diff --git a/libc/test/IntegrationTest/test.h b/libc/test/IntegrationTest/test.h
index 1e5ad1cfef0d7..c015bb44586ff 100644
--- a/libc/test/IntegrationTest/test.h
+++ b/libc/test/IntegrationTest/test.h
@@ -45,10 +45,17 @@
       LIBC_NAMESPACE::quick_exit(127);                                         \
   }
 
+////////////////////////////////////////////////////////////////////////////////
+// Boolean checks are handled as comparison to the true / false values.
+
 #define EXPECT_TRUE(val) __CHECK_TRUE(__FILE__, __LINE__, val, false)
 #define ASSERT_TRUE(val) __CHECK_TRUE(__FILE__, __LINE__, val, true)
 #define EXPECT_FALSE(val) __CHECK_FALSE(__FILE__, __LINE__, val, false)
 #define ASSERT_FALSE(val) __CHECK_FALSE(__FILE__, __LINE__, val, true)
+
+////////////////////////////////////////////////////////////////////////////////
+// Binary equality / inequality.
+
 #define EXPECT_EQ(val1, val2)                                                  \
   __CHECK_EQ(__FILE__, __LINE__, (val1), (val2), false)
 #define ASSERT_EQ(val1, val2)                                                  \
@@ -58,6 +65,13 @@
 #define ASSERT_NE(val1, val2)                                                  \
   __CHECK_NE(__FILE__, __LINE__, (val1), (val2), true)
 
+////////////////////////////////////////////////////////////////////////////////
+// Errno checks.
+
+#define ASSERT_ERRNO_EQ(VAL) ASSERT_EQ(VAL, static_cast<int>(libc_errno))
+#define ASSERT_ERRNO_SUCCESS() ASSERT_EQ(0, static_cast<int>(libc_errno))
+#define ASSERT_ERRNO_FAILURE() ASSERT_NE(0, static_cast<int>(libc_errno))
+
 // Integration tests are compiled with -ffreestanding which stops treating
 // the main function as a non-overloadable special function. Hence, we use a
 // convenience macro which declares it 'extern "C"'.
diff --git a/libc/test/UnitTest/LibcTest.h b/libc/test/UnitTest/LibcTest.h
index 68fd5f28f3e0b..1a90d10d7ec01 100644
--- a/libc/test/UnitTest/LibcTest.h
+++ b/libc/test/UnitTest/LibcTest.h
@@ -443,6 +443,13 @@ CString libc_make_test_file_path_func(const char *file_name);
 #define EXPECT_STRNE(LHS, RHS) LIBC_TEST_STR_(testStrNe, LHS, RHS, )
 #define ASSERT_STRNE(LHS, RHS) LIBC_TEST_STR_(testStrNe, LHS, RHS, return)
 
+////////////////////////////////////////////////////////////////////////////////
+// Errno checks.
+
+#define ASSERT_ERRNO_EQ(VAL) ASSERT_EQ(VAL, static_cast<int>(libc_errno))
+#define ASSERT_ERRNO_SUCCESS() ASSERT_EQ(0, static_cast<int>(libc_errno))
+#define ASSERT_ERRNO_FAILURE() ASSERT_NE(0, static_cast<int>(libc_errno))
+
 ////////////////////////////////////////////////////////////////////////////////
 // Subprocess checks.
 
diff --git a/libc/test/integration/src/pthread/pthread_create_test.cpp b/libc/test/integration/src/pthread/pthread_create_test.cpp
index 6a9b44cc1422c..5da91c6ec9a7d 100644
--- a/libc/test/integration/src/pthread/pthread_create_test.cpp
+++ b/libc/test/integration/src/pthread/pthread_create_test.cpp
@@ -47,7 +47,7 @@ static void *successThread(void *Arg) {
   pthread_t th = LIBC_NAMESPACE::pthread_self();
   auto *thread = reinterpret_cast<LIBC_NAMESPACE::Thread *>(&th);
 
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_TRUE(thread);
   ASSERT_TRUE(thread->attrib);
 
@@ -62,22 +62,22 @@ static void *successThread(void *Arg) {
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_getstack(expec_attrs, &expec_stack,
                                                   &expec_stacksize),
             0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(
       LIBC_NAMESPACE::pthread_attr_getstacksize(expec_attrs, &expec_stacksize2),
       0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(
       LIBC_NAMESPACE::pthread_attr_getguardsize(expec_attrs, &expec_guardsize),
       0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(
       LIBC_NAMESPACE::pthread_attr_getdetachstate(expec_attrs, &expec_detached),
       0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(expec_stacksize, expec_stacksize2);
 
@@ -125,7 +125,7 @@ static void *successThread(void *Arg) {
   // permissions. Maybe we can read from /proc/{self}/map?
 
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_destroy(expec_attrs), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   // Arg is malloced, so free.
   delete th_arg;
@@ -140,13 +140,13 @@ static void run_success_config(int detachstate, size_t guardsize,
   pthread_attr_t *attr = &(th_arg->attrs);
 
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_init(attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_setdetachstate(attr, detachstate), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_setguardsize(attr, guardsize), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   void *Stack = nullptr;
   if (customstack) {
@@ -154,20 +154,20 @@ static void run_success_config(int detachstate, size_t guardsize,
                                  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
     ASSERT_NE(Stack, MAP_FAILED);
     ASSERT_NE(Stack, static_cast<void *>(nullptr));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_setstack(attr, Stack, stacksize), 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
   } else {
     ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_setstacksize(attr, stacksize), 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
   }
 
   void *expec_ret = nullptr;
   if (detachstate == PTHREAD_CREATE_JOINABLE) {
     ASSERT_EQ(LIBC_NAMESPACE::getrandom(&expec_ret, sizeof(expec_ret), 0),
               static_cast<ssize_t>(sizeof(expec_ret)));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
   }
 
   th_arg->ret = expec_ret;
@@ -178,17 +178,17 @@ static void run_success_config(int detachstate, size_t guardsize,
   ASSERT_EQ(LIBC_NAMESPACE::pthread_create(&tid, attr, successThread,
                                            reinterpret_cast<void *>(th_arg)),
             0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   if (detachstate == PTHREAD_CREATE_JOINABLE) {
     void *th_ret;
     ASSERT_EQ(LIBC_NAMESPACE::pthread_join(tid, &th_ret), 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     ASSERT_EQ(th_ret, expec_ret);
 
     if (customstack) {
       ASSERT_EQ(LIBC_NAMESPACE::munmap(Stack, stacksize), 0);
-      ASSERT_EQ(libc_errno, 0);
+      ASSERT_ERRNO_SUCCESS();
     }
   } else {
     ASSERT_FALSE(customstack);
@@ -260,23 +260,23 @@ static void create_and_check_failure_thread(pthread_attr_t *attr) {
   // was just really larger we failed mmap.
   ASSERT_TRUE(result == EINVAL || result == EAGAIN);
   // pthread_create should NOT set errno on error
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_destroy(attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 }
 
 static void run_failure_config(size_t guardsize, size_t stacksize) {
   pthread_attr_t attr;
   guardsize &= -EXEC_PAGESIZE;
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_init(&attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_setguardsize(&attr, guardsize), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_setstacksize(&attr, stacksize), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   create_and_check_failure_thread(&attr);
 }
@@ -301,32 +301,32 @@ static void run_failure_tests() {
 
