From 102bc1953f3a4fcbc20279cb22f907a310a88714 Mon Sep 17 00:00:00 2001
From: Chad Condon <chad@condon.tech>
Date: Tue, 31 Mar 2026 23:16:22 -0700
Subject: [PATCH] Automate coverage via CTest post-test hooks

Add cmake/lcov.cmake and cmake/CTestCustom.cmake.in so that lcov
capture, filtering, and genhtml run automatically as CTEST_CUSTOM_POST_TEST
hooks after ctest completes. Wire the coverage preset to load lcov.cmake
via CMAKE_PROJECT_CppUTest_INCLUDE, and update the CI workflow to drop
the manual lcov shell steps and point coverallsapp at the new output path
(cpputest_build/coverage.lcov).
---
 .github/workflows/basic.yml |  7 +------
 CMakePresets.json           |  1 +
 cmake/CTestCustom.cmake.in  |  6 ++++++
 cmake/lcov.cmake            | 13 +++++++++++++
 4 files changed, 21 insertions(+), 6 deletions(-)
 create mode 100644 cmake/CTestCustom.cmake.in
 create mode 100644 cmake/lcov.cmake

diff --git a/.github/workflows/basic.yml b/.github/workflows/basic.yml
index dd4615e08..de5c5d8ea 100644
--- a/.github/workflows/basic.yml
+++ b/.github/workflows/basic.yml
@@ -298,15 +298,10 @@ jobs:
           ctest --test-dir build
         if: ${{ matrix.install }}
 
-      - name: Coverage
-        run: |
-          lcov --ignore-errors mismatch --capture --directory . --no-external --output-file lcov.info
-          lcov --remove lcov.info --output-file lcov.info '*/tests/*'
-        if: ${{ matrix.name == 'Coverage' }}
       - name: Coveralls
         uses: coverallsapp/github-action@master
         with:
-          path-to-lcov: lcov.info
+          path-to-lcov: cpputest_build/coverage.lcov
           github-token: ${{ secrets.GITHUB_TOKEN }}
         if: ${{ matrix.name == 'Coverage' }}
 
diff --git a/CMakePresets.json b/CMakePresets.json
index a4a3f8327..7fffdefc0 100644
--- a/CMakePresets.json
+++ b/CMakePresets.json
@@ -81,6 +81,7 @@
       },
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug",
+        "CMAKE_PROJECT_CppUTest_INCLUDE": "${sourceDir}/cmake/lcov.cmake",
         "CMAKE_CXX_STANDARD": "11",
         "CPPUTEST_EXAMPLES": false
       }
diff --git a/cmake/CTestCustom.cmake.in b/cmake/CTestCustom.cmake.in
new file mode 100644
index 000000000..ebdac37c8
--- /dev/null
+++ b/cmake/CTestCustom.cmake.in
@@ -0,0 +1,6 @@
+set(CTEST_CUSTOM_POST_TEST
+    "@LCOV@ --capture --directory @CMAKE_BINARY_DIR@ --base-directory @CMAKE_SOURCE_DIR@ --no-external --ignore-errors mismatch,inconsistent --output-file @CMAKE_BINARY_DIR@/coverage.lcov"
+    "@LCOV@ --remove @CMAKE_BINARY_DIR@/coverage.lcov --output-file @CMAKE_BINARY_DIR@/coverage.lcov */tests/*"
+    "@CMAKE_COMMAND@ -E rm -rf @CMAKE_BINARY_DIR@/coverage"
+    "@GENHTML@ @CMAKE_BINARY_DIR@/coverage.lcov --output-directory @CMAKE_BINARY_DIR@/coverage"
+)
diff --git a/cmake/lcov.cmake b/cmake/lcov.cmake
new file mode 100644
index 000000000..ca2d02cb7
--- /dev/null
+++ b/cmake/lcov.cmake
@@ -0,0 +1,13 @@
+if(NOT CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+    message(FATAL_ERROR
+        "Coverage requires GCC or Clang (got ${CMAKE_CXX_COMPILER_ID})")
+endif()
+
+find_program(LCOV lcov REQUIRED)
+find_program(GENHTML genhtml REQUIRED)
+
+configure_file(
+    "${CMAKE_CURRENT_SOURCE_DIR}/cmake/CTestCustom.cmake.in"
+    "${CMAKE_BINARY_DIR}/CTestCustom.cmake"
+    @ONLY
+)