Add a test for complex norm and abs

ChangeLog:

	* tests/complex-math.cpp: New file.

Author: mattkretz

tests/complex-math.cpp

@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/* Copyright © 2024–2026 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH
+ *                       Matthias Kretz <m.kretz@gsi.de>
+ */
+// requires complex
+
+#include "unittest.h"
+
+static constexpr bool is_iec559 =
+#ifdef __GCC_IEC_559
+      __GCC_IEC_559 >= 2;
+#elif defined __STDC_IEC_559__
+      __STDC_IEC_559__ == 1;
+#else
+      false;
+#endif
+
+// no tests for non-complex types
+template <typename V>
+  struct Tests {};
+
+template <typename V>
+  requires complex_like<typename V::value_type>
+  struct Tests<V>
+  {
+    using T = typename V::value_type;
+    using M = typename V::mask_type;
+    using L = std::numeric_limits<T>;
+    using RV = simd::rebind_t<typename T::value_type, V>;
+
+    ADD_TEST(Norm) {
+      std::tuple {test_iota<V>},
+      [](auto& t, const V x) {
+	const V y = {x.real(), x.real() / 3};
+	t.verify_equal(norm(x), RV([&](int i) { return std::norm(x[i]); }));
+	t.verify_equal(norm(y), RV([&](int i) { return std::norm(y[i]); }));
+      }
+    };
+
+    ADD_TEST(Abs) {
+      std::tuple {test_iota<V>},
+      [](auto& t, const V x) {
+	if !consteval
+	  {
+	    const V y = {x.real(), x.real() / 3};
+	    t.verify_equal(abs(x), RV([&](int i) { return std::abs(x[i]); }));
+	    t.verify_equal(abs(y), RV([&](int i) { return std::abs(y[i]); }));
+	  }
+      }
+    };
+  };