   // Stacksize too small.
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_init(&attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   attr.__stacksize = PTHREAD_STACK_MIN - 16;
   create_and_check_failure_thread(&attr);
 
   // Stack misaligned.
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_init(&attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   attr.__stack = reinterpret_cast<void *>(1);
   create_and_check_failure_thread(&attr);
 
   // Stack + stacksize misaligned.
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_init(&attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   attr.__stacksize = PTHREAD_STACK_MIN + 1;
   attr.__stack = reinterpret_cast<void *>(16);
   create_and_check_failure_thread(&attr);
 
   // Guardsize misaligned.
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_init(&attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   attr.__guardsize = EXEC_PAGESIZE / 2;
   create_and_check_failure_thread(&attr);
 
   // Detachstate is unknown.
   ASSERT_EQ(LIBC_NAMESPACE::pthread_attr_init(&attr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   attr.__detachstate = -1;
   create_and_check_failure_thread(&attr);
 }
diff --git a/libc/test/integration/src/pthread/pthread_join_test.cpp b/libc/test/integration/src/pthread/pthread_join_test.cpp
index f4126357a0579..da1a968aa47d3 100644
--- a/libc/test/integration/src/pthread/pthread_join_test.cpp
+++ b/libc/test/integration/src/pthread/pthread_join_test.cpp
@@ -19,9 +19,9 @@ static void nullJoinTest() {
   pthread_t Tid;
   ASSERT_EQ(LIBC_NAMESPACE::pthread_create(&Tid, nullptr, simpleFunc, nullptr),
             0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::pthread_join(Tid, nullptr), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 }
 
 TEST_MAIN() {
diff --git a/libc/test/integration/src/unistd/getcwd_test.cpp b/libc/test/integration/src/unistd/getcwd_test.cpp
index 3d8f5821a69ef..87687d09b9e7a 100644
--- a/libc/test/integration/src/unistd/getcwd_test.cpp
+++ b/libc/test/integration/src/unistd/getcwd_test.cpp
@@ -30,7 +30,7 @@ TEST_MAIN(int argc, char **argv, char **envp) {
   // Bad size
   cwd = LIBC_NAMESPACE::getcwd(buffer, 0);
   ASSERT_TRUE(cwd == nullptr);
-  ASSERT_EQ(libc_errno, EINVAL);
+  ASSERT_ERRNO_EQ(EINVAL);
   libc_errno = 0;
 
   // Insufficient size
diff --git a/libc/test/src/dirent/dirent_test.cpp b/libc/test/src/dirent/dirent_test.cpp
index ff1a30a2639fe..e2e0399673be6 100644
--- a/libc/test/src/dirent/dirent_test.cpp
+++ b/libc/test/src/dirent/dirent_test.cpp
@@ -44,7 +44,7 @@ TEST(LlvmLibcDirentTest, SimpleOpenAndRead) {
   }
 
   // Verify that we don't break out of the above loop in error.
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_TRUE(file1 != nullptr);
   ASSERT_TRUE(file2 != nullptr);
@@ -58,7 +58,7 @@ TEST(LlvmLibcDirentTest, OpenNonExistentDir) {
   libc_errno = 0;
   ::DIR *dir = LIBC_NAMESPACE::opendir("___xyz123__.non_existent__");
   ASSERT_TRUE(dir == nullptr);
-  ASSERT_EQ(libc_errno, ENOENT);
+  ASSERT_ERRNO_EQ(ENOENT);
   libc_errno = 0;
 }
 
@@ -66,6 +66,6 @@ TEST(LlvmLibcDirentTest, OpenFile) {
   libc_errno = 0;
   ::DIR *dir = LIBC_NAMESPACE::opendir("testdata/file1.txt");
   ASSERT_TRUE(dir == nullptr);
-  ASSERT_EQ(libc_errno, ENOTDIR);
+  ASSERT_ERRNO_EQ(ENOTDIR);
   libc_errno = 0;
 }
diff --git a/libc/test/src/fcntl/creat_test.cpp b/libc/test/src/fcntl/creat_test.cpp
index ef30d8862c45f..4c9d2cbc33f47 100644
--- a/libc/test/src/fcntl/creat_test.cpp
+++ b/libc/test/src/fcntl/creat_test.cpp
@@ -19,12 +19,12 @@ TEST(LlvmLibcCreatTest, CreatAndOpen) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/creat.test";
   int fd = LIBC_NAMESPACE::creat(TEST_FILE, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
diff --git a/libc/test/src/fcntl/openat_test.cpp b/libc/test/src/fcntl/openat_test.cpp
index b95f3f2127201..9dafd125224a4 100644
--- a/libc/test/src/fcntl/openat_test.cpp
+++ b/libc/test/src/fcntl/openat_test.cpp
@@ -21,13 +21,13 @@ TEST(LlvmLibcUniStd, OpenAndReadTest) {
   constexpr const char *TEST_DIR = "testdata";
   constexpr const char *TEST_FILE = "openat.test";
   int dir_fd = LIBC_NAMESPACE::open(TEST_DIR, O_DIRECTORY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(dir_fd, 0);
   constexpr const char TEST_MSG[] = "openat test";
   constexpr int TEST_MSG_SIZE = sizeof(TEST_MSG) - 1;
 
   int read_fd = LIBC_NAMESPACE::openat(dir_fd, TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(read_fd, 0);
   char read_buf[TEST_MSG_SIZE];
   ASSERT_THAT(LIBC_NAMESPACE::read(read_fd, read_buf, TEST_MSG_SIZE),
diff --git a/libc/test/src/sched/get_priority_test.cpp b/libc/test/src/sched/get_priority_test.cpp
index 3a79a67802cf3..4ff7890c4f404 100644
--- a/libc/test/src/sched/get_priority_test.cpp
+++ b/libc/test/src/sched/get_priority_test.cpp
@@ -20,40 +20,40 @@ TEST(LlvmLibcSchedGetPriorityTest, HandleBadPolicyTest) {
     int policy = -1;
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_EQ(max_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_EQ(min_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
   }
 
   {
     int policy = 30;
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_EQ(max_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_EQ(min_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
   }
 
   {
     int policy = 80;
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_EQ(max_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_EQ(min_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
   }
 
   {
     int policy = 110;
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_EQ(max_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_EQ(min_priority, -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
   }
 }
 
