diff --git a/lib/libc/tests/stdlib/getenv_r_test.c b/lib/libc/tests/stdlib/getenv_r_test.c
--- a/lib/libc/tests/stdlib/getenv_r_test.c
+++ b/lib/libc/tests/stdlib/getenv_r_test.c
@@ -55,7 +55,7 @@
 
 	ATF_REQUIRE_EQ(0, setenv("ATF_TC_IDENT", ident, 1));
 	errno = 0;
-	ATF_REQUIRE_EQ(-1, getenv_r(NULL, buf, strlen(ident)));
+	ATF_REQUIRE_EQ(-1, getenv_r("ATF_TC_IDENT", buf, strlen(ident)));
 	ATF_REQUIRE_EQ(ERANGE, errno);
 }