Add few missing tests

tests/test_SymbolTable.cpp

@@ -13,14 +13,19 @@ TEST_CASE("SymbolTable", "[language]")
 
     using namespace TAO_PEGTL_NAMESPACE;
     position begin_position{internal::iterator{"fixture"}, "fixture"};
+    begin_position.byte = 2;
 
     auto [i_symbol_a, created_a] = root_st->add("a", begin_position);
     REQUIRE(created_a);
 
+    REQUIRE(i_symbol_a->second.position().byte == 2);
+
     // Check that one cannot build another "a" in this table
     REQUIRE(not root_st->add("a", begin_position).second);
 
     position use_position{internal::iterator{"fixture"}, "fixture"};
+    use_position.byte = 3;   // after declarative position
+
     auto [i_search_a, found_a] = root_st->find("a", use_position);
     REQUIRE(found_a);
     REQUIRE(i_search_a == i_symbol_a);
@@ -65,6 +70,9 @@ TEST_CASE("SymbolTable", "[language]")
 
       REQUIRE(std::holds_alternative<double>(attributes_a.value()));
 
+      const auto const_attribute_a = attributes_a;
+      REQUIRE(std::get<double>(const_attribute_a.value()) == 2.3);
+
       {
         std::stringstream value_output;
         value_output << attributes_a;