Fix String::Trim and add test

src/openrct2/core/String.cpp

@@ -399,36 +399,29 @@ namespace String
         codepoint_t codepoint;
         const utf8 * ch = s.c_str();
         const utf8 * nextCh;
-        const utf8 * firstNonWhitespace = nullptr;
+        const utf8 * startSubstr = nullptr;
-        const utf8 * lastNonWhitespace = nullptr;
+        const utf8 * endSubstr = nullptr;
         while ((codepoint = GetNextCodepoint(ch, &nextCh)) != '\0')
         {
             bool isWhiteSpace = codepoint <= WCHAR_MAX && iswspace((wchar_t)codepoint);
             if (!isWhiteSpace)
             {
-                if (firstNonWhitespace == nullptr)
+                if (startSubstr == nullptr)
                 {
-                    firstNonWhitespace = ch;
+                    startSubstr = ch;
                 }
-                lastNonWhitespace = ch;
+                endSubstr = ch;
             }
             ch = nextCh;
         }
 
-        if (firstNonWhitespace != nullptr &&
+        if (startSubstr == nullptr)
-            firstNonWhitespace != s.c_str())
-        {
-            size_t newStringSize = ch - firstNonWhitespace;
-            return std::string(firstNonWhitespace, newStringSize);
-        }
-        else if (lastNonWhitespace != nullptr)
-        {
-            size_t newStringSize = lastNonWhitespace - s.c_str() + 1;
-            return std::string(s.c_str(), newStringSize);
-        }
-        else
         {
+            // String is all whitespace
             return std::string();
         }
+
+        size_t stringLength = endSubstr - startSubstr + 1;
+        return std::string(startSubstr, stringLength);
     }
 }

test/tests/StringTest.cpp

@@ -0,0 +1,27 @@
+#include <string>
+#include <tuple>
+#include <gtest/gtest.h>
+#include <openrct2/core/String.hpp>
+
+using TCase = std::tuple<std::string, std::string>;
+
+class StringTest : public testing::TestWithParam<TCase>
+{
+};
+
+INSTANTIATE_TEST_CASE_P(TrimData, StringTest, testing::Values(
+    TCase("string", "string"),
+    TCase("  string", "string"),
+    TCase("string  ", "string"),
+    TCase("   some   string  ", "some   string"),
+    TCase("      ", ""),
+    TCase("", "")
+));
+TEST_P(StringTest, Trim)
+{
+    auto testCase = GetParam();
+    std::string input = std::get<0>(testCase);
+    std::string expected = std::get<1>(testCase);
+    std::string actual = String::Trim(input);
+    ASSERT_EQ(expected, actual);
+}

test/tests/tests.vcxproj

@@ -45,7 +45,6 @@
       <SubSystem>Console</SubSystem>
     </Link>
   </ItemDefinitionGroup>
-
   <!-- Files -->
   <ItemGroup>
   </ItemGroup>
@@ -56,7 +55,7 @@
     <ClCompile Include="sawyercoding_test.cpp" />
     <ClCompile Include="$(GtestDir)\src\gtest-all.cc" />
     <ClCompile Include="tests.cpp" />
+    <ClCompile Include="StringTest.cpp" />
   </ItemGroup>
-
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
 </Project>