@@ -68,10 +68,10 @@ TEST(LlvmLibcSchedGetPriorityTest, SmokeTest) {
     int policy = SCHED_OTHER;
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_GE(max_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_GE(min_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     ASSERT_LE(max_priority, 99);
     ASSERT_GE(min_priority, 0);
@@ -82,10 +82,10 @@ TEST(LlvmLibcSchedGetPriorityTest, SmokeTest) {
     int policy = SCHED_FIFO;
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_GE(max_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_GE(min_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     ASSERT_LE(max_priority, 99);
     ASSERT_GE(min_priority, 0);
@@ -96,10 +96,10 @@ TEST(LlvmLibcSchedGetPriorityTest, SmokeTest) {
     int policy = SCHED_RR;
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_GE(max_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_GE(min_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     ASSERT_LE(max_priority, 99);
     ASSERT_GE(min_priority, 0);
diff --git a/libc/test/src/sched/param_and_scheduler_test.cpp b/libc/test/src/sched/param_and_scheduler_test.cpp
index 8c6485f078971..7fcb667a31a9d 100644
--- a/libc/test/src/sched/param_and_scheduler_test.cpp
+++ b/libc/test/src/sched/param_and_scheduler_test.cpp
@@ -41,35 +41,35 @@ class SchedTest : public LIBC_NAMESPACE::testing::Test {
 
     int init_policy = LIBC_NAMESPACE::sched_getscheduler(0);
     ASSERT_GE(init_policy, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     int max_priority = LIBC_NAMESPACE::sched_get_priority_max(policy);
     ASSERT_GE(max_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_GE(min_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     struct sched_param param = {min_priority};
 
     // Negative pid
     ASSERT_EQ(LIBC_NAMESPACE::sched_setscheduler(-1, policy, &param), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
 
     ASSERT_EQ(LIBC_NAMESPACE::sched_getscheduler(-1), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
 
     // Invalid Policy
     ASSERT_EQ(LIBC_NAMESPACE::sched_setscheduler(0, policy | 128, &param), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
 
     // Out of bounds priority
     param.sched_priority = min_priority - 1;
     ASSERT_EQ(LIBC_NAMESPACE::sched_setscheduler(0, policy, &param), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
 
     param.sched_priority = max_priority + 1;
@@ -90,33 +90,33 @@ class SchedTest : public LIBC_NAMESPACE::testing::Test {
 
     ASSERT_EQ(LIBC_NAMESPACE::sched_getscheduler(0),
               can_set ? policy : init_policy);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     // Out of bounds priority
     param.sched_priority = -1;
     ASSERT_EQ(LIBC_NAMESPACE::sched_setparam(0, &param), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
 
     param.sched_priority = max_priority + 1;
     ASSERT_EQ(LIBC_NAMESPACE::sched_setparam(0, &param), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
 
     for (int priority = min_priority; priority <= max_priority; ++priority) {
       ASSERT_EQ(LIBC_NAMESPACE::sched_getparam(0, &param), 0);
-      ASSERT_EQ(libc_errno, 0);
+      ASSERT_ERRNO_SUCCESS();
       int init_priority = param.sched_priority;
 
       param.sched_priority = priority;
 
       // Negative pid
       ASSERT_EQ(LIBC_NAMESPACE::sched_setparam(-1, &param), -1);
-      ASSERT_EQ(libc_errno, EINVAL);
+      ASSERT_ERRNO_EQ(EINVAL);
       libc_errno = 0;
 
       ASSERT_EQ(LIBC_NAMESPACE::sched_getparam(-1, &param), -1);
-      ASSERT_EQ(libc_errno, EINVAL);
+      ASSERT_ERRNO_EQ(EINVAL);
       libc_errno = 0;
 
       // Success / missing permissions
@@ -126,14 +126,14 @@ class SchedTest : public LIBC_NAMESPACE::testing::Test {
       libc_errno = 0;
 
       ASSERT_EQ(LIBC_NAMESPACE::sched_getparam(0, &param), 0);
-      ASSERT_EQ(libc_errno, 0);
+      ASSERT_ERRNO_SUCCESS();
 
       ASSERT_EQ(param.sched_priority, can_set ? priority : init_priority);
     }
 
     // Null test
     ASSERT_EQ(LIBC_NAMESPACE::sched_setscheduler(0, policy, nullptr), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
   }
 };
@@ -155,10 +155,10 @@ TEST(LlvmLibcSchedParamAndSchedulerTest, NullParamTest) {
   libc_errno = 0;
 
   ASSERT_EQ(LIBC_NAMESPACE::sched_setparam(0, nullptr), -1);
-  ASSERT_EQ(libc_errno, EINVAL);
+  ASSERT_ERRNO_EQ(EINVAL);
   libc_errno = 0;
 
   ASSERT_EQ(LIBC_NAMESPACE::sched_getparam(0, nullptr), -1);
-  ASSERT_EQ(libc_errno, EINVAL);
+  ASSERT_ERRNO_EQ(EINVAL);
   libc_errno = 0;
 }
diff --git a/libc/test/src/sched/sched_rr_get_interval_test.cpp b/libc/test/src/sched/sched_rr_get_interval_test.cpp
index 1001000795041..5e024f07ced12 100644
--- a/libc/test/src/sched/sched_rr_get_interval_test.cpp
+++ b/libc/test/src/sched/sched_rr_get_interval_test.cpp
@@ -21,11 +21,11 @@ TEST(LlvmLibcSchedRRGetIntervalTest, SmokeTest) {
   auto SetSched = [&](int policy) {
     int min_priority = LIBC_NAMESPACE::sched_get_priority_min(policy);
     ASSERT_GE(min_priority, 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     struct sched_param param;
     param.sched_priority = min_priority;
     ASSERT_EQ(LIBC_NAMESPACE::sched_setscheduler(0, policy, &param), 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
   };
 
   auto TimespecToNs = [](struct timespec t) {
@@ -41,13 +41,13 @@ TEST(LlvmLibcSchedRRGetIntervalTest, SmokeTest) {
 
   int cur_policy = LIBC_NAMESPACE::sched_getscheduler(0);
   ASSERT_GE(cur_policy, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   // We can actually run meaningful tests.
   if (cur_policy == SCHED_RR) {
     // Success
     ASSERT_EQ(LIBC_NAMESPACE::sched_rr_get_interval(0, &ts), 0);
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     // Check that numbers make sense (liberal bound of 10ns - 30sec)
     constexpr uint64_t tenNs = 10UL;
@@ -57,19 +57,19 @@ TEST(LlvmLibcSchedRRGetIntervalTest, SmokeTest) {
 
     // Null timespec
     ASSERT_EQ(LIBC_NAMESPACE::sched_rr_get_interval(0, nullptr), -1);
-    ASSERT_EQ(libc_errno, EFAULT);
+    ASSERT_ERRNO_EQ(EFAULT);
     libc_errno = 0;
 
     // Negative pid
     ASSERT_EQ(LIBC_NAMESPACE::sched_rr_get_interval(-1, &ts), -1);
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
     libc_errno = 0;
   }
 
   // Negative tests don't have SCHED_RR set
   SetSched(SCHED_OTHER);
   ASSERT_EQ(LIBC_NAMESPACE::sched_rr_get_interval(0, &ts), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   libc_errno = 0;
 
