diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 0000000..36821a3
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,25 @@
+cmake_minimum_required(VERSION 3.10.0)
+project(test_test_123)
+include(FetchContent)
+if (MSVC)
+    add_compile_options(/utf-8)
+endif()
+FetchContent_Declare(
+  googletest
+  URL https://github.com/google/googletest/archive/03597a01ee50ed33e9dfd640b249b4be3799d395.zip
+)
+# For Windows: Prevent overriding the parent project's compiler/linker settings
+set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+FetchContent_MakeAvailable(googletest)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/../include)
+
+include(CTest)
+enable_testing()
+
+add_executable(test_test_123 test_adapter.cpp ../src/adapter.cpp)
+
+target_link_libraries(test_test_123 gtest gmock gtest_main)
+include(GoogleTest)
+gtest_discover_tests(test_test_123)
\ No newline at end of file
diff --git a/tests/test_adapter.cpp b/tests/test_adapter.cpp
new file mode 100644
index 0000000..3239a79
--- /dev/null
+++ b/tests/test_adapter.cpp
@@ -0,0 +1,89 @@
+#include <gtest/gtest.h>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+#include "adapter.hpp"
+
+class StdoutCapture {
+public:
+    StdoutCapture() {
+        old_buf_ = std::cout.rdbuf();
+        std::cout.rdbuf(buffer_.rdbuf());
+    }
+    ~StdoutCapture() { std::cout.rdbuf(old_buf_); }
+    std::string GetOutput() const { return buffer_.str(); }
+private:
+    std::ostringstream buffer_;
+    std::streambuf* old_buf_;
+};
+
+class CommandLineAdapterTest : public ::testing::Test {
+protected:
+    std::vector<char*> CreateArgv(const std::vector<std::string>& args) {
+        std::vector<char*> argv;
+        for (const auto& arg : args) {
+            argv.push_back(const_cast<char*>(arg.c_str()));
+        }
+        return argv;
+    }
+};
+
+TEST_F(CommandLineAdapterTest, testCommandLineAdapterNormalInput) {
+    std::vector<std::string> args = {"app", "--help"};
+    auto argv = CreateArgv(args);
+    CommandLineAdapter adapter(static_cast<int>(args.size()), argv.data());
+    CommandLineArgs result = adapter.parse();
+    EXPECT_TRUE(result.show_help);
+    EXPECT_FALSE(result.has_errors);
+}
+
+TEST_F(CommandLineAdapterTest, testParseConfigMissingValueException) {
+    std::vector<std::string> args = {"app", "--config"};
+    auto argv = CreateArgv(args);
+    CommandLineAdapter adapter(static_cast<int>(args.size()), argv.data());
+    CommandLineArgs result = adapter.parse();
+    EXPECT_TRUE(result.has_errors);
+    EXPECT_EQ(result.error_msg, "Missing value for --config");
+}
+
+TEST_F(CommandLineAdapterTest, testParseUnknownArgumentException) {
+    std::vector<std::string> args = {"app", "--unknown"};
+    auto argv = CreateArgv(args);
+    CommandLineAdapter adapter(static_cast<int>(args.size()), argv.data());
+    CommandLineArgs result = adapter.parse();
+    EXPECT_TRUE(result.has_errors);
+    EXPECT_EQ(result.error_msg, "Unknown argument: --unknown");
+}
+
+TEST_F(CommandLineAdapterTest, testParseMultipleFlagsNormal) {
+    std::vector<std::string> args = {"app", "--config", "cfg.ini", "--version"};
+    auto argv = CreateArgv(args);
+    CommandLineAdapter adapter(static_cast<int>(args.size()), argv.data());
+    CommandLineArgs result = adapter.parse();
+    EXPECT_EQ(result.config_path, "cfg.ini");
+    EXPECT_TRUE(result.show_version);
+    EXPECT_FALSE(result.has_errors);
+}
+
+TEST_F(CommandLineAdapterTest, testPrintHelpSpecialScenario) {
+    StdoutCapture capture;
+    std::vector<std::string> args = {"app"};
+    auto argv = CreateArgv(args);
+    CommandLineAdapter adapter(static_cast<int>(args.size()), argv.data());
+    adapter.printHelp();
+    std::string output = capture.GetOutput();
+    EXPECT_NE(output.find("ModularApp v1.0.0"), std::string::npos);
+    EXPECT_NE(output.find("--config"), std::string::npos);
+    EXPECT_NE(output.find("--help"), std::string::npos);
+}
+
+TEST_F(CommandLineAdapterTest, testPrintVersionSpecialScenario) {
+    StdoutCapture capture;
+    std::vector<std::string> args = {"app"};
+    auto argv = CreateArgv(args);
+    CommandLineAdapter adapter(static_cast<int>(args.size()), argv.data());
+    adapter.printVersion();
+    std::string output = capture.GetOutput();
+    EXPECT_EQ(output, "ModularApp version 1.0.0\n");
+}
\ No newline at end of file