FEAT: Add meson build + ctypes/pytest test driver with MPFR oracle

Top-level meson build compiles each op's test kernels into their own
dlopen-able plugin, with Highway as a build-time subproject. The
numpy_sr package dlopens the plugins and dispatches over numpy buffers
via ctypes; tests are plain pytest.

- Targets per ISA with ops exposed at module scope (numpy_sr.sin),
  accuracy= keyword taking Precise() profiles, fenv context manager.
- Correctly-rounded MPFR reference kernels as oracle.
- ULP assertion helpers and reusable test-data generators; first suite
  covers sin/cos.
- Random test seed by default (NPSR_SEED overrides), shared across
  xdist workers so all sweep identical data.
- spin build/test commands
- CI smoke + stress.

Author: seiko2plus

.github/workflows/tests.yml

@@ -0,0 +1,42 @@
+# Per-arch `spin build` + `spin test` on native hosted runners: a fast smoke
+# pass first, then the stress sweeps (MPFR-validated, marked `stress`).
+name: Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: ${{ matrix.arch }}
+    runs-on: ${{ matrix.runner }}
+    timeout-minutes: 60
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arch: x86-64
+            runner: ubuntu-24.04
+          - arch: arm64
+            runner: ubuntu-24.04-arm
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'  # project minimum
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y --no-install-recommends libmpfr-dev
+          python -m pip install -r test_requirements.txt
+      - name: Build
+        run: spin build
+      - name: Smoke test
+        run: spin test -- -m "not stress" -q
+      - name: Stress test
+        run: spin test -- -m stress -q

.gitignore

@@ -22,3 +22,16 @@
 ###########
 *.patch
 *.diff
+build/
+build-install/
+# Test unit's default report artifact (override path via NPSR_TEST_REPORT)
+/npsr-test-report.json
+subprojects/highway/
+subprojects/packagecache/
+subprojects/googletest-1.17.0/
+.venv/
+.cache/
+__pycache__/
+# Hypothesis example database (numpy_sr test suite)
+.hypothesis/
+/subprojects/.wraplock

.spin/cmds.py

@@ -1,5 +1,6 @@
 import pathlib
 import sys
+
 import click
 
 curdir = pathlib.Path(__file__).parent

meson.build

@@ -0,0 +1,20 @@
+project(
+  'npsr',
+  'cpp',
+  version: '0.1.0',
+  meson_version: '>= 1.3.0',
+  license: 'BSD-3-Clause',
+  default_options: [
+    'cpp_std=c++17',
+    'buildtype=release',
+  ],
+)
+
+py = import('python').find_installation()
+npsr_inc = include_directories('.')
+
+# `numpy_sr` scans the op sources (npsr/**/tests/<op>.cc), builds them, and
+# installs the Python package (harness + kernels + tests).
+if get_option('tests').disable_auto_if(meson.is_subproject()).allowed()
+  subdir('numpy_sr')
+endif

meson_options.txt

@@ -0,0 +1 @@
+option('tests', type: 'feature', value: 'auto', description: 'Build per-operation shared libraries for the pytest harness')

npsr/lut-inl.h

@@ -6,6 +6,7 @@
 #endif
 
 #include <tuple>
+#include <limits>
 
 #include "npsr/hwy.h"
 

npsr/trig/tests/cos.cc

@@ -0,0 +1,19 @@
+// npsr Cos test library: one Operation registered per Highway target;
+// npsr_py_load comes from pyext.cc, the MPFR oracle from mpfr.cc.
+#undef HWY_TARGET_INCLUDE
+#define HWY_TARGET_INCLUDE "npsr/trig/tests/cos.cc"
+#include "hwy/foreach_target.h"  // IWYU pragma: keep
+#include "hwy/highway.h"
+#include "numpy_sr/pyext-inl.h"
+
+HWY_BEFORE_NAMESPACE();
+namespace npsr::py::HWY_NAMESPACE {
+struct CosFn {
+  template <class P, class V>
+  V operator()(P& p, V v) const {
+    return ::npsr::HWY_NAMESPACE::Cos(p, v);
+  }
+};
+static RegisteredOperation reg_cos{MakeUnaryOperation<CosFn>("cos")};
+}  // namespace npsr::py::HWY_NAMESPACE
+HWY_AFTER_NAMESPACE();

npsr/trig/tests/mpfr.cc

@@ -0,0 +1,8 @@
+// MPFR reference oracles for all trig ops (numpy_sr.mpfr.*): one plugin
+// library, no Highway targets; npsr_py_load comes from pyext.cc.
+#include "numpy_sr/pyext-mpfr.h"
+
+namespace npsr::py {
+static RegisteredOperation ops{MakeMpfr<mpfr_sin>("sin"),
+                               MakeMpfr<mpfr_cos>("cos")};
+}  // namespace npsr::py

npsr/trig/tests/sin.cc

@@ -0,0 +1,19 @@
+// npsr Sin test library: one Operation registered per Highway target;
+// npsr_py_load comes from pyext.cc, the MPFR oracle from mpfr.cc.
+#undef HWY_TARGET_INCLUDE
+#define HWY_TARGET_INCLUDE "npsr/trig/tests/sin.cc"
+#include "hwy/foreach_target.h"  // IWYU pragma: keep
+#include "hwy/highway.h"
+#include "numpy_sr/pyext-inl.h"
+
+HWY_BEFORE_NAMESPACE();
+namespace npsr::py::HWY_NAMESPACE {
+struct SinFn {
+  template <class P, class V>
+  V operator()(P& p, V v) const {
+    return ::npsr::HWY_NAMESPACE::Sin(p, v);
+  }
+};
+static RegisteredOperation reg_sin{MakeUnaryOperation<SinFn>("sin")};
+}  // namespace npsr::py::HWY_NAMESPACE
+HWY_AFTER_NAMESPACE();