diff --git a/include/stdexec/__detail/__read_env.hpp b/include/stdexec/__detail/__read_env.hpp
index f8c79814b..b6fed2217 100644
--- a/include/stdexec/__detail/__read_env.hpp
+++ b/include/stdexec/__detail/__read_env.hpp
@@ -57,7 +57,7 @@ namespace STDEXEC
       }
 
       _Receiver       __rcvr_;
-      __optional<_Ty> __result_;
+      __optional<_Ty> __result_ = __nullopt;
     };
 
     template <class _Receiver, class _Query, class _Ty>
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index e76071294..c27c82700 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -14,6 +14,12 @@
 # limitations under the License.
 #=============================================================================
 
+function(add_compile_diagnostics TARGET)
+    if(CMAKE_CXX_COMPILER_ID STREQUAL Clang OR CMAKE_CXX_COMPILER_ID STREQUAL GNU)
+        target_compile_options(${TARGET} PRIVATE -Wall -Wextra -Wpedantic -Werror)
+    endif()
+endfunction()
+
 set(stdexec_test_sources
     test_main.cpp
     stdexec/cpos/test_cpo_bulk.cpp
@@ -97,6 +103,7 @@ target_link_libraries(common_test_settings INTERFACE $<TARGET_NAME_IF_EXISTS:TBB
 #     $<$<NOT:$<AND:$<CXX_COMPILER_ID:NVHPC>,$<COMPILE_LANGUAGE:CXX>>>:STDEXEC_ENABLE_EXTRA_TYPE_CHECKING>)
 
 add_executable(test.stdexec ${stdexec_test_sources})
+add_compile_diagnostics(test.stdexec)
 target_link_libraries(test.stdexec
     PUBLIC
     STDEXEC::stdexec
@@ -109,6 +116,7 @@ if(STDEXEC_BUILD_PARALLEL_SCHEDULER)
   add_executable(test.parallel_scheduler_replacement
                  test_main.cpp
                  stdexec/schedulers/test_parallel_scheduler_replacement.cpp)
+  add_compile_diagnostics(test.parallel_scheduler_replacement)
   target_link_libraries(test.parallel_scheduler_replacement
       PUBLIC
       STDEXEC::stdexec
@@ -120,6 +128,7 @@ if(STDEXEC_BUILD_PARALLEL_SCHEDULER)
 endif()
 
 add_executable(test.scratch test_main.cpp test_scratch.cpp)
+add_compile_diagnostics(test.scratch)
 target_link_libraries(test.scratch
     PUBLIC
     STDEXEC::stdexec
diff --git a/test/exec/CMakeLists.txt b/test/exec/CMakeLists.txt
index 3424dd3df..eefefde1f 100644
--- a/test/exec/CMakeLists.txt
+++ b/test/exec/CMakeLists.txt
@@ -68,6 +68,7 @@ set_source_files_properties(test_any_sender.cpp
     COMPILE_FLAGS $<$<CXX_COMPILER_ID:MSVC>:/bigobj>)
 
 add_executable(test.exec ${exec_test_sources})
+add_compile_diagnostics(test.exec)
 target_link_libraries(test.exec
     PUBLIC
     STDEXEC::stdexec
diff --git a/test/test_common/scope_helpers.hpp b/test/test_common/scope_helpers.hpp
index d826e2996..ab87e8e36 100644
--- a/test/test_common/scope_helpers.hpp
+++ b/test/test_common/scope_helpers.hpp
@@ -56,7 +56,7 @@ namespace
       -> ex::completion_signatures_of_t<ex::__child_of<std::remove_cvref_t<Sender>>, Env...>
     {
       return {};
-    };
+    }
   };
 
   struct counting_resource : std::pmr::memory_resource