Utils/StringUtil: Fixes ltrim and adds a unittest

ltrim had the issue that it would always consume the left-most character
even if it wasn't whitespace. So `FEXLoader` would turn in to
`EXLoader`, even without any whitespace in the string.

Adds a test to ensure this doesn't occur again.

Source/Common/StringUtil.cpp

@@ -3,7 +3,7 @@
 
 namespace FEX::StringUtil {
 void ltrim(fextl::string& s) {
-  s.erase(std::find_if(s.begin(), s.end(), [](int ch) { return !std::isspace(ch); }));
+  s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](int ch) { return !std::isspace(ch); }));
 }
 
 void rtrim(fextl::string& s) {

unittests/APITests/CMakeLists.txt

@@ -3,9 +3,10 @@ set (TESTS
   ArgumentParser
   InterruptableConditionVariable
   Filesystem
+  StringUtils
   )
 
-list(APPEND LIBS FEXCore JemallocLibs)
+list(APPEND LIBS Common FEXCore JemallocLibs)
 
 foreach(API_TEST ${TESTS})
   add_executable(${API_TEST} ${API_TEST}.cpp)

unittests/APITests/StringUtils.cpp

@@ -0,0 +1,95 @@
+#include <catch2/catch_test_macros.hpp>
+#include <Common/StringUtil.h>
+
+static fextl::string ltrim_string(fextl::string in) {
+  FEX::StringUtil::ltrim(in);
+  return in;
+}
+
+static fextl::string rtrim_string(fextl::string in) {
+  FEX::StringUtil::rtrim(in);
+  return in;
+}
+
+static fextl::string trim_string(fextl::string in) {
+  FEX::StringUtil::trim(in);
+  return in;
+}
+
+TEST_CASE("ltrim") {
+  CHECK(ltrim_string("") == "");
+  CHECK(ltrim_string("FEXLoader") == "FEXLoader");
+
+  CHECK(ltrim_string("FEXLoader\n") == "FEXLoader\n");
+  CHECK(ltrim_string("FEXLoader\r") == "FEXLoader\r");
+  CHECK(ltrim_string("FEXLoader\f") == "FEXLoader\f");
+  CHECK(ltrim_string("FEXLoader\t") == "FEXLoader\t");
+  CHECK(ltrim_string("FEXLoader\v") == "FEXLoader\v");
+  CHECK(ltrim_string("FEXLoader ") == "FEXLoader ");
+
+  CHECK(ltrim_string("\nFEXLoader") == "FEXLoader");
+  CHECK(ltrim_string("\rFEXLoader") == "FEXLoader");
+  CHECK(ltrim_string("\fFEXLoader") == "FEXLoader");
+  CHECK(ltrim_string("\tFEXLoader") == "FEXLoader");
+  CHECK(ltrim_string("\vFEXLoader") == "FEXLoader");
+  CHECK(ltrim_string(" FEXLoader") == "FEXLoader");
+
+  CHECK(ltrim_string("\nFEXLoader\n") == "FEXLoader\n");
+  CHECK(ltrim_string("\rFEXLoader\r") == "FEXLoader\r");
+  CHECK(ltrim_string("\fFEXLoader\f") == "FEXLoader\f");
+  CHECK(ltrim_string("\tFEXLoader\t") == "FEXLoader\t");
+  CHECK(ltrim_string("\vFEXLoader\v") == "FEXLoader\v");
+  CHECK(ltrim_string(" FEXLoader ") == "FEXLoader ");
+}
+
+TEST_CASE("rtrim") {
+  CHECK(rtrim_string("") == "");
+  CHECK(rtrim_string("FEXLoader") == "FEXLoader");
+
+  CHECK(rtrim_string("FEXLoader\n") == "FEXLoader");
+  CHECK(rtrim_string("FEXLoader\r") == "FEXLoader");
+  CHECK(rtrim_string("FEXLoader\f") == "FEXLoader");
+  CHECK(rtrim_string("FEXLoader\t") == "FEXLoader");
+  CHECK(rtrim_string("FEXLoader\v") == "FEXLoader");
+  CHECK(rtrim_string("FEXLoader ") == "FEXLoader");
+
+  CHECK(rtrim_string("\nFEXLoader") == "\nFEXLoader");
+  CHECK(rtrim_string("\rFEXLoader") == "\rFEXLoader");
+  CHECK(rtrim_string("\fFEXLoader") == "\fFEXLoader");
+  CHECK(rtrim_string("\tFEXLoader") == "\tFEXLoader");
+  CHECK(rtrim_string("\vFEXLoader") == "\vFEXLoader");
+  CHECK(rtrim_string(" FEXLoader") == " FEXLoader");
+
+  CHECK(rtrim_string("\nFEXLoader\n") == "\nFEXLoader");
+  CHECK(rtrim_string("\rFEXLoader\r") == "\rFEXLoader");
+  CHECK(rtrim_string("\fFEXLoader\f") == "\fFEXLoader");
+  CHECK(rtrim_string("\tFEXLoader\t") == "\tFEXLoader");
+  CHECK(rtrim_string("\vFEXLoader\v") == "\vFEXLoader");
+  CHECK(rtrim_string(" FEXLoader ") == " FEXLoader");
+}
+
+TEST_CASE("trim") {
+  CHECK(trim_string("") == "");
+  CHECK(trim_string("FEXLoader") == "FEXLoader");
+
+  CHECK(trim_string("FEXLoader\n") == "FEXLoader");
+  CHECK(trim_string("FEXLoader\r") == "FEXLoader");
+  CHECK(trim_string("FEXLoader\f") == "FEXLoader");
+  CHECK(trim_string("FEXLoader\t") == "FEXLoader");
+  CHECK(trim_string("FEXLoader\v") == "FEXLoader");
+  CHECK(trim_string("FEXLoader ") == "FEXLoader");
+
+  CHECK(trim_string("\nFEXLoader") == "FEXLoader");
+  CHECK(trim_string("\rFEXLoader") == "FEXLoader");
+  CHECK(trim_string("\fFEXLoader") == "FEXLoader");
+  CHECK(trim_string("\tFEXLoader") == "FEXLoader");
+  CHECK(trim_string("\vFEXLoader") == "FEXLoader");
+  CHECK(trim_string(" FEXLoader") == "FEXLoader");
+
+  CHECK(trim_string("\nFEXLoader\n") == "FEXLoader");
+  CHECK(trim_string("\rFEXLoader\r") == "FEXLoader");
+  CHECK(trim_string("\fFEXLoader\f") == "FEXLoader");
+  CHECK(trim_string("\tFEXLoader\t") == "FEXLoader");
+  CHECK(trim_string("\vFEXLoader\v") == "FEXLoader");
+  CHECK(trim_string(" FEXLoader ") == "FEXLoader");
+}