diff --git a/tests/test_class_sh_trampoline_self_life_support.cpp b/tests/test_class_sh_trampoline_self_life_support.cpp
index 9b67323f3a..859b9f8fbc 100644
--- a/tests/test_class_sh_trampoline_self_life_support.cpp
+++ b/tests/test_class_sh_trampoline_self_life_support.cpp
@@ -10,7 +10,8 @@
 #include <string>
 #include <utility>
 
-namespace {
+namespace pybind11_tests {
+namespace class_sh_trampoline_self_life_support {
 
 struct Big5 { // Also known as "rule of five".
     std::string history;
@@ -43,7 +44,10 @@ struct Big5Trampoline : Big5, py::trampoline_self_life_support {
 };
 #endif
 
-} // namespace
+} // namespace class_sh_trampoline_self_life_support
+} // namespace pybind11_tests
+
+using namespace pybind11_tests::class_sh_trampoline_self_life_support;
 
 PYBIND11_SMART_HOLDER_TYPE_CASTERS(Big5)
 
diff --git a/tests/test_class_sh_trampoline_unique_ptr.cpp b/tests/test_class_sh_trampoline_unique_ptr.cpp
index af0fb16efc..13dc27b049 100644
--- a/tests/test_class_sh_trampoline_unique_ptr.cpp
+++ b/tests/test_class_sh_trampoline_unique_ptr.cpp
@@ -9,7 +9,7 @@
 #include <cstdint>
 
 namespace pybind11_tests {
-namespace class_sh_trampoline_basic {
+namespace class_sh_trampoline_unique_ptr {
 
 class Class {
 public:
@@ -31,6 +31,14 @@ class Class {
     std::uint64_t val_ = 0;
 };
 
+} // namespace class_sh_trampoline_unique_ptr
+} // namespace pybind11_tests
+
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_trampoline_unique_ptr::Class)
+
+namespace pybind11_tests {
+namespace class_sh_trampoline_unique_ptr {
+
 #ifdef PYBIND11_HAVE_INTERNALS_WITH_SMART_HOLDER_SUPPORT
 class PyClass : public Class, public py::trampoline_self_life_support {
 public:
@@ -42,13 +50,9 @@ class PyClass : public Class, public py::trampoline_self_life_support {
 };
 #endif
 
-} // namespace class_sh_trampoline_basic
+} // namespace class_sh_trampoline_unique_ptr
 } // namespace pybind11_tests
 
-using namespace pybind11_tests::class_sh_trampoline_basic;
-
-PYBIND11_SMART_HOLDER_TYPE_CASTERS(Class)
-
 TEST_SUBMODULE(class_sh_trampoline_unique_ptr, m) {
     m.attr("defined_PYBIND11_HAVE_INTERNALS_WITH_SMART_HOLDER_SUPPORT") =
 #ifndef PYBIND11_HAVE_INTERNALS_WITH_SMART_HOLDER_SUPPORT
@@ -56,6 +60,8 @@ TEST_SUBMODULE(class_sh_trampoline_unique_ptr, m) {
 #else
         true;
 
+    using namespace pybind11_tests::class_sh_trampoline_unique_ptr;
+
     py::classh<Class, PyClass>(m, "Class")
         .def(py::init<>())
         .def("set_val", &Class::setVal)
diff --git a/tests/test_class_sh_virtual_py_cpp_mix.cpp b/tests/test_class_sh_virtual_py_cpp_mix.cpp
index f85c87b27b..a68cb76aa3 100644
--- a/tests/test_class_sh_virtual_py_cpp_mix.cpp
+++ b/tests/test_class_sh_virtual_py_cpp_mix.cpp
@@ -50,9 +50,11 @@ struct CppDerivedVirtualOverrider : CppDerived, py::trampoline_self_life_support
 } // namespace class_sh_virtual_py_cpp_mix
 } // namespace pybind11_tests
 
-PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_virtual_py_cpp_mix::Base)
-PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_virtual_py_cpp_mix::CppDerivedPlain)
-PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::class_sh_virtual_py_cpp_mix::CppDerived)
+using namespace pybind11_tests::class_sh_virtual_py_cpp_mix;
+
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(Base)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(CppDerivedPlain)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(CppDerived)
 
 TEST_SUBMODULE(class_sh_virtual_py_cpp_mix, m) {
     m.attr("defined_PYBIND11_HAVE_INTERNALS_WITH_SMART_HOLDER_SUPPORT") =
@@ -61,8 +63,6 @@ TEST_SUBMODULE(class_sh_virtual_py_cpp_mix, m) {
 #else
         true;
 
-    using namespace pybind11_tests::class_sh_virtual_py_cpp_mix;
-
     py::classh<Base, BaseVirtualOverrider>(m, "Base").def(py::init<>()).def("get", &Base::get);
 
     py::classh<CppDerivedPlain, Base>(m, "CppDerivedPlain").def(py::init<>());