Command pattern started

Added virtual base class and first implementation.

libs/CMakeLists.txt

@@ -1,4 +1,5 @@
 # other features
 set(CMAKE_CXX_CLANG_TIDY clang-tidy)
 
+add_subdirectory(common)
 add_subdirectory(cli)

libs/common/CMakeLists.txt

@@ -0,0 +1,8 @@
+add_library(common INTERFACE)
+target_include_directories(common INTERFACE include)
+
+add_executable(common_test src/command.test.cpp)
+target_link_libraries(common_test common gtest gmock gtest_main)
+
+include(GoogleTest)
+gtest_discover_tests(common_test)

libs/common/include/command.hpp

@@ -0,0 +1,27 @@
+/// \file
+/// \copyright SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <iostream>
+#include <string_view>
+
+namespace command {
+
+class Command {
+ public:
+  virtual ~Command() = default;
+  virtual void execute() const = 0;
+};
+
+class PrintCommand : public Command {
+ public:
+  explicit PrintCommand(std::string_view sv) : message{std::move(sv)} {}
+
+  void execute() const override { std::cout << message << std::endl; }
+
+ private:
+  std::string_view message;
+};
+
+}  // namespace command

libs/common/src/command.test.cpp

@@ -0,0 +1,16 @@
+/// \copyright SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "command.hpp"
+
+#include <gtest/gtest.h>
+
+namespace command {
+
+TEST(CommandTest, Initialization) {
+  const PrintCommand command{"Hi!"};
+
+  auto execute = [](const command::Command& cmd) { cmd.execute(); };
+  execute(command);
+}
+
+}  // namespace command