diff --git a/src/yycc/carton/lexer61.cpp b/src/yycc/carton/lexer61.cpp
index dff829a..db19253 100644
--- a/src/yycc/carton/lexer61.cpp
+++ b/src/yycc/carton/lexer61.cpp
@@ -2,11 +2,12 @@
 
 namespace yycc::carton::lexer61 {
 
-    Lexer61::Lexer61() : m_ArgsCollection(), m_CurrentArg(), m_CurrentChar(u8'\0'), m_State(LexerState::Space), m_PrevState(LexerState::Space) {}
+    Lexer61::Lexer61() :
+        m_ArgsCollection(), m_CurrentArg(), m_CurrentChar(u8'\0'), m_State(LexerState::Space), m_PrevState(LexerState::Space) {}
 
     Lexer61::~Lexer61() {}
 
-    LexerResult<std::vector<std::u8string_view>> Lexer61::lex(const std::u8string_view &cmd) {
+    LexerResult<std::vector<std::u8string>> Lexer61::lex(const std::u8string_view &cmd) {
         // Clear variables when we start a new lex.
         this->reset();
 
@@ -67,20 +68,6 @@ namespace yycc::carton::lexer61 {
         }
     }
 
-    LexerResult<std::vector<std::u8string>> Lexer61::owend_lex(const std::u8string_view &cmd) {
-        auto rv = this->lex(cmd);
-        if (rv.has_value()) {
-            auto source = std::move(rv.value());
-            std::vector<std::u8string> elems;
-            for (const auto &strl_view : source) {
-                elems.emplace_back(std::u8string(strl_view));
-            }
-            return elems;
-        } else {
-            std::unexpected(rv.error());
-        }
-    }
-
     void Lexer61::reset() {
         // Because these value may be moved, so we need assign them with new value,
         // rather clear them.
diff --git a/src/yycc/carton/lexer61.hpp b/src/yycc/carton/lexer61.hpp
index f64f43e..139a8df 100644
--- a/src/yycc/carton/lexer61.hpp
+++ b/src/yycc/carton/lexer61.hpp
@@ -24,8 +24,7 @@ namespace yycc::carton::lexer61 {
         YYCC_DEFAULT_COPY_MOVE(Lexer61)
 
     public:
-        LexerResult<std::vector<std::u8string_view>> lex(const std::u8string_view& cmd);
-        LexerResult<std::vector<std::u8string>> owend_lex(const std::u8string_view& cmd);
+        LexerResult<std::vector<std::u8string>> lex(const std::u8string_view& cmd);
 
     private:
         void reset();
@@ -36,11 +35,11 @@ namespace yycc::carton::lexer61 {
         void proc_escape();
         void proc_normal();
 
-        std::vector<std::u8string_view> m_ArgsCollection; ///< Internal result holder.
-        std::u8string m_CurrentArg;                   ///< Holding current building commandline argument.
-        char8_t m_CurrentChar;                    ///< Holding current char analysing.
-        LexerState m_State;                       ///< Recording current state.
-        LexerState m_PrevState;                   ///< Recording previous state.
+        std::vector<std::u8string> m_ArgsCollection; ///< Internal result holder.
+        std::u8string m_CurrentArg;                  ///< Holding current building commandline argument.
+        char8_t m_CurrentChar;                       ///< Holding current char analysing.
+        LexerState m_State;                          ///< Recording current state.
+        LexerState m_PrevState;                      ///< Recording previous state.
     };
 
 } // namespace yycc::carton::lexer61
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 3c72060..31e788a 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -42,6 +42,7 @@ PRIVATE
     yycc/carton/tabulate.cpp
     yycc/carton/clap.cpp
     yycc/carton/binstore.cpp
+    yycc/carton/lexer61.cpp
     yycc/carton/fft.cpp
 )
 target_sources(YYCCTest
diff --git a/test/yycc/carton/lexer61.cpp b/test/yycc/carton/lexer61.cpp
new file mode 100644
index 0000000..1396ae5
--- /dev/null
+++ b/test/yycc/carton/lexer61.cpp
@@ -0,0 +1,166 @@
+#include <gtest/gtest.h>
+#include <yycc.hpp>
+#include <yycc/carton/lexer61.hpp>
+
+#define LEXER61 ::yycc::carton::lexer61
+
+namespace yycctest::carton::lexer61 {
+
+    TEST(CartonLexer61, EmptyCommand) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        EXPECT_TRUE(value.empty());
+    }
+
+    TEST(CartonLexer61, SingleArgument) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"program");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 1);
+        EXPECT_EQ(value[0], u8"program");
+    }
+
+    TEST(CartonLexer61, MultipleArguments) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"program arg1 arg2 arg3");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 4);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"arg1");
+        EXPECT_EQ(value[2], u8"arg2");
+        EXPECT_EQ(value[3], u8"arg3");
+    }
+
+    TEST(CartonLexer61, LeadingSpaces) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"   program arg");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 2);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"arg");
+    }
+
+    TEST(CartonLexer61, TrailingSpaces) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"program arg   ");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 2);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"arg");
+    }
+
+    TEST(CartonLexer61, EmbeddedSpaces) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"program    arg1     arg2");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 3);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"arg1");
+        EXPECT_EQ(value[2], u8"arg2");
+    }
+
+    TEST(CartonLexer61, SingleQuotedArgs) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"program 'arg with spaces' arg2");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 3);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"arg with spaces");
+        EXPECT_EQ(value[2], u8"arg2");
+    }
+
+    TEST(CartonLexer61, DoubleQuotedArgs) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8R"(program "arg with spaces" arg2)");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 3);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"arg with spaces");
+        EXPECT_EQ(value[2], u8"arg2");
+    }
+
+    TEST(CartonLexer61, MixedQuotes) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8R"(program "double quoted 'single inside'" 'single quoted "double inside"')");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 3);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"double quoted 'single inside'");
+        EXPECT_EQ(value[2], u8"single quoted \"double inside\"");
+    }
+
+    TEST(CartonLexer61, EscapedCharacters) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8R"(program escaped\ space "quoted with \" quote" 'single with \' quote')");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 4);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"escaped space");
+        EXPECT_EQ(value[2], u8"quoted with \" quote");
+        EXPECT_EQ(value[3], u8"single with \' quote");
+    }
+
+    TEST(CartonLexer61, ChineseCharacters) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8"程序 中文 参数");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 3);
+        EXPECT_EQ(value[0], u8"程序");
+        EXPECT_EQ(value[1], u8"中文");
+        EXPECT_EQ(value[2], u8"参数");
+    }
+
+    TEST(CartonLexer61, ChineseWithQuotes) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8R"(程序 "中文 参数" '另一个"引号"参数')");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 3);
+        EXPECT_EQ(value[0], u8"程序");
+        EXPECT_EQ(value[1], u8"中文 参数");
+        EXPECT_EQ(value[2], u8"另一个\"引号\"参数");
+    }
+
+    TEST(CartonLexer61, UnclosedQuoteError) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8R"(program "unclosed quote)");
+        ASSERT_FALSE(result.has_value());
+    }
+
+    TEST(CartonLexer61, EmptyArgumentInQuotes) {
+        LEXER61::Lexer61 lexer;
+        auto result = lexer.lex(u8R"(program "" '')");
+        ASSERT_TRUE(result.has_value());
+
+        auto value = std::move(result.value());
+        ASSERT_EQ(value.size(), 3);
+        EXPECT_EQ(value[0], u8"program");
+        EXPECT_EQ(value[1], u8"");
+        EXPECT_EQ(value[2], u8"");
+    }
+
+} // namespace yycctest::carton::lexer61
\ No newline at end of file