Add tests for RuntimeError

tests/CMakeLists.txt

@@ -70,6 +70,7 @@ add_executable (unit_tests
   test_PCG.cpp
   test_PugsAssert.cpp
   test_RevisionInfo.cpp
+  test_RuntimeError.cpp
   test_SparseMatrixDescriptor.cpp
   test_SymbolTable.cpp
   test_TinyMatrix.cpp

tests/test_RuntimeError.cpp

+#include <catch2/catch.hpp>
+
+#include <language/utils/RuntimeError.hpp>
+
+// clazy:excludeall=non-pod-global-static
+
+TEST_CASE("RuntimeError", "[language]")
+{
+  RuntimeError e{"error message"};
+  REQUIRE(e.message() == "error message");
+}