   // TODO: Missing unkown pid -> ESRCH. This is read only so safe to try a few
diff --git a/libc/test/src/sched/yield_test.cpp b/libc/test/src/sched/yield_test.cpp
index 45b7a7d2d81e4..5e4e07bc199b6 100644
--- a/libc/test/src/sched/yield_test.cpp
+++ b/libc/test/src/sched/yield_test.cpp
@@ -15,5 +15,5 @@ TEST(LlvmLibcSchedYieldTest, SmokeTest) {
   // sched_yield() always succeeds, just do a basic test that errno/ret are
   // properly 0.
   ASSERT_EQ(LIBC_NAMESPACE::sched_yield(), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 }
diff --git a/libc/test/src/stdio/fgets_test.cpp b/libc/test/src/stdio/fgets_test.cpp
index 9f9841c901f4e..aab8bae3d97e9 100644
--- a/libc/test/src/stdio/fgets_test.cpp
+++ b/libc/test/src/stdio/fgets_test.cpp
@@ -48,7 +48,7 @@ TEST(LlvmLibcFgetsTest, WriteAndReadCharacters) {
   output = LIBC_NAMESPACE::fgets(buff, 1, file);
   ASSERT_TRUE(output == buff);
   ASSERT_EQ(buff[0], '\0');
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   // If we request less than 1 byte, it should do nothing and return nullptr.
   // This is also implementation defined.
@@ -76,13 +76,13 @@ TEST(LlvmLibcFgetsTest, WriteAndReadCharacters) {
   // fails to read anything.
   ASSERT_NE(LIBC_NAMESPACE::feof(file), 0);
   ASSERT_EQ(LIBC_NAMESPACE::ferror(file), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   // Reading more should be an EOF, but not an error.
   output = LIBC_NAMESPACE::fgets(buff, 8, file);
   ASSERT_TRUE(output == nullptr);
   ASSERT_NE(LIBC_NAMESPACE::feof(file), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));
 }
diff --git a/libc/test/src/stdio/fileop_test.cpp b/libc/test/src/stdio/fileop_test.cpp
index d5478e58eecbf..d620aa076ef0d 100644
--- a/libc/test/src/stdio/fileop_test.cpp
+++ b/libc/test/src/stdio/fileop_test.cpp
@@ -121,16 +121,16 @@ TEST(LlvmLibcFILETest, SimpleFileOperations) {
 
   // libc_errno = 0;
   // ASSERT_NE(LIBC_NAMESPACE::fseek(file, 0, SEEK_SET), 0);
-  // EXPECT_NE(libc_errno, 0);
+  // ASSERT_ERRNO_FAILURE();
 
   // libc_errno = 0;
   // ASSERT_NE(LIBC_NAMESPACE::fclose(file), 0);
-  // EXPECT_NE(libc_errno, 0);
+  // ASSERT_ERRNO_FAILURE();
 
   // libc_errno = 0;
   // ASSERT_EQ(LIBC_NAMESPACE::fopen("INVALID FILE NAME", "r"),
   //           static_cast<FILE *>(nullptr));
-  // EXPECT_NE(libc_errno, 0);
+  // ASSERT_ERRNO_FAILURE();
 }
 
 TEST(LlvmLibcFILETest, FFlush) {
diff --git a/libc/test/src/stdio/fopencookie_test.cpp b/libc/test/src/stdio/fopencookie_test.cpp
index 6f3c2910cfd82..2edfc7e210d7e 100644
--- a/libc/test/src/stdio/fopencookie_test.cpp
+++ b/libc/test/src/stdio/fopencookie_test.cpp
@@ -114,7 +114,7 @@ TEST(LlvmLibcFOpenCookie, ReadOnlyCookieTest) {
   // Should be an error to write.
   ASSERT_EQ(size_t(0), LIBC_NAMESPACE::fwrite(CONTENT, 1, sizeof(CONTENT), f));
   ASSERT_NE(LIBC_NAMESPACE::ferror(f), 0);
-  ASSERT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
 
   LIBC_NAMESPACE::clearerr(f);
@@ -148,7 +148,7 @@ TEST(LlvmLibcFOpenCookie, WriteOnlyCookieTest) {
   ASSERT_EQ(size_t(0),
             LIBC_NAMESPACE::fread(read_data, 1, sizeof(WRITE_DATA), f));
   ASSERT_NE(LIBC_NAMESPACE::ferror(f), 0);
-  ASSERT_EQ(libc_errno, EBADF);
+  ASSERT_ERRNO_EQ(EBADF);
   libc_errno = 0;
 
   LIBC_NAMESPACE::clearerr(f);
@@ -177,7 +177,7 @@ TEST(LlvmLibcFOpenCookie, AppendOnlyCookieTest) {
   // This is not a readable file.
   ASSERT_EQ(LIBC_NAMESPACE::fread(read_data, 1, READ_SIZE, f), size_t(0));
   ASSERT_NE(LIBC_NAMESPACE::ferror(f), 0);
-  EXPECT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
 
   LIBC_NAMESPACE::clearerr(f);
diff --git a/libc/test/src/stdio/remove_test.cpp b/libc/test/src/stdio/remove_test.cpp
index ce4a1352d1cc1..67bff906ef2a3 100644
--- a/libc/test/src/stdio/remove_test.cpp
+++ b/libc/test/src/stdio/remove_test.cpp
@@ -25,7 +25,7 @@ TEST(LlvmLibcRemoveTest, CreateAndRemoveFile) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/remove.test.file";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
diff --git a/libc/test/src/stdio/setvbuf_test.cpp b/libc/test/src/stdio/setvbuf_test.cpp
index 2faa01a15ec10..725694bb8ae1c 100644
--- a/libc/test/src/stdio/setvbuf_test.cpp
+++ b/libc/test/src/stdio/setvbuf_test.cpp
@@ -100,7 +100,7 @@ TEST(LlvmLibcSetbufTest, InvalidBufferMode) {
   char buf[BUFSIZ];
   ASSERT_NE(LIBC_NAMESPACE::setvbuf(f, buf, _IOFBF + _IOLBF + _IONBF, BUFSIZ),
             0);
-  ASSERT_EQ(libc_errno, EINVAL);
+  ASSERT_ERRNO_EQ(EINVAL);
 
   libc_errno = 0;
   ASSERT_EQ(0, LIBC_NAMESPACE::fclose(f));
diff --git a/libc/test/src/stdio/unlocked_fileop_test.cpp b/libc/test/src/stdio/unlocked_fileop_test.cpp
index cf51e8caa6a55..cf20701ca0e3b 100644
--- a/libc/test/src/stdio/unlocked_fileop_test.cpp
+++ b/libc/test/src/stdio/unlocked_fileop_test.cpp
@@ -36,7 +36,7 @@ TEST(LlvmLibcFILETest, UnlockedReadAndWrite) {
   ASSERT_EQ(size_t(0),
             LIBC_NAMESPACE::fread_unlocked(data, 1, sizeof(READ_SIZE), f));
   ASSERT_NE(LIBC_NAMESPACE::ferror_unlocked(f), 0);
-  ASSERT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
 
