diff --git a/test/impl/random.cpp b/test/impl/random.cpp
index 35d81d6..4b9f328 100644
--- a/test/impl/random.cpp
+++ b/test/impl/random.cpp
@@ -1,12 +1,12 @@
 #include <obfs/random.hpp>
 #include <catch2/catch.hpp>
 
-using uint64_t = unsigned long long;
+using ull = unsigned long long;
 
 // https://en.wikipedia.org/wiki/Xorshift
-uint64_t xorshift128plus(uint64_t state[2]) {
-	uint64_t t = state[0];
-	uint64_t const s = state[1];
+ull xorshift128plus(ull state[2]) {
+	ull t = state[0];
+	ull const s = state[1];
 	state[0] = s;
 	t ^= t << 23;		// a
 	t ^= t >> 17;		// b
@@ -17,7 +17,7 @@ uint64_t xorshift128plus(uint64_t state[2]) {
 
 TEST_CASE("Random case", "[obfs::Xorshift+]") {
     constexpr size_t val = MAKE_RAND_VAL(100);
-    uint64_t state[2] = { val, val << 1 };
+    ull state[2] = { val, val << 1 };
 
     REQUIRE(obfs::Xorshiftplus<val, 1>::value == xorshift128plus(state));
     REQUIRE(obfs::Xorshiftplus<val, 2>::value == xorshift128plus(state));