Add few missing tests

tests/test_ConcatExpressionProcessor.cpp

@@ -71,4 +71,28 @@ TEST_CASE("ConcatExpressionProcessor", "[language]")
   {
     CHECK_CONCAT_EXPRESSION_RESULT(R"(let s:string, s = "foo_"; s = s+true;)", "s", std::string{"foo_1"});
   }
+
+  SECTION("string + R^1")
+  {
+    std::ostringstream os;
+    os << "foo_" << TinyVector<1>{1};
+
+    CHECK_CONCAT_EXPRESSION_RESULT(R"(let x:R^1, x = 1; let s:string, s = "foo_"; s = s+x;)", "s", os.str());
+  }
+
+  SECTION("string + R^2")
+  {
+    std::ostringstream os;
+    os << "foo_" << TinyVector<2>{1, 2};
+
+    CHECK_CONCAT_EXPRESSION_RESULT(R"(let x:R^2, x = (1,2); let s:string, s = "foo_"; s = s+x;)", "s", os.str());
+  }
+
+  SECTION("string + R^3")
+  {
+    std::ostringstream os;
+    os << "foo_" << TinyVector<3>{1, 2, 3};
+
+    CHECK_CONCAT_EXPRESSION_RESULT(R"(let x:R^3, x = (1,2,3); let s:string, s = "foo_"; s = s+x;)", "s", os.str());
+  }
 }