Add the first target and test

.gitignore

@@ -1,2 +1,3 @@
 /bazel-*
 cmake/build*
+Testing

CMakeLists.txt

@@ -16,10 +16,13 @@
 # 2022, and is our newest officially supported compiler.  The next CMake release was v3.23.0, on
 # March 29, 2022.  Therefore, our minimum version must be at least CMake 3.23.
 #
+# We also use the `CMAKE_VERIFY_INTERFACE_HEADER_SETS`, which was added in CMake
+# 3.24, which means the minimum must also be at least 3.24.
+#
 # The maximum version should be the latest version we've tested the project with.
 #
 # [1]: https://cliutils.gitlab.io/modern-cmake/chapters/intro/dodonot.html
-cmake_minimum_required(VERSION 3.23...3.29)
+cmake_minimum_required(VERSION 3.24...3.29)
 
 project(
    Au
@@ -28,3 +31,25 @@ project(
    HOMEPAGE_URL "https://aurora-opensource.github.io/au/0.3.4/"
    LANGUAGES CXX
 )
+
+enable_testing()
+
+# Bring in GoogleTest so we can build and run the tests.
+include(FetchContent)
+FetchContent_Declare(
+   googletest
+   GIT_REPOSITORY https://github.com/google/googletest.git
+   GIT_TAG 58d77fa8070e8cec2dc1ed015d66b454c8d78850 # Release 1.12.1
+   FIND_PACKAGE_ARGS
+      1.12.1
+      NAMES GTest
+)
+
+# https://google.github.io/googletest/quickstart-cmake.html
+# For Windows: Prevent overriding the parent project's compiler/linker settings
+set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+
+FetchContent_MakeAvailable(googletest)
+include(GoogleTest)
+
+add_subdirectory(au)

WORKSPACE

@@ -113,6 +113,7 @@ gcc_register_toolchain(
 http_archive(
     name = "com_google_googletest",
     sha256 = "24564e3b712d3eb30ac9a85d92f7d720f60cc0173730ac166f27dda7fed76cb2",
+    # NOTE: if updating this version, also update the version numbers in `CMakelists.txt`.
     strip_prefix = "googletest-release-1.12.1",
     urls = ["https://github.com/google/googletest/archive/refs/tags/release-1.12.1.zip"],
 )

au/CMakeLists.txt

@@ -0,0 +1,43 @@
+# Copyright 2024 Aurora Operations, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+cmake_path(GET CMAKE_CURRENT_SOURCE_DIR PARENT_PATH AU_BASE_DIRECTORY)
+
+#
+# Private implementation detail targets
+#
+
+add_library(stdx INTERFACE)
+target_sources(stdx
+   INTERFACE
+   FILE_SET HEADERS
+   BASE_DIRS ${AU_BASE_DIRECTORY}
+   FILES
+      stdx/experimental/is_detected.hh
+      stdx/functional.hh
+      stdx/type_traits.hh
+      stdx/utility.hh
+)
+
+add_executable(stdx_test)
+target_sources(stdx_test
+   PRIVATE
+      stdx/test/utility_test.cc
+)
+target_link_libraries(stdx_test
+   PRIVATE
+      stdx
+      GTest::gtest_main
+)
+gtest_discover_tests(stdx_test)

docs/install.md

@@ -257,10 +257,15 @@ To build the library using this experimental CMake support, follow these steps:
 ```sh
 # CMake is a "meta build system", not a build system.
 # This first command generates the actual build files.
-cmake -B cmake/build -S .
-
-# This command builds the library.
-cmake --build cmake/build
+cmake -S . -B cmake/build -DCMAKE_VERIFY_INTERFACE_HEADER_SETS=TRUE
+
+# This command builds Au, checks include paths, and runs unit tests.
+cmake \
+  --build cmake/build \
+  --target \
+    all \
+    all_verify_interface_header_sets \
+    test
 ```
 
 #### Other build systems (CMake / conan / vcpkg / ...)