Add private od_print_disabled_reasons() and test coverage

plugins/optimization-detective/optimization.php

@@ -105,20 +105,13 @@ function od_maybe_add_template_output_buffer_filter(): void {
 			add_action(
 				'wp_print_footer_scripts',
 				static function () use ( $reasons ): void {
-					foreach ( $reasons as $reason ) {
-						wp_print_inline_script_tag(
-							sprintf(
-								'console.info( %s );',
-								(string) wp_json_encode( '[Optimization Detective] ' . $reason )
-							),
-							array( 'type' => 'module' )
-						);
-					}
+					od_print_disabled_reasons( $reasons );
 				}
 			);
 		}
 		return;
 	}
+
 	$callback = 'od_optimize_template_output_buffer';
 	if (
 		function_exists( 'perflab_wrap_server_timing' )
@@ -132,6 +125,28 @@ function_exists( 'perflab_server_timing_use_output_buffer' )
 	add_filter( 'od_template_output_buffer', $callback );
 }
 
+/**
+ * Prints the reasons why Optimization Detective is not optimizing the current page.
+ *
+ * This is only used when WP_DEBUG is enabled.
+ *
+ * @since n.e.x.t
+ * @access private
+ *
+ * @param string[] $reasons Reason messages.
+ */
+function od_print_disabled_reasons( array $reasons ): void {
+	foreach ( $reasons as $reason ) {
+		wp_print_inline_script_tag(
+			sprintf(
+				'console.info( %s );',
+				(string) wp_json_encode( '[Optimization Detective] ' . $reason )
+			),
+			array( 'type' => 'module' )
+		);
+	}
+}
+
 /**
  * Determines whether the current response can be optimized.
  *

plugins/optimization-detective/tests/test-optimization.php

@@ -215,6 +215,25 @@ public function test_od_maybe_add_template_output_buffer_filter( Closure $set_up
 		$this->assertSame( $expected_has_filter, has_filter( 'od_template_output_buffer' ) );
 	}
 
+	/**
+	 * Test od_print_disabled_reasons().
+	 *
+	 * @covers ::od_print_disabled_reasons
+	 */
+	public function test_od_print_disabled_reasons(): void {
+		$this->assertSame( '', get_echo( 'od_print_disabled_reasons', array( array() ) ) );
+		$foo_message = get_echo( 'od_print_disabled_reasons', array( array( 'Foo' ) ) );
+		$this->assertStringContainsString( '<script', $foo_message );
+		$this->assertStringContainsString( 'console.info(', $foo_message );
+		$this->assertStringContainsString( '[Optimization Detective] Foo', $foo_message );
+
+		$foo_and_bar_messages = get_echo( 'od_print_disabled_reasons', array( array( 'Foo', 'Bar' ) ) );
+		$this->assertStringContainsString( '<script', $foo_and_bar_messages );
+		$this->assertStringContainsString( 'console.info(', $foo_and_bar_messages );
+		$this->assertStringContainsString( '[Optimization Detective] Foo', $foo_and_bar_messages );
+		$this->assertStringContainsString( '[Optimization Detective] Bar', $foo_and_bar_messages );
+	}
+
 	/**
 	 * Data provider.
 	 *