Added testing coverage for the Sidebar and SidebarWithContent widgets

#390 in iced-rs/iced_aw — merged 2025-12-30

Summary

Changes to src/widget/sidebar/sidebar.rs

• Implemented operate() method for Sidebar to expose tab labels and close icons for testing
• Modified operate() method for SidebarWithContent to handle both sidebar positions (Start/End) and properly traverse the widget tree
• Added unit tests

New file: tests/sidebar_integration_tests.rs

• Integration tests using iced_test::Simulator

  cargo test --lib sidebar::sidebar::tests && cargo test --test sidebar_integration_tests