[migration/ilib-js-to-dart] test: rework test runner and add integration test support

[gouniLee]

Checklist

The following lists affects Pub Points on pub.dev when the package is published.

• Passed the all tests.
• Verified that the example app works.
• Executed the dart format command.
• Added the API description is added if necessary.

Summary

Rework the test runner script to support both unit and integration test modes, add an API-level integration test, and update the CI workflow accordingly. This change is based on work originally done on the develop branch, brought over and updated to align with the current migration branch.

Changes

Script rename & rewrite: execute_unit_test.sh → execute_test.sh

• Renamed to reflect that the script now covers both unit and integration tests
• Add unit | integration | all mode selection (default: all)
• Add --help / -h option with usage documentation
• Per-suite pass/fail reporting
• xvfb-run support for headless widget test execution when DISPLAY is unset
• Updated all references in CI, docs, and benchmark files

New: test/integration/example_app_api_test.dart

• API-level integration test ported from the flutter_js (v1.x) interop to the pure-Dart ILibLoader
• Verifies iLib version (class="token-number">2.0.class="token-number">0) and CLDR version (class="token-number">48.2)
• Validates ILibDateFmt full datetime formatting for en-US locale

CI: .github/workflows/tests.yml

• Switch runner from ubuntu-class="token-number">22.04 to ubuntu-latest
• Install Linux desktop dependencies (clang, cmake, libgtk-class="token-number">3-dev, liblzma-dev, ninja-build, pkg-config, xvfb)

Test Structure

test/ (excluding test/integration/) → Unit tests (datefmt, numfmt, durfmt, etc.)
test/integration/ → API-level integration tests
example/integration_test/ → Widget-based integration tests (requires Linux device)

How to Test

./execute_test.sh              # Run all tests (default)
./execute_test.sh unit         # Unit tests only
./execute_test.sh integration  # Integration tests only
./execute_test.sh --help       # Show usage

[seonmiJin]

The following 34 test files are missing the standard debugPrint('Testing [<filename>] file.'); log line at the start of main().

• test/internal/plural_test.dart
• test/date/datefmt_datetime_calendar_extra_test.dart
• test/root/locale_extra_test.dart
• test/calendar/ (31 files)

[gouniLee]

The following 34 test files are missing the standard debugPrint('Testing [<filename>] file.'); log line at the start of main().

• test/internal/plural_test.dart
• test/date/datefmt_datetime_calendar_extra_test.dart
• test/root/locale_extra_test.dart
• test/calendar/ (31 files)

I updated the test files where debugPrint is missing, and replace the overall imports of material.dart with foundation.dart. This version imports only the required utilities instead of the entire Material widget library.