test: fix comparison of integers wider than i128

[dhruv-15-03]

Fixes #12874

test rejects integers that don't fit in i128:

$ test 1 -eq 16267277278126277227728782172782882627278282882172762677623672762783782
test: invalid integer '16267277278126277227728782172782882627278282882172762677623672762783782'
$ echo $?
2

GNU has no width limit here. All six integer operators are affected.

integers() parsed both operands as i128, so anything wider failed parse().
They're now parsed into a sign plus decimal digits (leading zeros stripped, -0
normalized) and compared on sign, then digit count, then bytewise. No width limit
and no new dependency.

The set of accepted operands is unchanged - 0x10, 1e3, 123.45, 1_0, 5-,
-, +, empty and non-UTF-8 all still fail the same way with exit 2. The digits
are validated here rather than handed to a bignum type because that reject set has
to be preserved either way, and once the validator exists the comparison is short.

test_values_greater_than_i64_allowed was #[ignore]d, but its input fits in
i128 and passes on main today, so the ignore was stale. Re-enabled, with a new
test for i128::MAX + 1 and i128::MIN - 1.

Checked with cargo test -p uu_test and the test_test integration suite, and
diffed against GNU test over 50 cases covering all six operators, large
negatives, sign and leading-zero handling, and the invalid inputs above. Output
matched. The GNU build I had available was 8.32, not 9.x.

[Copilot]

🟢 Ready to approve

The new comparison logic is self-contained, preserves the documented acceptance/rejection behavior, and is supported by comprehensive new unit and integration tests.

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Pull request overview

This PR fixes GNU compatibility in the test utility by removing the effective i128 width limit for integer comparisons, allowing arbitrarily large (decimal) integer operands while preserving the existing “reject set” and error behavior.

Changes:

• Replace i128 parsing in integer comparisons with a sign+digits representation and lexicographic magnitude comparison (no width limit).
• Re-enable and expand integration tests covering operands beyond i128, large negatives, mixed signs, and normalization (-0, +0, leading zeros).
• Add unit tests validating correct ordering and continued rejection of malformed/non-decimal inputs.

File summaries

File	Description
tests/by-util/test_test.rs	Re-enables stale ignored test and adds integration coverage for very large integer comparisons and malformed operand handling.
src/uu/test/src/test.rs	Implements width-unlimited integer comparison by parsing operands into sign+digits and comparing by sign/length/lexicographic order; adds unit tests.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Lite

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[codspeed-hq]

Merging this PR will improve performance by 22.61%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 344 untouched benchmarks
⏩ 46 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	df_with_path	699.9 µs	570.8 µs	+22.61%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing dhruv-15-03:test-bigint-compare (a31150b) with main (b13ee7a)}

Footnotes

1. 46 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/tty-eof (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/retry (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/cut/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)

[RenjiSann]

PR message is much too verbose, please write it by hand instead of proxying the burden of understanding both your patch and AI slop to maintainers.

[dhruv-15-03]

Fair point - I've cut it down to the problem, the cause and the fix.

[RenjiSann]

Thank you !