diff --git a/platforms/posix/src/px4/windows/tests/test_windows_shim_headers.cpp b/platforms/posix/src/px4/windows/tests/test_windows_shim_headers.cpp
index 06e91c30c7..5b12dc22fa 100644
--- a/platforms/posix/src/px4/windows/tests/test_windows_shim_headers.cpp
+++ b/platforms/posix/src/px4/windows/tests/test_windows_shim_headers.cpp
@@ -52,6 +52,17 @@
 #include <chrono>
 #include <thread>
 
+/* The shim header for usleep references three tunables that are normally
+ * defined in platforms/posix/src/px4/windows/runtime/init.cpp. This unit
+ * test binary intentionally does not link init.cpp (it would drag in the
+ * full runtime), so we provide local definitions matching the documented
+ * defaults. Keep them in sync with init.cpp. */
+extern "C" {
+	long g_usleep_pure_spin_us = 5000;
+	long g_usleep_spin_tail_us = 1000;
+	long g_usleep_adaptive_min_tail_us = 700;
+}
+
 /* Pull headers via the shim include path so the inline functions under
  * test are the same definitions PX4 sources see. */
 #include <libgen.h>