[mgradwohl]

Description

src/UI/ChartWidgets.h still carried four value-buffer helpers that nothing under src/, benchmarks/ or the fuzz targets calls. Only tests used them. This moves them, and the writeReducedPoint helper that only the first two used, into a test-support header. Their code is unchanged.

What moved where

• reduceSeriesKeepingGaps, reduceSeriesMinMax, reduceAlignedSeries, holdLastValuesToNow and writeReducedPoint now live in tests/UI/ChartReferenceHelpers.h, namespace UI::Widgets::TestReference. The header's file comment says what they are and that nothing under src/ may include it.
• Production keeps the shared primitives: forEachStrideReducedPoint, forEachMinMaxReducedPoint, forEachAlignedReducedPoint, reduceSeriesMinMaxPoints, reduceAlignedPoints, holdLastValueToNow, holdTimeToNow, appendHeldValues and the gather functions.

Tests

• tests/UI/test_ChartWidgets.cpp includes the new header and pulls in the four helpers with using TestReference::.... Every existing test is still there and its assertions are unchanged. That includes perf(ui): chart sections keep their per-publication series and window maxima between samples, so a frame between samples rebuilds only x (#843) #2937's equivalence test (HeldValuesAndAHeldTimeDrawWhatHoldLastValuesToNowDoes), which still checks appendHeldValues + holdTimeToNow against holdLastValuesToNow, along with the stale, empty, mismatched-length and NaN hold cases and the peak, gap, end-point, budget and aligned-series tests.
• tests/App/test_ProcessDetailsHistory.cpp: two tests held a series to now with holdLastValuesToNow. They now use the charts' own appendHeldValues + holdTimeToNow, with the same assertions. This is the path Process Details actually draws with, so the App test doesn't need a UI test header.
• tests/UI/test_ChartWidgetsEdgeCases.cpp already used only reduceSeriesMinMaxPoints, so it is unchanged.

Docs and comments

• The descriptions that were on the removed wrappers now sit on the production primitives:
  • the stride-and-gap rule is on forEachStrideReducedPoint;
  • the aligned bucketing and bucket-collapse rationale ([Refactor] Line weights, fills and decimation caps differ between charts #1022, fix(ui): one style for history series; remove dead chart branches and mouse text #1061) is on forEachAlignedReducedPoint;
  • the "all reach now, or none does" contract is on holdTimeToNow and appendHeldValues.
• Every other comment in ChartWidgets.h, ProcessDetailsCharts.cpp and SystemMetricsPanel.cpp that named a removed helper now names a production one.
• Includes: none of ChartWidgets.h's includes was needed only by the moved helpers (<initializer_list>, <limits>, <algorithm>, <array> and <type_traits> all still have production users), so none was removed.

git grep finds no remaining reference to the moved names outside tests/UI/. Production behaviour does not change: only unused inline templates and functions left the header, plus comment edits.

Fixes #3116

PR Size

Small: about 230 lines added and 185 removed. Most of it is the moved code: about 170 lines out of ChartWidgets.h, about 157 into the new header.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Build/CI improvement

Refactor, no runtime change: test-only code moved out of a production header, plus comment updates.

Checklist

• I have read the CONTRIBUTING guidelines
• My code follows the project's coding standards
• I have run clang-tidy and addressed any warnings (no local build: see Testing)
• I have run clang-format on my changes
• I have run pre-commit run --all-files or installed pre-commit hooks (pre-commit run --files on the touched files: all passed)
• I have added tests that prove my fix/feature works (existing tests kept and moved to the reference header; no new behaviour to test)
• All new and existing tests pass (CI is the first build)
• I have updated documentation as needed

Testing

Not built locally. Free RAM stayed near 5.5 GB, under this machine's 8 GB build threshold, for the whole 15-minute wait, so CI is the first build and test run of this change. The suites to watch are ChartWidgetsTest, ChartWidgetsStackTest, ChartWidgetsReduceTest and the other suites in test_ChartWidgets.cpp and test_ChartWidgetsEdgeCases.cpp, plus ProcessDetailsHistoryTest.

git grep -n -E "reduceSeriesKeepingGaps|reduceSeriesMinMax\b|reduceAlignedSeries|holdLastValuesToNow|writeReducedPoint"   # only tests/UI/
clang-format -i <touched files>
pre-commit run --files <touched files>
cmake --workflow --preset win-dev   # left to CI

Additional Notes

• tests/UI/ChartReferenceHelpers.h is reached as "UI/ChartReferenceHelpers.h" through the tests directory that is already on TaskSmackTests' include path, the same way "Core/WindowSizeTestUtils.h" is. It is header-only, so tests/CMakeLists.txt doesn't change.
• Labels: agent:Windows, refactoring, ui, testing. Milestone v0.10.0, so no backport label.

🤖 Generated with Claude Code

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None