Adding test code for String::trim

Author: aentinger

test/CMakeLists.txt

@@ -47,6 +47,7 @@ set(TEST_SRCS
   src/String/test_String.cpp
   src/String/test_toLowerCase.cpp
   src/String/test_toUpperCase.cpp
+  src/String/test_trim.cpp
   src/WCharacter/test_isControl.cpp
   src/WCharacter/test_isDigit.cpp
   src/WCharacter/test_isHexadecimalDigit.cpp

test/src/String/test_trim.cpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2020 Arduino.  All rights reserved.
+ */
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include <catch.hpp>
+
+#include <String.h>
+
+/**************************************************************************************
+ * TEST CODE
+ **************************************************************************************/
+
+TEST_CASE ("Testing String::trim with space at the beginning", "[String-trim-01]")
+{
+  arduino::String str("  hello");
+  str.trim();
+  REQUIRE(strcmp(str.c_str(), "hello") == 0);
+}
+
+TEST_CASE ("Testing String::trim with space at the end", "[String-trim-02]")
+{
+  arduino::String str("hello  ");
+  str.trim();
+  REQUIRE(strcmp(str.c_str(), "hello") == 0);
+}
+
+TEST_CASE ("Testing String::trim with space at both beginng and end", "[String-trim-03]")
+{
+  arduino::String str("  hello  ");
+  str.trim();
+  REQUIRE(strcmp(str.c_str(), "hello") == 0);
+}
+
+TEST_CASE ("Testing String::trim with space in the middle", "[String-trim-04]")
+{
+  arduino::String str("Hello Arduino!");
+  str.trim();
+  REQUIRE(strcmp(str.c_str(), "Hello Arduino!") == 0);
+}