   LIBC_NAMESPACE::clearerr_unlocked(f);
@@ -57,7 +57,7 @@ TEST(LlvmLibcFILETest, UnlockedReadAndWrite) {
   ASSERT_EQ(size_t(0),
             LIBC_NAMESPACE::fwrite_unlocked(CONTENT, 1, sizeof(CONTENT), f));
   ASSERT_NE(LIBC_NAMESPACE::ferror_unlocked(f), 0);
-  ASSERT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
 
   LIBC_NAMESPACE::clearerr_unlocked(f);
diff --git a/libc/test/src/stdlib/StrtolTest.h b/libc/test/src/stdlib/StrtolTest.h
index 6aee049aa066a..8f1723b038612 100644
--- a/libc/test/src/stdlib/StrtolTest.h
+++ b/libc/test/src/stdlib/StrtolTest.h
@@ -37,7 +37,7 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *ten = "10";
     libc_errno = 0;
     ASSERT_EQ(func(ten, nullptr, -1), ReturnT(0));
-    ASSERT_EQ(libc_errno, EINVAL);
+    ASSERT_ERRNO_EQ(EINVAL);
   }
 
   void CleanBaseTenDecode(FunctionT func) {
@@ -47,23 +47,23 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *ten = "10";
     libc_errno = 0;
     ASSERT_EQ(func(ten, &str_end, 10), ReturnT(10));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - ten, ptrdiff_t(2));
 
     libc_errno = 0;
     ASSERT_EQ(func(ten, nullptr, 10), ReturnT(10));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
 
     const char *hundred = "100";
     libc_errno = 0;
     ASSERT_EQ(func(hundred, &str_end, 10), ReturnT(100));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - hundred, ptrdiff_t(3));
 
     const char *big_number = "1234567890";
     libc_errno = 0;
     ASSERT_EQ(func(big_number, &str_end, 10), ReturnT(1234567890));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - big_number, ptrdiff_t(10));
 
     // This number is larger than 2^32, meaning that if long is only 32 bits
@@ -72,24 +72,24 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     libc_errno = 0;
     if constexpr (sizeof(ReturnT) < 8) {
       ASSERT_EQ(func(bigger_number, &str_end, 10), T_MAX);
-      ASSERT_EQ(libc_errno, ERANGE);
+      ASSERT_ERRNO_EQ(ERANGE);
     } else {
       ASSERT_EQ(func(bigger_number, &str_end, 10), ReturnT(12345678900));
-      ASSERT_EQ(libc_errno, 0);
+      ASSERT_ERRNO_SUCCESS();
     }
     EXPECT_EQ(str_end - bigger_number, ptrdiff_t(11));
 
     const char *too_big_number = "123456789012345678901";
     libc_errno = 0;
     ASSERT_EQ(func(too_big_number, &str_end, 10), T_MAX);
-    ASSERT_EQ(libc_errno, ERANGE);
+    ASSERT_ERRNO_EQ(ERANGE);
     EXPECT_EQ(str_end - too_big_number, ptrdiff_t(21));
 
     const char *long_number_range_test =
         "10000000000000000000000000000000000000000000000000";
     libc_errno = 0;
     ASSERT_EQ(func(long_number_range_test, &str_end, 10), T_MAX);
-    ASSERT_EQ(libc_errno, ERANGE);
+    ASSERT_ERRNO_EQ(ERANGE);
     EXPECT_EQ(str_end - long_number_range_test, ptrdiff_t(50));
 
     // For most negative numbers, the unsigned functions treat it the same as
@@ -97,13 +97,13 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *negative = "-100";
     libc_errno = 0;
     ASSERT_EQ(func(negative, &str_end, 10), ReturnT(-100));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - negative, ptrdiff_t(4));
 
     const char *big_negative_number = "-1234567890";
     libc_errno = 0;
     ASSERT_EQ(func(big_negative_number, &str_end, 10), ReturnT(-1234567890));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - big_negative_number, ptrdiff_t(11));
 
     const char *too_big_negative_number = "-123456789012345678901";
@@ -117,7 +117,7 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     // Note that 0 is not on that list.
     ASSERT_EQ(func(too_big_negative_number, &str_end, 10),
               (is_signed_v<ReturnT> ? T_MIN : T_MAX));
-    ASSERT_EQ(libc_errno, ERANGE);
+    ASSERT_ERRNO_EQ(ERANGE);
     EXPECT_EQ(str_end - too_big_negative_number, ptrdiff_t(22));
   }
 
@@ -127,73 +127,73 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *spaces_before = "     10";
     libc_errno = 0;
     ASSERT_EQ(func(spaces_before, &str_end, 10), ReturnT(10));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - spaces_before, ptrdiff_t(7));
 
     const char *spaces_after = "10      ";
     libc_errno = 0;
     ASSERT_EQ(func(spaces_after, &str_end, 10), ReturnT(10));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - spaces_after, ptrdiff_t(2));
 
     const char *word_before = "word10";
     libc_errno = 0;
     ASSERT_EQ(func(word_before, &str_end, 10), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - word_before, ptrdiff_t(0));
 
     const char *word_after = "10word";
     libc_errno = 0;
     ASSERT_EQ(func(word_after, &str_end, 10), ReturnT(10));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - word_after, ptrdiff_t(2));
 
     const char *two_numbers = "10 999";
     libc_errno = 0;
     ASSERT_EQ(func(two_numbers, &str_end, 10), ReturnT(10));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - two_numbers, ptrdiff_t(2));
 
     const char *two_signs = "--10 999";
     libc_errno = 0;
     ASSERT_EQ(func(two_signs, &str_end, 10), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - two_signs, ptrdiff_t(0));
 
     const char *sign_before = "+2=4";
     libc_errno = 0;
     ASSERT_EQ(func(sign_before, &str_end, 10), ReturnT(2));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - sign_before, ptrdiff_t(2));
 
     const char *sign_after = "2+2=4";
     libc_errno = 0;
     ASSERT_EQ(func(sign_after, &str_end, 10), ReturnT(2));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - sign_after, ptrdiff_t(1));
 
     const char *tab_before = "\t10";
     libc_errno = 0;
     ASSERT_EQ(func(tab_before, &str_end, 10), ReturnT(10));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - tab_before, ptrdiff_t(3));
 
     const char *all_together = "\t  -12345and+67890";
     libc_errno = 0;
     ASSERT_EQ(func(all_together, &str_end, 10), ReturnT(-12345));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - all_together, ptrdiff_t(9));
 
     const char *just_spaces = "  ";
     libc_errno = 0;
     ASSERT_EQ(func(just_spaces, &str_end, 10), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - just_spaces, ptrdiff_t(0));
 
     const char *just_space_and_sign = " +";
     libc_errno = 0;
     ASSERT_EQ(func(just_space_and_sign, &str_end, 10), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - just_space_and_sign, ptrdiff_t(0));
   }
 
