diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index e8eb86e..b0a8210 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -49,7 +49,7 @@ jobs:
           apt install -y gcovr lcov
 
       - name: Configure
-        run: cmake -S test -B build -D CMAKE_BUILD_TYPE=Debug
+        run: cmake -S test -B build -D CMAKE_BUILD_TYPE=Debug -D CMAKE_CXX_FLAGS="-Wall -fprofile-arcs -ftest-coverage --coverage"
 
       - name: Build
         run: cmake --build build -j ${{steps.cores.outputs.count}}
@@ -62,7 +62,6 @@ jobs:
         run: |
           lcov -d . -c -o out.info --rc lcov_branch_coverage=1 --no-external
           lcov -e out.info '*include/ss*hpp' -o filtered.info
-          genhtml --t "SSP Coverage" --legend --demangle-cpp -o html -s --branch-coverage -p $PWD filtered.info
 
       - name: Invoke coveralls
         uses: coverallsapp/github-action@v2
diff --git a/ssp.hpp b/ssp.hpp
index e6fbdba..d50d3c3 100644
--- a/ssp.hpp
+++ b/ssp.hpp
@@ -2017,7 +2017,6 @@ private:
         return extract_tuple<Ts...>(elems);
     }
 
-    // do not know how to specialize by return type :(
     template <typename... Ts>
     no_void_validator_tup_t<std::tuple<Ts...>> convert_impl(
         const split_data& elems, const std::tuple<Ts...>*) {
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 94c3327..de6b612 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -12,8 +12,6 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
     target_compile_options(ssp INTERFACE -Wall -Wextra)
 endif()
 
-set(CMAKE_CXX_FLAGS "-Wall -fprofile-arcs -ftest-coverage --coverage")
-
 if (MSVC)
   add_compile_options(/bigobj)
 elseif (MINGW)
diff --git a/test/test_extractions.cpp b/test/test_extractions.cpp
index f1ba009..8b2b64b 100644
--- a/test/test_extractions.cpp
+++ b/test/test_extractions.cpp
@@ -64,8 +64,8 @@ TEST_CASE("extract test functions for numbers with invalid inputs") {
     CHECK_INVALID_CONVERSION("xxx1", float);
 
     // number too big
-    CHECK_INVALID_CONVERSION((std::string{20, '1'} + "." +
-                              std::string{20, '2'}),
+    CHECK_INVALID_CONVERSION((std::string{40, '1'} + "." +
+                              std::string{40, '2'}),
                              double);
 
     // random input for int
diff --git a/test/test_extractions_without_fast_float.cpp b/test/test_extractions_without_fast_float.cpp
index fbb9558..7e6660c 100644
--- a/test/test_extractions_without_fast_float.cpp
+++ b/test/test_extractions_without_fast_float.cpp
@@ -31,8 +31,8 @@ TEST_CASE("extract test functions for numbers with invalid inputs without fast "
     CHECK_INVALID_CONVERSION("xxx1", float);
 
     // number too big
-    CHECK_INVALID_CONVERSION((std::string{20, '1'} + "." +
-                              std::string{20, '2'}),
+    CHECK_INVALID_CONVERSION((std::string{40, '1'} + "." +
+                              std::string{40, '2'}),
                              double);
 }