diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index e9a3080..88f5851 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -968,7 +968,7 @@
   VERIFY_SYSCONF_POSIX_VERSION(_SC_CPUTIME);
   VERIFY_SYSCONF_POSITIVE(_SC_EXPR_NEST_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_LINE_MAX);
-  VERIFY_SYSCONF_POSITIVE(_SC_NGROUPS_MAX);
+  VerifySysconf(_SC_NGROUPS_MAX, "_SC_NGROUPS_MAX", [](long v){return v >= 0 && v <= NGROUPS_MAX;});
   VERIFY_SYSCONF_POSITIVE(_SC_OPEN_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_PASS_MAX);
   VERIFY_SYSCONF_POSIX_VERSION(_SC_2_C_BIND);