@@ -212,11 +212,11 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
           libc_errno = 0;
           ASSERT_EQ(func(small_string, nullptr, base),
                     static_cast<ReturnT>(first_digit));
-          ASSERT_EQ(libc_errno, 0);
+          ASSERT_ERRNO_SUCCESS();
         } else {
           libc_errno = 0;
           ASSERT_EQ(func(small_string, nullptr, base), ReturnT(0));
-          ASSERT_EQ(libc_errno, 0);
+          ASSERT_ERRNO_SUCCESS();
         }
       }
     }
@@ -231,16 +231,16 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
             ASSERT_EQ(
                 func(small_string, nullptr, base),
                 static_cast<ReturnT>(second_digit + (first_digit * base)));
-            ASSERT_EQ(libc_errno, 0);
+            ASSERT_ERRNO_SUCCESS();
           } else if (first_digit < base) {
             libc_errno = 0;
             ASSERT_EQ(func(small_string, nullptr, base),
                       static_cast<ReturnT>(first_digit));
-            ASSERT_EQ(libc_errno, 0);
+            ASSERT_ERRNO_SUCCESS();
           } else {
             libc_errno = 0;
             ASSERT_EQ(func(small_string, nullptr, base), ReturnT(0));
-            ASSERT_EQ(libc_errno, 0);
+            ASSERT_ERRNO_SUCCESS();
           }
         }
       }
@@ -261,13 +261,13 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
                         static_cast<ReturnT>(third_digit +
                                              (second_digit * base) +
                                              (first_digit * base * base)));
-              ASSERT_EQ(libc_errno, 0);
+              ASSERT_ERRNO_SUCCESS();
             } else if (first_digit < base && second_digit < base) {
               libc_errno = 0;
               ASSERT_EQ(
                   func(small_string, nullptr, base),
                   static_cast<ReturnT>(second_digit + (first_digit * base)));
-              ASSERT_EQ(libc_errno, 0);
+              ASSERT_ERRNO_SUCCESS();
             } else if (first_digit < base) {
               // if the base is 16 there is a special case for the prefix 0X.
               // The number is treated as a one digit hexadecimal.
@@ -276,22 +276,22 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
                   libc_errno = 0;
                   ASSERT_EQ(func(small_string, nullptr, base),
                             static_cast<ReturnT>(third_digit));
-                  ASSERT_EQ(libc_errno, 0);
+                  ASSERT_ERRNO_SUCCESS();
                 } else {
                   libc_errno = 0;
                   ASSERT_EQ(func(small_string, nullptr, base), ReturnT(0));
-                  ASSERT_EQ(libc_errno, 0);
+                  ASSERT_ERRNO_SUCCESS();
                 }
               } else {
                 libc_errno = 0;
                 ASSERT_EQ(func(small_string, nullptr, base),
                           static_cast<ReturnT>(first_digit));
-                ASSERT_EQ(libc_errno, 0);
+                ASSERT_ERRNO_SUCCESS();
               }
             } else {
               libc_errno = 0;
               ASSERT_EQ(func(small_string, nullptr, base), ReturnT(0));
-              ASSERT_EQ(libc_errno, 0);
+              ASSERT_ERRNO_SUCCESS();
             }
           }
         }
@@ -305,19 +305,19 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *no_prefix = "123abc";
     libc_errno = 0;
     ASSERT_EQ(func(no_prefix, &str_end, 16), ReturnT(0x123abc));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - no_prefix, ptrdiff_t(6));
 
     const char *yes_prefix = "0x456def";
     libc_errno = 0;
     ASSERT_EQ(func(yes_prefix, &str_end, 16), ReturnT(0x456def));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - yes_prefix, ptrdiff_t(8));
 
     const char *letter_after_prefix = "0xabc123";
     libc_errno = 0;
     ASSERT_EQ(func(letter_after_prefix, &str_end, 16), ReturnT(0xabc123));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - letter_after_prefix, ptrdiff_t(8));
 
     // These tests check what happens when the number passed is exactly the max
@@ -350,14 +350,14 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *max_31_bit_value = "0x7FFFFFFF";
     libc_errno = 0;
     ASSERT_EQ(func(max_31_bit_value, &str_end, 0), ReturnT(0x7FFFFFFF));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - max_31_bit_value, ptrdiff_t(10));
 
     const char *negative_max_31_bit_value = "-0x7FFFFFFF";
     libc_errno = 0;
     ASSERT_EQ(func(negative_max_31_bit_value, &str_end, 0),
               -ReturnT(0x7FFFFFFF));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - negative_max_31_bit_value, ptrdiff_t(11));
 
     // Max size for unsigned 64 bit numbers
@@ -391,7 +391,7 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     libc_errno = 0;
     ASSERT_EQ(func(max_63_bit_value, &str_end, 0),
               (sizeof(ReturnT) < 8 ? T_MAX : ReturnT(0x7FFFFFFFFFFFFFFF)));
-    ASSERT_EQ(libc_errno, sizeof(ReturnT) < 8 ? ERANGE : 0);
+    ASSERT_ERRNO_EQ(sizeof(ReturnT) < 8 ? ERANGE : 0);
     EXPECT_EQ(str_end - max_63_bit_value, ptrdiff_t(18));
 
     const char *negative_max_63_bit_value = "-0x7FFFFFFFFFFFFFFF";
@@ -399,7 +399,7 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     ASSERT_EQ(func(negative_max_63_bit_value, &str_end, 0),
               (sizeof(ReturnT) >= 8 ? -ReturnT(0x7FFFFFFFFFFFFFFF)
                                     : (is_signed_v<ReturnT> ? T_MIN : T_MAX)));
-    ASSERT_EQ(libc_errno, sizeof(ReturnT) < 8 ? ERANGE : 0);
+    ASSERT_ERRNO_EQ(sizeof(ReturnT) < 8 ? ERANGE : 0);
     EXPECT_EQ(str_end - negative_max_63_bit_value, ptrdiff_t(19));
   }
 
@@ -409,23 +409,23 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *just_prefix = "0x";
     libc_errno = 0;
     ASSERT_EQ(func(just_prefix, &str_end, 16), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - just_prefix, ptrdiff_t(1));
 
     libc_errno = 0;
     ASSERT_EQ(func(just_prefix, &str_end, 0), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - just_prefix, ptrdiff_t(1));
 
     const char *prefix_with_x_after = "0xx";
     libc_errno = 0;
     ASSERT_EQ(func(prefix_with_x_after, &str_end, 16), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - prefix_with_x_after, ptrdiff_t(1));
 
     libc_errno = 0;
     ASSERT_EQ(func(prefix_with_x_after, &str_end, 0), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - prefix_with_x_after, ptrdiff_t(1));
   }
 
