Issue reproduced.

Author: iwanders

test_filter.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+
+# Just for demo purposes... Probably don't want an in-tree build ;)
+mkdir -p build/
+cd build/
+cmake ../ -DPYBIND11_TEST_FILTER="test_smart_ptr.cpp;test_virtual_functions.cpp"
+cmake --build . --target check
+cd ../

tests/CMakeLists.txt

@@ -128,6 +128,7 @@ set(PYBIND11_TEST_FILES
     test_custom_type_casters
     test_custom_type_setup
     test_docstring_options
+    test_z.py
     test_eigen
     test_enum
     test_eval
@@ -212,6 +213,9 @@ foreach(test_name ${PYBIND11_TEST_FILES})
 endforeach()
 set(PYBIND11_TEST_FILES ${PYBIND11_CPPTEST_FILES})
 list(SORT PYBIND11_PYTEST_FILES)
+message("PYTEST ${PYBIND11_PYTEST_FILES}")
+message("PYBIND11_TEST_FILES ${PYBIND11_TEST_FILES}")
+
 
 # Contains the set of test files that require pybind11_cross_module_tests to be
 # built; if none of these are built (i.e. because TEST_OVERRIDE is used and