Added Snapshot-Based Testing to NumberInput Widget

#397 in iced-rs/iced_aw — merged 2026-01-01

Summary of Changes

Enhanced the number_input_displays_correct_initial_value test to include visual regression testing using iced_test simulator's snapshot capabilities.

Changes Made

Modified:

• tests/number_input_integration_tests.rs - Added snapshot validation to existing test (lines 75-88) number_input_displays_correct_initial_value

Output:

• tests/snapshots/number_input_initial_value_100-wgpu.png - Visual baseline (18KB)
• tests/snapshots/number_input_initial_value_100-wgpu.sha256 - Hash baseline (64 bytes)

What This Enables

The test now performs three levels of validation:

1. Text validation - Verifies "100" is displayed (existing)
2. Hash validation - Fast SHA-256 comparison for regression detection (new)
3. Image validation - Pixel-perfect visual comparison against baseline PNG (new)

Testing Approach

Using iced_test::Simulator snapshot API:

  let snapshot = ui.snapshot(&iced::Theme::Light)?;
  assert!(snapshot.matches_hash("tests/snapshots/number_input_initial_value_100")?);
  assert!(snapshot.matches_image("tests/snapshots/number_input_initial_value_100")?);

(On first run, baseline files are auto-generated. Subsequent runs compare against these baselines.)

How to Test

cargo test number_input_displays_correct_initial_value --test number_input_integration_tests

(Test should pass, validating against committed baselines.)

Questions for Review

1. Should we adopt this pattern for other widget tests?
2. The baseline files are committed to enable CI regression detection - is this acceptable for repo size?
3. Should we document this pattern in tests/README.md?

References

• Snapshot API: https://github.com/iced-rs/iced/blob/master/test/src/simulator.rs