Add tests for NaNHelper

tests/CMakeLists.txt

@@ -85,6 +85,7 @@ add_executable (unit_tests
   test_ListAffectationProcessor.cpp
   test_MathModule.cpp
   test_NameProcessor.cpp
+  test_NaNHelper.cpp
   test_OStreamProcessor.cpp
   test_ParseError.cpp
   test_PETScUtils.cpp

tests/test_NaNHelper.cpp

+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_all.hpp>
+
+#include <utils/NaNHelper.hpp>
+
+#include <sstream>
+
+// clazy:excludeall=non-pod-global-static
+
+TEST_CASE("NaNHelper", "[utils]")
+{
+  SECTION("signaling NaN")
+  {
+    std::ostringstream ost_nan_helper;
+    ost_nan_helper << NaNHelper(std::numeric_limits<double>::signaling_NaN());
+
+    REQUIRE(ost_nan_helper.str() == "nan");
+  }
+
+  SECTION("valid double")
+  {
+    std::ostringstream ost_nan_helper;
+    ost_nan_helper << NaNHelper(double{3.2});
+
+    std::ostringstream ost;
+    ost << double{3.2};
+    REQUIRE(ost_nan_helper.str() == ost.str());
+  }
+
+  SECTION("non arithmetic type")
+  {
+    std::string s = "foo";
+    std::ostringstream ost_nan_helper;
+    ost_nan_helper << NaNHelper(s);
+
+    REQUIRE(ost_nan_helper.str() == s);
+  }
+}