test: Add CMake subproject example and test

examples/use_cmake_subproject/CMakeLists.txt

@@ -0,0 +1,17 @@
+# intx: extended precision integer library.
+# Copyright 2019-2020 Pawel Bylica.
+# Licensed under the Apache License, Version 2.0.
+
+# This example shows how to use intx CMake subproject.
+
+cmake_minimum_required(VERSION 3.10)
+
+project(use_intx_cmake_subproject LANGUAGES CXX)
+
+add_subdirectory(intx)
+
+add_executable(use_int128 use_int128.cpp)
+target_link_libraries(use_int128 PRIVATE intx::int128)
+
+add_executable(use_intx use_intx.cpp)
+target_link_libraries(use_intx PRIVATE intx::intx)

examples/use_cmake_subproject/intx/.gitignore

@@ -0,0 +1,3 @@
+*
+!/.gitignore
+!/COPY_INTX_HERE

examples/use_cmake_subproject/use_int128.cpp

@@ -0,0 +1,10 @@
+// intx: extended precision integer library.
+// Copyright 2019-2020 Pawel Bylica.
+// Licensed under the Apache License, Version 2.0.
+
+#include <intx/int128.hpp>
+
+int main(int argc, char**)
+{
+    return static_cast<int>(argc / intx::uint128{1, 0});
+}

examples/use_cmake_subproject/use_intx.cpp

@@ -0,0 +1,10 @@
+// intx: extended precision integer library.
+// Copyright 2019-2020 Pawel Bylica.
+// Licensed under the Apache License, Version 2.0.
+
+#include <intx/intx.hpp>
+
+int main(int argc, char**)
+{
+    return static_cast<int>(intx::uint512{argc} / (intx::uint512{1} << 111));
+}

test/integration/CMakeLists.txt

@@ -1,5 +1,6 @@
 # intx: extended precision integer library.
-# Copyright 2019 Pawel Bylica.
+# Copyright 2019-2020 Pawel Bylica.
 # Licensed under the Apache License, Version 2.0.
 
 add_subdirectory(cmake_package)
+add_subdirectory(cmake_subproject)

test/integration/cmake_subproject/CMakeLists.txt

@@ -0,0 +1,30 @@
+# intx: extended precision integer library.
+# Copyright 2020 Pawel Bylica.
+# Licensed under the Apache License, Version 2.0.
+
+# Test suite for using intx as a CMake subproject.
+
+# All files needed to build intx as a CMake subproject:
+file(
+    COPY
+    ${PROJECT_SOURCE_DIR}/CMakeLists.txt
+    ${PROJECT_SOURCE_DIR}/cmake
+    ${PROJECT_SOURCE_DIR}/include
+    DESTINATION ${PROJECT_SOURCE_DIR}/examples/use_cmake_subproject/intx
+)
+
+set(build_dir ${CMAKE_CURRENT_BINARY_DIR}/build)
+file(MAKE_DIRECTORY ${build_dir})
+
+if(CMAKE_BUILD_TYPE)
+    set(build_type_arg -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE})
+endif()
+
+add_test(
+    NAME ${PROJECT_NAME}/cmake_subproject/use_cmake_subproject
+    COMMAND
+    ${CMAKE_COMMAND} -G ${CMAKE_GENERATOR}
+    ${PROJECT_SOURCE_DIR}/examples/use_cmake_subproject
+    ${build_type_arg}
+    WORKING_DIRECTORY ${build_dir}
+)