diff --git a/tests/dirent_test.cpp b/tests/dirent_test.cpp
index 4d21246..cde2d11 100644
--- a/tests/dirent_test.cpp
+++ b/tests/dirent_test.cpp
@@ -33,11 +33,11 @@
 
 static void CheckProcSelf(std::set<std::string>& names) {
   // We have a good idea of what should be in /proc/self.
-  ASSERT_TRUE(names.find(".") != names.end());
-  ASSERT_TRUE(names.find("..") != names.end());
-  ASSERT_TRUE(names.find("cmdline") != names.end());
-  ASSERT_TRUE(names.find("fd") != names.end());
-  ASSERT_TRUE(names.find("stat") != names.end());
+  ASSERT_TRUE(names.contains("."));
+  ASSERT_TRUE(names.contains(".."));
+  ASSERT_TRUE(names.contains("cmdline"));
+  ASSERT_TRUE(names.contains("fd"));
+  ASSERT_TRUE(names.contains("stat"));
 }
 
 template <typename DirEntT>
diff --git a/tests/ifaddrs_test.cpp b/tests/ifaddrs_test.cpp
index b3ab94d..da64770 100644
--- a/tests/ifaddrs_test.cpp
+++ b/tests/ifaddrs_test.cpp
@@ -137,7 +137,7 @@
   sockaddr_in* sock = reinterpret_cast<sockaddr_in*>(&ifr.ifr_addr);
   in_addr_t addr = sock->sin_addr.s_addr;
 
-  EXPECT_TRUE(addrs.find(addr) != addrs.end()) << if_name << ' ' << std::hex << ntohl(addr);
+  EXPECT_TRUE(addrs.contains(addr)) << if_name << ' ' << std::hex << ntohl(addr);
 }
 
 TEST(ifaddrs, getifaddrs_INET) {
diff --git a/tests/link_test.cpp b/tests/link_test.cpp
index 127a3d9..ae3a1cd 100644
--- a/tests/link_test.cpp
+++ b/tests/link_test.cpp
@@ -195,7 +195,7 @@
     }
     void AddModule(dl_phdr_info* info, size_t s) {
       ASSERT_EQ(sizeof(dl_phdr_info), s);
-      ASSERT_TRUE(dl_iter_mods.find(info->dlpi_addr) == dl_iter_mods.end());
+      ASSERT_FALSE(dl_iter_mods.contains(info->dlpi_addr));
       ASSERT_TRUE(info->dlpi_name != nullptr);
       dl_iter_mods[info->dlpi_addr] = {
         .name = info->dlpi_name,
diff --git a/tests/stack_protector_test.cpp b/tests/stack_protector_test.cpp
index aea791c..5817a27 100644
--- a/tests/stack_protector_test.cpp
+++ b/tests/stack_protector_test.cpp
@@ -48,7 +48,7 @@
     printf("[thread %d] TLS stack guard = %p\n", tid, guard);
 
     // Duplicate tid. gettid(2) bug? Seeing this would be very upsetting.
-    ASSERT_TRUE(tids.find(tid) == tids.end());
+    ASSERT_FALSE(tids.contains(tid));
 
     // Uninitialized guard. Our bug. Note this is potentially flaky; we _could_
     // get four random zero bytes, but it should be vanishingly unlikely.