add cli application class

fix::cli::app processes the command line arguments and outputs results
on the console. First unit test checks for usage output on erroneous
arguments

CMakeLists.txt

@@ -50,7 +50,6 @@ add_subdirectory(src)
 
 if (ENABLE_TESTING)
   enable_testing()
-  message("Building Tests. Be sure to check out test/constexpr_tests for constexpr testing")
   add_subdirectory(test)
 endif ()
 

src/CMakeLists.txt

@@ -8,3 +8,5 @@ target_link_libraries(
     project_warnings
     CONAN_PKG::fmt
 )
+
+add_subdirectory(fix_cli)

src/fix_cli/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(FIX_CLI_SOURCES
+    app.cpp
+    )
+
+
+add_library(fix_cli ${FIX_CLI_SOURCES})
+target_link_libraries(fix_cli PRIVATE project_warnings project_options)
+target_include_directories(fix_cli PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)

src/fix_cli/app.cpp

@@ -0,0 +1,25 @@
+#include "app.hpp"
+
+#include <ostream>
+
+using namespace fix::cli;
+using namespace std::string_view_literals;
+
+namespace {
+constexpr auto USAGE = R"(usage: fix [--help] <command> [<args>]
+
+Available commands:
+   create        Create a new issue
+   setstatus     Set the status of an issue
+   list          List all existing issues
+   show          Show a specific issue
+)"sv;
+}
+
+app::app(std::ostream &out)
+{
+  out << USAGE;
+}
+
+void app::run(const std::vector<std::string_view>& /*args*/) { //NOLINT
+}

src/fix_cli/app.hpp

@@ -0,0 +1,19 @@
+#ifndef FIX_APP_HPP
+#define FIX_APP_HPP
+
+#include <iosfwd>
+#include <string_view>
+#include <vector>
+
+namespace fix::cli {
+
+class app {
+public:
+  explicit app(std::ostream &out);
+
+  void run(std::vector<std::string_view> const &);
+};
+
+}
+
+#endif //FIX_APP_HPP

test/CMakeLists.txt

@@ -9,3 +9,5 @@ add_library(catch_main STATIC catch_main.cpp)
 target_link_libraries(catch_main PUBLIC CONAN_PKG::catch2)
 target_link_libraries(catch_main PRIVATE project_options)
 
+add_subdirectory(fix_cli)
+

test/fix_cli/CMakeLists.txt

@@ -0,0 +1,6 @@
+set(FIX_CLI_TEST_SOURCES
+    app_test.cpp
+    )
+
+add_executable(fix_cli_tests ${FIX_CLI_TEST_SOURCES})
+target_link_libraries(fix_cli_tests PRIVATE project_warnings project_options catch_main fix_cli)

test/fix_cli/app_test.cpp

@@ -0,0 +1,34 @@
+#include <catch2/catch.hpp>
+
+#include <sstream>
+#include <string_view>
+
+#include "app.hpp"
+
+using namespace std::literals;
+
+namespace {
+constexpr auto USAGE = R"(usage: fix [--help] <command> [<args>]
+
+Available commands:
+   create        Create a new issue
+   setstatus     Set the status of an issue
+   list          List all existing issues
+   show          Show a specific issue
+)"sv;
+}
+
+TEST_CASE("Prints usage and commands...") {
+  std::stringstream out;
+  fix::cli::app app{out};
+
+  SECTION("... when run without commands") {
+    app.run({});
+  }SECTION("... when run with --help option") {
+    app.run({"--help"});
+  }SECTION("... when run with -h option") {
+    app.run({"-h"});
+  }
+
+  CHECK(out.str() == USAGE);
+}