inclusive_scan smoke test

test/stdpar/tests/inclusive_scan.cpp

@@ -0,0 +1,55 @@
+#include <cstddef>
+#include <execution>
+#include <numeric>
+#include <vector>
+
+int main()
+{
+  constexpr std::size_t N = 1 << 16;
+
+  std::vector<int> in(N);
+  std::vector<int> out(N);
+
+  std::iota(in.start(), in.end(), 1);
+
+  // inclusive_scan with default initial value
+  std::inclusive_scan(std::execution::par, in.begin(), in.end(), out.begin());
+
+  for (std::size_t i = 0; i < N; ++i)
+  {
+    const int expected = static_cast<int>(i + 1);
+    if (out[i] != expected)
+    {
+      return 1;
+    }
+  }
+
+  // inclusive_scan with non-zero initial value
+  const int init = 42;
+  std::inclusive_scan(std::execution::par, in.begin(), in.end(), out.begin(), init);
+
+  for (std::size_t i = 0; i < N; ++i)
+  {
+    const int expected = init + static_cast<int>(i + 1);
+    if (out[i] != expected)
+    {
+      return 1;
+    }
+  }
+
+  //   inclusive_scan with only binary ops and no init value
+  std::inclusive_scan(std::execution::par, in.begin(), in.end(), out.begin(), [](int lhs, int rhs) {
+    return lhs + rhs + 1;
+  });
+
+  for (std::size_t i = 0; i < N; ++i)
+  {
+    const int expected = static_cast<int>(2 * i + 1);
+    if (out[i] != expected)
+    {
+      return 1;
+    }
+  }
+
+  return 0;
+}