@@ -435,43 +435,43 @@ struct StrtoTest : public LIBC_NAMESPACE::testing::Test {
     const char *base_ten = "12345";
     libc_errno = 0;
     ASSERT_EQ(func(base_ten, &str_end, 0), ReturnT(12345));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - base_ten, ptrdiff_t(5));
 
     const char *base_sixteen_no_prefix = "123abc";
     libc_errno = 0;
     ASSERT_EQ(func(base_sixteen_no_prefix, &str_end, 0), ReturnT(123));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - base_sixteen_no_prefix, ptrdiff_t(3));
 
     const char *base_sixteen_with_prefix = "0x456def";
     libc_errno = 0;
     ASSERT_EQ(func(base_sixteen_with_prefix, &str_end, 0), ReturnT(0x456def));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - base_sixteen_with_prefix, ptrdiff_t(8));
 
     const char *base_eight_with_prefix = "012345";
     libc_errno = 0;
     ASSERT_EQ(func(base_eight_with_prefix, &str_end, 0), ReturnT(012345));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - base_eight_with_prefix, ptrdiff_t(6));
 
     const char *just_zero = "0";
     libc_errno = 0;
     ASSERT_EQ(func(just_zero, &str_end, 0), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - just_zero, ptrdiff_t(1));
 
     const char *just_zero_x = "0x";
     libc_errno = 0;
     ASSERT_EQ(func(just_zero_x, &str_end, 0), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - just_zero_x, ptrdiff_t(1));
 
     const char *just_zero_eight = "08";
     libc_errno = 0;
     ASSERT_EQ(func(just_zero_eight, &str_end, 0), ReturnT(0));
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_EQ(str_end - just_zero_eight, ptrdiff_t(1));
   }
 };
diff --git a/libc/test/src/stdlib/strtof_test.cpp b/libc/test/src/stdlib/strtof_test.cpp
index f30c588c611b3..b43c32f902616 100644
--- a/libc/test/src/stdlib/strtof_test.cpp
+++ b/libc/test/src/stdlib/strtof_test.cpp
@@ -48,7 +48,7 @@ class LlvmLibcStrToFTest : public LIBC_NAMESPACE::testing::Test,
 
     EXPECT_EQ(str_end - inputString, expectedStrLen);
     EXPECT_FP_EQ(result, expected_fp.get_val());
-    EXPECT_EQ(libc_errno, expectedErrno);
+    ASSERT_ERRNO_EQ(expectedErrno);
   }
 };
 
diff --git a/libc/test/src/stdlib/strtold_test.cpp b/libc/test/src/stdlib/strtold_test.cpp
index b7942ab66460b..cbe0a47b9b710 100644
--- a/libc/test/src/stdlib/strtold_test.cpp
+++ b/libc/test/src/stdlib/strtold_test.cpp
@@ -90,7 +90,7 @@ class LlvmLibcStrToLDTest : public LIBC_NAMESPACE::testing::Test {
     EXPECT_EQ(actual_fp.is_neg(), expected_fp.is_neg());
     EXPECT_EQ(actual_fp.get_exponent(), expected_fp.get_exponent());
     EXPECT_EQ(actual_fp.get_mantissa(), expected_fp.get_mantissa());
-    EXPECT_EQ(libc_errno, expected_errno);
+    ASSERT_ERRNO_EQ(expected_errno);
   }
 };
 
diff --git a/libc/test/src/string/strdup_test.cpp b/libc/test/src/string/strdup_test.cpp
index b1d4df31603c4..caf8c2e61c0e2 100644
--- a/libc/test/src/string/strdup_test.cpp
+++ b/libc/test/src/string/strdup_test.cpp
@@ -17,7 +17,7 @@ TEST(LlvmLibcStrDupTest, EmptyString) {
 
   libc_errno = 0;
   char *result = LIBC_NAMESPACE::strdup(empty);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_NE(result, static_cast<char *>(nullptr));
   ASSERT_NE(empty, const_cast<const char *>(result));
@@ -30,7 +30,7 @@ TEST(LlvmLibcStrDupTest, AnyString) {
 
   libc_errno = 0;
   char *result = LIBC_NAMESPACE::strdup(abc);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_NE(result, static_cast<char *>(nullptr));
   ASSERT_NE(abc, const_cast<const char *>(result));
@@ -41,7 +41,7 @@ TEST(LlvmLibcStrDupTest, AnyString) {
 TEST(LlvmLibcStrDupTest, NullPtr) {
   libc_errno = 0;
   char *result = LIBC_NAMESPACE::strdup(nullptr);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_EQ(result, static_cast<char *>(nullptr));
 }
diff --git a/libc/test/src/sys/prctl/linux/prctl_test.cpp b/libc/test/src/sys/prctl/linux/prctl_test.cpp
index 643c9513b36eb..6278dcec588af 100644
--- a/libc/test/src/sys/prctl/linux/prctl_test.cpp
+++ b/libc/test/src/sys/prctl/linux/prctl_test.cpp
@@ -36,7 +36,7 @@ TEST(LlvmLibcSysPrctlTest, GetTHPDisable) {
   // covered in ErrnoSetterMatcher.
   libc_errno = 0;
   int ret = LIBC_NAMESPACE::prctl(PR_GET_THP_DISABLE, 0, 0, 0, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   // PR_GET_THP_DISABLE return (as the function result) the current
   // setting of the "THP disable" flag for the calling thread, which
   // is either 1, if the flag is set; or 0, if it is not.
diff --git a/libc/test/src/sys/resource/getrlimit_setrlimit_test.cpp b/libc/test/src/sys/resource/getrlimit_setrlimit_test.cpp
index 0870deeeb5d80..1a0d79f4e7527 100644
--- a/libc/test/src/sys/resource/getrlimit_setrlimit_test.cpp
+++ b/libc/test/src/sys/resource/getrlimit_setrlimit_test.cpp
@@ -33,10 +33,10 @@ TEST(LlvmLibcResourceLimitsTest, SetNoFileLimit) {
 
   int fd1 = LIBC_NAMESPACE::open(TEST_FILE1, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(fd1, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   int fd2 = LIBC_NAMESPACE::open(TEST_FILE2, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(fd2, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_THAT(LIBC_NAMESPACE::close(fd1), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd2), Succeeds(0));
@@ -49,20 +49,20 @@ TEST(LlvmLibcResourceLimitsTest, SetNoFileLimit) {
   // One can now only open one of the files successfully.
   fd1 = LIBC_NAMESPACE::open(TEST_FILE1, O_RDONLY);
   ASSERT_GT(fd1, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   fd2 = LIBC_NAMESPACE::open(TEST_FILE2, O_RDONLY);
   ASSERT_LT(fd2, 0);
-  ASSERT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
 
   libc_errno = 0;
   ASSERT_THAT(LIBC_NAMESPACE::close(fd1), Succeeds(0));
 
   fd2 = LIBC_NAMESPACE::open(TEST_FILE2, O_RDONLY);
   ASSERT_GT(fd2, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   fd1 = LIBC_NAMESPACE::open(TEST_FILE1, O_RDONLY);
   ASSERT_LT(fd1, 0);
-  ASSERT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
 
   libc_errno = 0;
   ASSERT_THAT(LIBC_NAMESPACE::close(fd2), Succeeds(0));
diff --git a/libc/test/src/sys/sendfile/sendfile_test.cpp b/libc/test/src/sys/sendfile/sendfile_test.cpp
index 6e4665a1bb96b..5ea9ca8d05c5a 100644
--- a/libc/test/src/sys/sendfile/sendfile_test.cpp
+++ b/libc/test/src/sys/sendfile/sendfile_test.cpp
@@ -39,16 +39,16 @@ TEST(LlvmLibcSendfileTest, CreateAndTransfer) {
 
