Add test case for & String::operator = (StringSumHelper &&rval)

Author: giulcioffi

test/src/String/test_operators.cpp

@@ -99,4 +99,17 @@ TEST_CASE ("Testing String::operator + (const __FlashStringHelper *)", "[String-
   arduino::String str1("Hello ");
   arduino::String str("Hello Arduino");
   REQUIRE(str.compareTo(str1+F("Arduino")) == 0);
+}
+
+TEST_CASE ("Testing & String::operator = (StringSumHelper &&rval)", "[String-operator+-12]")
+{
+  arduino::String str1("Hello ");
+  arduino::String str = (str1+"Arduino");
+  REQUIRE(str.compareTo("Hello Arduino") == 0);
+  /*
+  arduino::String str1;
+  char ch='!';
+  arduino::String str = (str1+ch);
+  REQUIRE(str.compareTo("Hello!") == 0);
+  */
 }