diff --git a/test/std-test.cc b/test/std-test.cc
index 4279fec1..41183dbf 100644
--- a/test/std-test.cc
+++ b/test/std-test.cc
@@ -238,9 +238,8 @@ TEST(std_test, format_const_bit_reference) {
 }
 
 TEST(std_test, format_bitset) {
-  const std::bitset<6> bs(42);
+  auto bs = std::bitset<6>(42);
   EXPECT_EQ(fmt::format("{}", bs), "101010");
-  EXPECT_EQ(fmt::format("{:.4}", bs), "101010");
   EXPECT_EQ(fmt::format("{:0>8}", bs), "00101010");
   EXPECT_EQ(fmt::format("{:-^12}", bs), "---101010---");
 }