[intl4x] Add randomized equivalence test for NumberFormat constructors by mosuem · Pull Request #1118 · dart-lang/i18n

mosuem · 2026-10-30T07:26:55Z

Note

This PR was generated by an AI coding agent (Jetski) on behalf of @mosuem.

Adds test/number_format_equivalence_test.dart. It checks that NumberFormat.percent, NumberFormat.compact and NumberFormat.currency format exactly like the general NumberFormat constructor with the equivalent style or notation, for 300 random option combinations each, and that no combination throws.

The random options cover every parameter of these constructors: locale, sign display, notation, grouping, numbering system, rounding mode, trailing zero display, minimum integer digits, fraction and significant digits (with rounding priority), currency display and sign, and the style for compact. The seed is fixed, so results are reproducible, and a failure lists the first failing combinations.

The test would have caught both bugs fixed earlier in this stack:

Without the NumberFormat.percent fix ([intl4x] Fix NumberFormat.percent ignoring digits #1115), 149 of 300 combinations format differently.
Without the currency fix ([intl4x] Fix currency formatting throwing for a small maximum of fraction digits #1117), 6 of 300 combinations throw maximumFractionDigits value is out of range.

Like the other tests for these constructors, it only runs on web (the group is tagged icu4xUnimplemented), because they are not implemented on native yet.

Verified locally: dart analyze --fatal-infos, dart format --output=none --set-exit-if-changed ., dart test -p node -x ecmaUnsupported, dart test -p node -c dart2wasm on the number format tests, and dart test on the number format tests (VM, where the new tests are skipped) pass. The new tests take well under a second.

gemini-code-assist · 2026-10-30T07:27:03Z

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a randomized testing suite for the intl4x package to verify that specialized NumberFormat convenience constructors behave identically to the general constructor when provided with equivalent configurations. This approach helps ensure consistency across the API and proactively identifies edge cases or errors in formatting logic.

Highlights

New Randomized Equivalence Test: Added a new test file that performs randomized equivalence checks between convenience NumberFormat constructors (percent, compact, currency) and the general NumberFormat constructor.
Robustness and Reproducibility: The test uses a fixed seed for reproducibility and covers 300 random option combinations per constructor to ensure consistency and catch potential regressions.

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github-actions · 2026-10-30T07:28:19Z

PR Health

Breaking changes ✔️

Package	Change	Current Version	New Version	Needed Version	Looking good?
intl4x	None	1.0.1	1.0.2-wip	1.0.2-wip	✔️

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// Copyright (c) 2026, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

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gemini-code-assist

Code Review

This pull request introduces a new test file number_format_equivalence_test.dart to verify that the convenience constructors of NumberFormat (percent, compact, and currency) behave identically to the general NumberFormat constructor when configured with equivalent options. The reviewer suggests exporting NumberingSystem from package:intl4x/number_format.dart in a future change, as it is currently imported from datetime_format.dart but used in NumberFormat constructors.

gemini-code-assist · 2026-10-30T07:28:22Z

+
+import 'dart:math';
+
+import 'package:intl4x/datetime_format.dart' show NumberingSystem;


It looks like NumberingSystem is imported from package:intl4x/datetime_format.dart because it is not currently exported by package:intl4x/number_format.dart. Since NumberFormat accepts NumberingSystem? numberingSystem in its constructors, NumberingSystem should ideally be exported by package:intl4x/number_format.dart to make the API more cohesive and discoverable for users. Consider exporting NumberingSystem in pkgs/intl4x/lib/number_format.dart in a follow-up change.

robertbastian · 2026-10-30T21:48:09Z

+
+import 'dart:math';
+
+import 'package:intl4x/datetime_format.dart' show NumberingSystem;


Checks that NumberFormat.percent, NumberFormat.compact and NumberFormat.currency format exactly like the general NumberFormat constructor with the equivalent style or notation, for random option combinations with a fixed seed, and that no combination throws. It catches both the dropped digits in NumberFormat.percent and the currency fraction digits error fixed earlier in this stack.

mosuem added this pull request to stack #1119 October 30, 2026 07:26

github-actions Bot added the package:intl4x label Oct 30, 2026

This was referenced Oct 30, 2026

[intl4x] Fix NumberFormat.percent ignoring digits #1115

Merged

[intl4x] Fix currency formatting throwing for a small maximum of fraction digits #1117

Open

mosuem marked this pull request as ready for review October 30, 2026 07:28

mosuem requested a review from robertbastian as a code owner October 30, 2026 07:28

mosuem mentioned this pull request Oct 30, 2026

[intl4x] Fix NumberFormat.percent ignoring digits #1114

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gemini-code-assist Bot reviewed Oct 30, 2026

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robertbastian approved these changes Oct 30, 2026

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mosuem force-pushed the intl4x-number-format-equivalence-test branch from 7967728 to 5991ed8 Compare October 31, 2026 01:49

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[intl4x] Add randomized equivalence test for NumberFormat constructors - #1118

[intl4x] Add randomized equivalence test for NumberFormat constructors#1118
mosuem wants to merge 1 commit into
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		import 'dart:math';

		import 'package:intl4x/datetime_format.dart' show NumberingSystem;

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