diff --git a/nanobind-2.6.1-test-build.patch b/nanobind-2.6.1-test-build.patch
new file mode 100644
index 0000000..9f99160
--- /dev/null
+++ b/nanobind-2.6.1-test-build.patch
@@ -0,0 +1,66 @@
+
+bugzilla.opensuse.org/show_bug.cgi?id=1239153
+github.com/wjakob/nanobind/issues/970
+github.com/wjakob/nanobind/commit/f2b08c9
+
+edited to fit file version from distribution
+
+
+From f2b08c936ec4b1dd06d374fef2637d89daa905f4 Mon Sep 17 00:00:00 2001
+From: Wenzel Jakob <wenzel.jakob@epfl.ch>
+Date: Tue, 8 Apr 2025 10:57:30 +0900
+Subject: [PATCH] fix parallel test suite build race condition
+
+---
+ tests/CMakeLists.txt | 16 +++++++++-------
+ 1 file changed, 9 insertions(+), 7 deletions(-)
+
+diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
+index 40ed1276..3bd54783 100644
+--- a/tests/CMakeLists.txt
++++ b/tests/CMakeLists.txt
+@@ -92,14 +92,22 @@ endforeach()
+ 
+ target_sources(test_intrusive_ext PRIVATE test_intrusive_impl.cpp)
+ 
++if (CMAKE_CONFIGURATION_TYPES)
++  set(OUT_DIR ${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>)
++else()
++  set(OUT_DIR ${CMAKE_CURRENT_BINARY_DIR})
++endif()
++
+ foreach (NAME functions classes ndarray stl enum typing make_iterator)
+   if (NAME STREQUAL typing)
+     set(EXTRA
+       MARKER_FILE py.typed
+       PATTERN_FILE "${CMAKE_CURRENT_SOURCE_DIR}/pattern_file.nb"
+     )
++    set(EXTRA_DEPENDS "${OUT_DIR}/py_stub_test.py")
+   else()
+     set(EXTRA "")
++    set(EXTRA_DEPENDS "")
+   endif()
+ 
+   if (CMAKE_CONFIGURATION_TYPES)
+@@ -112,7 +120,7 @@ foreach (NAME functions classes ndarray jax tensorflow stl enum typing make_iter
+     MODULE test_${NAME}_ext
+     OUTPUT ${PYI_PREFIX}test_${NAME}_ext.pyi
+     PYTHON_PATH $<TARGET_FILE_DIR:test_${NAME}_ext>
+-    DEPENDS test_${NAME}_ext
++    DEPENDS test_${NAME}_ext ${EXTRA_DEPENDS}
+     ${EXTRA})
+ endforeach()
+ 
+@@ -179,12 +187,6 @@ set(TEST_FILES
+ 
+ set (PY_STUB_TEST py_stub_test.py)
+ if (NOT (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_CURRENT_BINARY_DIR) OR MSVC)
+-  if (CMAKE_CONFIGURATION_TYPES)
+-    set(OUT_DIR ${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>)
+-  else()
+-    set(OUT_DIR ${CMAKE_CURRENT_BINARY_DIR})
+-  endif()
+-
+   foreach(TEST_FILE IN LISTS TEST_FILES)
+     set(IN_FILE ${CMAKE_CURRENT_SOURCE_DIR}/${TEST_FILE})
+     set(OUT_FILE ${OUT_DIR}/${TEST_FILE})
diff --git a/python-nanobind.changes b/python-nanobind.changes
index a6c0307..9a683b7 100644
--- a/python-nanobind.changes
+++ b/python-nanobind.changes
@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Wed Apr  9 14:51:23 UTC 2025 - Friedrich Haubensak <hsk17@mail.de>
+
+- add nanobind-2.6.1-test-build.patch to fix test on single
+  processor (boo #1239153)
+
+-------------------------------------------------------------------
 Fri Mar 18 18:32:19 UTC 2025 - Friedrich Haubensak <hsk17@mail.de>
 
 - update to release 2.6.1
diff --git a/python-nanobind.spec b/python-nanobind.spec
index 1d11258..70a1f32 100644
--- a/python-nanobind.spec
+++ b/python-nanobind.spec
@@ -26,6 +26,8 @@ URL:            https://github.com/wjakob/nanobind
 Source:         https://github.com/wjakob/nanobind/archive/refs/tags/v%{version}.tar.gz#/nanobind-%{version}.tar.gz
 # PATCH-FEATURE-OPENSUSE nanobind-installationpath.patch
 Patch1:         nanobind-installationpath.patch
+# PATCH-FIX_UPSTREAM nanobind-2.6.1-test-build.patch
+Patch2:         nanobind-2.6.1-test-build.patch
 BuildRequires:  cmake
 BuildRequires:  %{python_module base}
 BuildRequires:  python-rpm-macros