-300x225.jpg" srcset="https://example.com/foo-300x225.jpg 300w, https://example.com/foo-1024x768.jpg 1024w, https://example.com/foo-768x576.jpg 768w, https://example.com/foo-1536x1152.jpg 1536w, https://example.com/foo-2048x1536.jpg 2048w" sizes="auto, ,,,,,,,,,auto, (max-width: 650px) 100vw, 650px" loading="lazy">',
 			),
+			'expected_when_no_img_tag'                     => array(
+				'input'    => '<p>No image here</p>',
+				'expected' => '<p>No image here</p>',
+			),
+			'expected_when_not_responsive'                 => array(
+				'input'    => '<img src="https://example.com/foo.jpg" loading="lazy">',
+				'expected' => '<img src="https://example.com/foo.jpg" loading="lazy">',
+			),
+
 		);
 	}
 
@@ -279,4 +288,101 @@ public function test_auto_sizes_update_content_img_tag( string $input, string $e
 			auto_sizes_update_content_img_tag( $input )
 		);
 	}
+
+	/**
+	 * @covers ::auto_sizes_attribute_includes_valid_auto
+	 */
+	public function test_auto_sizes_attribute_includes_valid_auto(): void {
+		// Test when 'auto' is the first item in the list.
+		$this->assertTrue( auto_sizes_attribute_includes_valid_auto( 'auto, 100vw' ) );
+
+		// Test when 'auto' is not the first item in the list.
+		$this->assertFalse( auto_sizes_attribute_includes_valid_auto( '100vw, auto' ) );
+	}
+
+	/**
+	 * Provides data for the auto_sizes_update_image_attributes test.
+	 *
+	 * @return array<int,mixed[]> The data for the test cases.
+	 */
+	public function data_provider_for_auto_sizes_update_image_attributes(): array {
+		return array(
+			array(
+				array(
+					'loading' => 'eager',
+					'sizes'   => '100vw',
+				),
+				array(
+					'loading' => 'eager',
+					'sizes'   => '100vw',
+				),
+			),
+
+			// Test when the image is not responsive.
+			array( array( 'loading' => 'lazy' ), array( 'loading' => 'lazy' ) ),
+
+			// Test when 'auto' already exists in the sizes attribute.
+			array(
+				array(
+					'loading' => 'lazy',
+					'sizes'   => 'auto, 100vw',
+				),
+				array(
+					'loading' => 'lazy',
+					'sizes'   => 'auto, 100vw',
+				),
+			),
+
+			// Test when 'auto' needs to be added to the sizes attribute.
+			array(
+				array(
+					'loading' => 'lazy',
+					'sizes'   => '100vw',
+				),
+				array(
+					'loading' => 'lazy',
+					'sizes'   => 'auto, 100vw',
+				),
+			),
+		);
+	}
+
+	/**
+	 * @covers ::auto_sizes_update_image_attributes
+	 *
+	 * @dataProvider data_provider_for_auto_sizes_update_image_attributes
+	 *
+	 * @param array<string, mixed> $attr Attributes to be updated.
+	 * @param array<string, mixed> $expected Expected updated attributes.
+	 */
+	public function test_auto_sizes_update_image_attributes( array $attr, array $expected ): void {
+		$this->assertSame( $expected, auto_sizes_update_image_attributes( $attr ) );
+	}
+
+	/**
+	 * @covers ::auto_sizes_update_content_img_tag
+	 */
+	public function test_auto_sizes_update_content_img_tag_non_string_input(): void {
+		/*
+		 * These tests are separate from the data provider approach because the function
+		 * auto_sizes_update_content_img_tag() expects a string as an argument. Passing a non-string
+		 * value would cause a TypeError. These tests ensure that the function behaves as expected
+		 * when it receives non-string inputs.
+		 */
+		$this->assertSame( '', auto_sizes_update_content_img_tag( array() ) );
+	}
+
+	/**
+	 * @covers ::auto_sizes_update_image_attributes
+	 */
+	public function test_auto_sizes_update_image_attributes_with_null_input(): void {
+		/*
+		 * This test is separate because the main test method uses a data provider
+		 * that expects the $attr parameter to be an array. Passing null directly
+		 * would cause a TypeError due to the type hint. By testing null separately,
+		 * we ensure that the function can handle null inputs gracefully without
+		 * modifying the type hint in the main test method.
+		 */
+		$this->assertSame( array(), auto_sizes_update_image_attributes( null ) );
+	}
 }