Improve test coverage to 100% functions / 88% lines; automate Windows coverage via OpenCppCoverage

.gitignore

@@ -1,2 +1,4 @@
 lib/*
 build/*
+CoverageReport-*/
+LastCoverageResults.log

build.sh

@@ -58,19 +58,57 @@ if [ "${COVERAGE}" = "ON" ]; then
     echo "Running unit tests..."
     BUILD_DIR="$(pwd)/build"
     (cd "${BUILD_DIR}" && ctest --output-on-failure) || { echo "Tests failed."; exit 1; }
-    
+
     echo "Tests passed. Generating coverage report..."
     COVERAGE_DIR="${BUILD_DIR}/coverage"
-    mkdir -p ${COVERAGE_DIR}
-
-    lcov --directory "${BUILD_DIR}" --capture --output-file ${COVERAGE_DIR}/coverage.info \
-        --rc branch_coverage=1 --exclude '/usr/*' --exclude '*/tests/*' --exclude '*/_deps/*' \
-        --quiet
-
-    genhtml --output-directory ${COVERAGE_DIR}/html --title "Event Loop Code Coverage" \
-            --prefix "${PWD}" --rc branch_coverage=1 --quiet ${COVERAGE_DIR}/coverage.info
-
-    echo "Coverage report generated at: ${COVERAGE_DIR}/html/index.html"
+    mkdir -p "${COVERAGE_DIR}"
+
+    OS="$(uname -s)"
+    if [[ "${OS}" == MINGW* ]] || [[ "${OS}" == MSYS* ]] || [[ "${OS}" == CYGWIN* ]]; then
+        # ── Windows: OpenCppCoverage ──────────────────────────────────────────
+        if ! command -v OpenCppCoverage &>/dev/null; then
+            echo "WARNING: OpenCppCoverage not found on PATH. Skipping Windows coverage report."
+            echo "Install it with: winget install OpenCppCoverage"
+        else
+            # Support both multi-config generators (MSVC) and single-config (Ninja/MinGW).
+            # Multi-config puts binaries under build/tests/<BuildType>/; single-config does not.
+            if [ -f "${BUILD_DIR}/tests/${BUILD_TYPE}/EventLoopTests.exe" ]; then
+                TEST_EXE="${BUILD_DIR}/tests/${BUILD_TYPE}/EventLoopTests.exe"
+                LIB_DLL="${BUILD_DIR}/${BUILD_TYPE}/EventLoop.dll"
+            else
+                TEST_EXE="${BUILD_DIR}/tests/EventLoopTests.exe"
+                LIB_DLL="${BUILD_DIR}/EventLoop.dll"
+            fi
+
+            echo "Generating Windows coverage report with OpenCppCoverage..."
+            OpenCppCoverage \
+                --sources "${PWD}/src" \
+                --sources "${PWD}/include" \
+                --modules "${LIB_DLL}" \
+                --export_type "html:${COVERAGE_DIR}/html" \
+                --export_type "cobertura:${COVERAGE_DIR}/coverage.xml" \
+                -- "${TEST_EXE}"
+
+            echo "Coverage report generated at: ${COVERAGE_DIR}/html/index.html"
+        fi
+    else
+        # ── Linux / macOS: lcov + genhtml ─────────────────────────────────────
+        # --ignore-errors unused: suppresses harmless warning when _deps/ does not
+        # exist (e.g. when gtest is installed system-wide instead of via FetchContent)
+        lcov --directory "${BUILD_DIR}" --capture \
+            --output-file "${COVERAGE_DIR}/coverage.info" \
+            --rc branch_coverage=1 \
+            --exclude '/usr/*' --exclude '*/tests/*' --exclude '*/_deps/*' \
+            --ignore-errors mismatch,empty,unused \
+            --quiet
+
+        genhtml --output-directory "${COVERAGE_DIR}/html" \
+                --title "Event Loop Code Coverage" \
+                --prefix "${PWD}" --rc branch_coverage=1 --quiet \
+                "${COVERAGE_DIR}/coverage.info"
+
+        echo "Coverage report generated at: ${COVERAGE_DIR}/html/index.html"
+    fi
 fi
 
 if [ ${TARGET} = "clean" ]; then
@@ -80,4 +118,4 @@ if [ ${TARGET} = "clean" ]; then
     if [ -d ${PWD}/lib ]; then
         rm -rf lib/*
     fi
-fi
+fi

src/EventManager.cpp

@@ -143,6 +143,15 @@ void EventManager::start()
 {
     try
     {
+        // A previous run's threads may still be joinable here (stop() signals
+        // shutdown but does not join). Reassigning a std::thread that already
+        // represents a joinable thread calls std::terminate(), so clean those
+        // up first to allow the loop to be safely restarted after a Halt().
+        if (m_mainLoop.joinable())
+            m_mainLoop.join();
+        if (m_scheduler.joinable())
+            m_scheduler.join();
+
         m_shutdown = false;
         m_scheduler = std::thread(&EventManager::eventScheduler, this);
         if (m_blockPrimary)