CI: build in-tree smoke tests and run them via CTest on all platforms

New tools/tests/ target (networkml_smoke) exercises the whole public API:
44 offline checks for Auth/Url/File/Chat-state/object construction, plus
26 live HTTP checks against postman-echo.com covering every Requests
verb, download with progress, and multipart upload. Gated behind
NETWORKML_BUILD_TESTS=ON so downstream consumers never build it.

CI configures with -DNETWORKML_BUILD_TESTS=ON on Linux, macOS, and
Windows, then runs ctest with NETWORKML_LIVE=1 so the HTTP verbs are
actually exercised (not just linked). Live Chat coverage stays opt-in
via NETWORKML_CHAT_PROVIDER/MODEL so no credentials are required.

Motivates: the CMake-config find_dependency bug found earlier this
session shipped past CI because the workflow only compiled + installed
the library, never running a real consumer. This closes that gap.

Author: meta-legend

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
       # --- configure ---
       - name: Configure (Linux/macOS, system packages)
         if: runner.os != 'Windows'
-        run: cmake -B build -S . -DCMAKE_BUILD_TYPE=Release
+        run: cmake -B build -S . -DCMAKE_BUILD_TYPE=Release -DNETWORKML_BUILD_TESTS=ON
 
       # Cache vcpkg's built-package archives so curl/nlohmann-json are not
       # rebuilt from source on every run. vcpkg's old x-gha backend was
@@ -55,11 +55,19 @@ jobs:
           git -C "$env:VCPKG_INSTALLATION_ROOT" fetch --depth 1 origin $base
           git -C "$env:VCPKG_INSTALLATION_ROOT" checkout -f $base
           & "$env:VCPKG_INSTALLATION_ROOT\bootstrap-vcpkg.bat" -disableMetrics
-          cmake -B build -S . "-DCMAKE_TOOLCHAIN_FILE=$env:VCPKG_INSTALLATION_ROOT/scripts/buildsystems/vcpkg.cmake"
+          cmake -B build -S . "-DCMAKE_TOOLCHAIN_FILE=$env:VCPKG_INSTALLATION_ROOT/scripts/buildsystems/vcpkg.cmake" -DNETWORKML_BUILD_TESTS=ON
 
-      # --- build + verify install/export ---
+      # --- build + test + verify install/export ---
       - name: Build
         run: cmake --build build --config Release
 
+      # Smoke tests. Live HTTP is enabled on all runners; live Chat is skipped
+      # unless NETWORKML_CHAT_PROVIDER + NETWORKML_CHAT_MODEL are set (opt-in).
+      - name: Test
+        working-directory: build
+        env:
+          NETWORKML_LIVE: "1"
+        run: ctest -C Release --output-on-failure
+
       - name: Install (verify export)
         run: cmake --install build --config Release --prefix "${{ runner.temp }}/nml-install"

CMakeLists.txt

@@ -74,6 +74,14 @@ install(FILES
     DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/NetworkML
 )
 
+# Optional in-tree smoke tests (built only when explicitly requested, so downstream
+# consumers via add_subdirectory / FetchContent never build them by default).
+option(NETWORKML_BUILD_TESTS "Build the Network ML smoke tests (tools/tests)" OFF)
+if(NETWORKML_BUILD_TESTS)
+    enable_testing()
+    add_subdirectory(tools/tests)
+endif()
+
 # Building, installing, and consuming instructions for this library are as follows:
 #
 #   Build:

tools/tests/CMakeLists.txt

@@ -0,0 +1,8 @@
+# Smoke test target, driven by CTest. Built only when NETWORKML_BUILD_TESTS=ON;
+# consumers of the library never see this.
+add_executable(networkml_smoke main.cpp)
+target_link_libraries(networkml_smoke PRIVATE networkml)
+
+add_test(NAME smoke COMMAND networkml_smoke)
+# Keep the whole run under two minutes even if postman-echo is slow.
+set_tests_properties(smoke PROPERTIES TIMEOUT 120)