Add fetch content test

Author: eel76-hmi

CMakeLists.txt

@@ -12,21 +12,15 @@ target_sources(traits INTERFACE
   FILES "${CMAKE_CURRENT_SOURCE_DIR}/include/traits.h"
   )
 
+# only proceed if we are building the library directly
+
 if(NOT CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
     return()
 endif()
 
 option(TRAITS_BUILD_EXAMPLES "whether or not examples should be built" ON)
 option(TRAITS_BUILD_TESTS "whether or not tests should be built" ON)
-
-if(TRAITS_BUILD_EXAMPLES)
-    add_subdirectory(examples)
-endif()
-
-if(TRAITS_BUILD_TESTS)
-    enable_testing()
-    add_subdirectory(tests)
-endif()
+set(TRAITS_PACKAGE_NAME "${PROJECT_NAME}.zip" CACHE FILEPATH "name of package file")
 
 # installation rules
 
@@ -39,15 +33,27 @@ install(FILES "cmake/traits-config.cmake" "${CMAKE_CURRENT_BINARY_DIR}/traits-co
 
 # downloadable package for fetch content
 
-set (package_name "${PROJECT_NAME}.zip")
 add_custom_command(
-    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${package_name}"
-    COMMAND ${CMAKE_COMMAND} -E tar c "${CMAKE_CURRENT_BINARY_DIR}/${package_name}" --format=zip --
+    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${TRAITS_PACKAGE_NAME}"
+    COMMAND ${CMAKE_COMMAND} -E tar c "${CMAKE_CURRENT_BINARY_DIR}/${TRAITS_PACKAGE_NAME}" --format=zip --
     cmake/ examples/ include/ tests/ CMakeLists.txt LICENSE README.md
     WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
     )
 add_custom_command(
     OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/package_name"
-    COMMAND ${CMAKE_COMMAND} -E echo "name=${package_name}" > "${CMAKE_CURRENT_BINARY_DIR}/package_name"
+    COMMAND ${CMAKE_COMMAND} -E echo "name=${TRAITS_PACKAGE_NAME}" > "${CMAKE_CURRENT_BINARY_DIR}/package_name"
     )
-add_custom_target(package DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/${package_name}" "${CMAKE_CURRENT_BINARY_DIR}/package_name")
+add_custom_target(package DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/${TRAITS_PACKAGE_NAME}" "${CMAKE_CURRENT_BINARY_DIR}/package_name")
+
+# optional examples
+
+if(TRAITS_BUILD_EXAMPLES)
+    add_subdirectory(examples)
+endif()
+
+# optional tests
+
+if(TRAITS_BUILD_TESTS)
+    enable_testing()
+    add_subdirectory(tests)
+endif()

tests/CMakeLists.txt

@@ -28,12 +28,12 @@ endforeach()
 # Add the deployment test, which checks that we can indeed install traits and
 # then use `find_package` to depend on it from another CMake project.
 include(ExternalProject)
-set(TRAITS_FAKE_INSTALL_DIR "${PROJECT_BINARY_DIR}/fakeroot")
+set(FAKE_INSTALL_DIR "${PROJECT_BINARY_DIR}/fakeroot")
 ExternalProject_Add(test.deploy.fakeroot
   SOURCE_DIR "${PROJECT_SOURCE_DIR}"
   EXCLUDE_FROM_ALL TRUE
   BUILD_ALWAYS TRUE
-  INSTALL_DIR "${TRAITS_FAKE_INSTALL_DIR}"
+  INSTALL_DIR "${FAKE_INSTALL_DIR}"
   CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
              -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
              -DCMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH}
@@ -49,8 +49,25 @@ add_custom_target(test.deploy
   COMMAND ${CMAKE_COMMAND} -E chdir "${CMAKE_CURRENT_BINARY_DIR}/deploy"
             ${CMAKE_COMMAND} "${CMAKE_CURRENT_SOURCE_DIR}/deploy"
                              -DCMAKE_CXX_COMPILER="${CMAKE_CXX_COMPILER}"
-                             -DCMAKE_PREFIX_PATH="${CMAKE_PREFIX_PATH}\;${TRAITS_FAKE_INSTALL_DIR}"
+                             -DCMAKE_PREFIX_PATH="${CMAKE_PREFIX_PATH}\;${FAKE_INSTALL_DIR}"
                              -DCMAKE_TOOLCHAIN_FILE=${CMAKE_TOOLCHAIN_FILE}
   COMMAND ${CMAKE_COMMAND} --build "${CMAKE_CURRENT_BINARY_DIR}/deploy"
 )
 add_test(NAME test.deploy COMMAND ${CMAKE_COMMAND} --build "${PROJECT_BINARY_DIR}" --target test.deploy)
+
+# Add the fetch test, which checks that we can indeed use fetch content
+# from another CMake project.
+
+add_custom_target(test.fetch
+  DEPENDS package
+  COMMAND ${CMAKE_COMMAND} -E remove_directory "${CMAKE_CURRENT_BINARY_DIR}/fetch"
+  COMMAND ${CMAKE_COMMAND} -E make_directory "${CMAKE_CURRENT_BINARY_DIR}/fetch"
+  COMMAND ${CMAKE_COMMAND} -S "${CMAKE_CURRENT_SOURCE_DIR}/fetch"
+                           -B "${CMAKE_CURRENT_BINARY_DIR}/fetch"
+                             -DPACKAGE_PATH="${CMAKE_CURRENT_BINARY_DIR}/../${TRAITS_PACKAGE_NAME}"
+                             -DCMAKE_CXX_COMPILER="${CMAKE_CXX_COMPILER}"
+                             -DCMAKE_PREFIX_PATH="${CMAKE_PREFIX_PATH}"
+                             -DCMAKE_TOOLCHAIN_FILE="${CMAKE_TOOLCHAIN_FILE}"
+  COMMAND ${CMAKE_COMMAND} --build "${CMAKE_CURRENT_BINARY_DIR}/fetch"
+)
+add_test(NAME test.fetch COMMAND ${CMAKE_COMMAND} --build "${PROJECT_BINARY_DIR}" --target test.fetch)

tests/deploy/CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.0)
-project(external CXX)
+project(deploy CXX)
 find_package(traits REQUIRED)
 
 add_executable(main main.cpp)

tests/fetch/CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.24)
+project(fetch CXX)
+
+if(NOT DEFINED PACKAGE_PATH)
+    message(FATAL_ERROR "PACKAGE_PATH is required. Please set -DPACKAGE_PATH=/path/to/package.zip")
+endif()
+
+if(NOT EXISTS "${PACKAGE_PATH}")
+    message(FATAL_ERROR "Package file not found at: ${PACKAGE_PATH}")
+endif()
+
+include(FetchContent)
+FetchContent_Declare(traits URL "${PACKAGE_PATH}")
+FetchContent_MakeAvailable(traits)
+
+add_executable(main main.cpp)
+target_link_libraries(main Traits::traits)

tests/fetch/main.cpp

@@ -0,0 +1,4 @@
+#include <traits.h>
+using namespace traits;
+
+int main() { return 0; }