tests: check the posemath parallel tests as a plain program

tests/blendmath compiled blendmath.c into a userspace program with -DULAPI. Since blendmath.c exports pmCircleEffectiveMinRadius() (#4643), EXPORT_SYMBOL is undefined there, which GCC 13 lets through as an implicit int and GCC 14 rejects. The two functions it checks are posemath's now, and posemath uses neither RTAPI nor ULAPI, so it becomes tests/posemath-parallel: a program linked with libposemath, with no blendmath.c to compile and nothing exported from a module for the test. The checks themselves are unchanged.

Author: grandixximo

tests/blendmath/checkresult

@@ -0,0 +1,2 @@
+#!/bin/sh
+grep -q "all parallel checks passed" "$1" && ! grep -q "FAIL" "$1"

tests/blendmath/skip

@@ -0,0 +1,4 @@
+#!/bin/sh
+# Builds a program against the run-in-place headers and library.  Skip
+# when testing installed packages.
+[ -z "$SYSTEM_BUILD" ]

tests/blendmath/test.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -e
+
+# posemath uses neither RTAPI nor ULAPI, so a plain program linked with
+# libposemath checks it; the realtime build's extra maths flags only
+# change calls to sin and cos, which these two functions do not make
+gcc -O2 -Wall -I"$HEADERS" -o test_parallel test_parallel.c \
+    -L"$LIBDIR" -Wl,-rpath,"$LIBDIR" -lposemath -lm
+
+./test_parallel
+rm -f test_parallel

tests/blendmath/test_blendmath.c

@@ -0,0 +1,80 @@
+/*
+ * Checks of the posemath parallel and anti-parallel vector tests.
+ *
+ * Salvaged from the retired meson-only unit_tests/tp/test_blendmath.c
+ * (originally by Robert W. Ellenberg). A plain program linked with
+ * libposemath, which needs neither RTAPI nor ULAPI.
+ */
+
+#include <math.h>
+#include <stdio.h>
+#include <posemath.h>
+
+/* the tolerance the planner's blends use, ANGLE_EPSILON */
+#define ANGLE_EPSILON 1e-6
+#define ANGLE_EPSILON_SQ (ANGLE_EPSILON * ANGLE_EPSILON)
+
+static int failures = 0;
+
+#define CHECK(cond) do { \
+    if (!(cond)) { \
+        printf("FAIL %s:%d: %s\n", __FILE__, __LINE__, #cond); \
+        failures++; \
+    } \
+} while (0)
+
+#define CHECK_FALSE(cond) CHECK(!(cond))
+
+static void test_pmCartCartParallel_numerical(void)
+{
+    PmCartesian u0 = {1, 0, 0};
+    PmCartesian u_close = {cos(ANGLE_EPSILON), sin(ANGLE_EPSILON), 0};
+    int k;
+
+    CHECK(pmCartCartParallel(&u0, &u0, ANGLE_EPSILON_SQ));
+    CHECK_FALSE(pmCartCartParallel(&u0, &u_close, 0.0));
+
+    /* Test that the tolerance makes sense */
+    CHECK_FALSE(pmCartCartParallel(&u0, &u_close, 0.5 * ANGLE_EPSILON_SQ));
+    CHECK(pmCartCartParallel(&u0, &u_close, 1.5 * ANGLE_EPSILON_SQ));
+
+    /* Try a bunch of other angles including anti-parallel */
+    for (k = 1; k <= 7; ++k) {
+        PmCartesian u_far = {cos(PM_PI_4 * k), sin(PM_PI_4 * k), 0};
+        CHECK_FALSE(pmCartCartParallel(&u0, &u_far, ANGLE_EPSILON_SQ));
+    }
+}
+
+static void test_pmCartCartAntiParallel_numerical(void)
+{
+    PmCartesian u0 = {1, 0, 0};
+    PmCartesian u_close = {-cos(ANGLE_EPSILON), sin(ANGLE_EPSILON), 0};
+    PmCartesian u_opposite = {-1, 0, 0};
+    int k;
+
+    CHECK(pmCartCartAntiParallel(&u0, &u_opposite, ANGLE_EPSILON_SQ));
+    CHECK_FALSE(pmCartCartAntiParallel(&u0, &u_close, 0.0));
+
+    /* Test that the tolerance makes sense */
+    CHECK_FALSE(pmCartCartAntiParallel(&u0, &u_close, 0.5 * ANGLE_EPSILON_SQ));
+    CHECK(pmCartCartAntiParallel(&u0, &u_close, 1.5 * ANGLE_EPSILON_SQ));
+
+    /* Try a bunch of other angles including anti-parallel */
+    for (k = 1; k <= 7; ++k) {
+        PmCartesian u_far = {-cos(PM_PI_4 * k), sin(PM_PI_4 * k), 0};
+        CHECK_FALSE(pmCartCartAntiParallel(&u0, &u_far, ANGLE_EPSILON_SQ));
+    }
+}
+
+int main(void)
+{
+    test_pmCartCartParallel_numerical();
+    test_pmCartCartAntiParallel_numerical();
+
+    if (failures) {
+        printf("%d check(s) FAILED\n", failures);
+        return 1;
+    }
+    printf("all parallel checks passed\n");
+    return 0;
+}