   int in_fd = LIBC_NAMESPACE::open(IN_FILE, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(in_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::write(in_fd, IN_DATA, IN_SIZE), IN_SIZE);
   ASSERT_THAT(LIBC_NAMESPACE::close(in_fd), Succeeds(0));
 
   in_fd = LIBC_NAMESPACE::open(IN_FILE, O_RDONLY);
   ASSERT_GT(in_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   int out_fd = LIBC_NAMESPACE::open(OUT_FILE, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(out_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ssize_t size = LIBC_NAMESPACE::sendfile(in_fd, out_fd, nullptr, IN_SIZE);
   ASSERT_EQ(size, IN_SIZE);
   ASSERT_THAT(LIBC_NAMESPACE::close(in_fd), Succeeds(0));
@@ -56,7 +56,7 @@ TEST(LlvmLibcSendfileTest, CreateAndTransfer) {
 
   out_fd = LIBC_NAMESPACE::open(OUT_FILE, O_RDONLY);
   ASSERT_GT(out_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   char buf[IN_SIZE];
   ASSERT_EQ(IN_SIZE, LIBC_NAMESPACE::read(out_fd, buf, IN_SIZE));
   ASSERT_EQ(cpp::string_view(buf), cpp::string_view(IN_DATA));
diff --git a/libc/test/src/sys/socket/linux/bind_test.cpp b/libc/test/src/sys/socket/linux/bind_test.cpp
index 5a3a1c227c9b5..305e4889f394e 100644
--- a/libc/test/src/sys/socket/linux/bind_test.cpp
+++ b/libc/test/src/sys/socket/linux/bind_test.cpp
@@ -25,7 +25,7 @@ TEST(LlvmLibcSocketTest, BindLocalSocket) {
 
   int sock = LIBC_NAMESPACE::socket(AF_UNIX, SOCK_DGRAM, 0);
   ASSERT_GE(sock, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   struct sockaddr_un my_addr;
 
@@ -47,7 +47,7 @@ TEST(LlvmLibcSocketTest, BindLocalSocket) {
                            sizeof(struct sockaddr_un));
 
   ASSERT_EQ(result, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   LIBC_NAMESPACE::close(sock);
 
diff --git a/libc/test/src/sys/socket/linux/socket_test.cpp b/libc/test/src/sys/socket/linux/socket_test.cpp
index 9d5bfacde0a40..d1197fa3ef7c6 100644
--- a/libc/test/src/sys/socket/linux/socket_test.cpp
+++ b/libc/test/src/sys/socket/linux/socket_test.cpp
@@ -18,7 +18,7 @@
 TEST(LlvmLibcSocketTest, LocalSocket) {
   int sock = LIBC_NAMESPACE::socket(AF_UNIX, SOCK_DGRAM, 0);
   ASSERT_GE(sock, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   LIBC_NAMESPACE::close(sock);
 }
diff --git a/libc/test/src/sys/stat/chmod_test.cpp b/libc/test/src/sys/stat/chmod_test.cpp
index c476b92b5e437..6fd056b2bd6cc 100644
--- a/libc/test/src/sys/stat/chmod_test.cpp
+++ b/libc/test/src/sys/stat/chmod_test.cpp
@@ -32,25 +32,25 @@ TEST(LlvmLibcChmodTest, ChangeAndOpen) {
 
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_WRONLY);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::write(fd, WRITE_DATA, sizeof(WRITE_DATA)),
             WRITE_SIZE);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_PATH);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
   EXPECT_THAT(LIBC_NAMESPACE::chmod(TEST_FILE, S_IRUSR), Succeeds(0));
 
   // Opening for writing should fail.
   EXPECT_EQ(LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_WRONLY), -1);
-  EXPECT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
   // But opening for reading should succeed.
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_RDONLY);
   EXPECT_GT(fd, 0);
-  EXPECT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   EXPECT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
   EXPECT_THAT(LIBC_NAMESPACE::chmod(TEST_FILE, S_IRWXU), Succeeds(0));
diff --git a/libc/test/src/sys/stat/fchmod_test.cpp b/libc/test/src/sys/stat/fchmod_test.cpp
index 5a32b5c973db9..a0a93b03d22ed 100644
--- a/libc/test/src/sys/stat/fchmod_test.cpp
+++ b/libc/test/src/sys/stat/fchmod_test.cpp
@@ -32,25 +32,25 @@ TEST(LlvmLibcChmodTest, ChangeAndOpen) {
 
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_WRONLY);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::write(fd, WRITE_DATA, sizeof(WRITE_DATA)),
             WRITE_SIZE);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_WRONLY);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   EXPECT_THAT(LIBC_NAMESPACE::fchmod(fd, S_IRUSR), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   // Opening for writing should fail.
   EXPECT_EQ(LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_WRONLY), -1);
-  EXPECT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
   // But opening for reading should succeed.
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_RDONLY);
   EXPECT_GT(fd, 0);
-  EXPECT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   EXPECT_THAT(LIBC_NAMESPACE::fchmod(fd, S_IRWXU), Succeeds(0));
   EXPECT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
@@ -59,6 +59,6 @@ TEST(LlvmLibcChmodTest, ChangeAndOpen) {
 TEST(LlvmLibcChmodTest, NonExistentFile) {
   libc_errno = 0;
   ASSERT_EQ(LIBC_NAMESPACE::fchmod(-1, S_IRUSR), -1);
-  ASSERT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
 }
diff --git a/libc/test/src/sys/stat/fchmodat_test.cpp b/libc/test/src/sys/stat/fchmodat_test.cpp
index 077d21df15af3..e2cf170728ec1 100644
--- a/libc/test/src/sys/stat/fchmodat_test.cpp
+++ b/libc/test/src/sys/stat/fchmodat_test.cpp
@@ -34,26 +34,26 @@ TEST(LlvmLibcFchmodatTest, ChangeAndOpen) {
 
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::write(fd, WRITE_DATA, sizeof(WRITE_DATA)),
             WRITE_SIZE);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   int dirfd = LIBC_NAMESPACE::open(TEST_DIR, O_DIRECTORY);
   ASSERT_GT(dirfd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   EXPECT_THAT(LIBC_NAMESPACE::fchmodat(dirfd, TEST_FILE_BASENAME, S_IRUSR, 0),
               Succeeds(0));
 
   // Opening for writing should fail.
   EXPECT_EQ(LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_WRONLY), -1);
-  EXPECT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
   // But opening for reading should succeed.
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_RDONLY);
   EXPECT_GT(fd, 0);
-  EXPECT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   EXPECT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
   EXPECT_THAT(LIBC_NAMESPACE::fchmodat(dirfd, TEST_FILE_BASENAME, S_IRWXU, 0),
diff --git a/libc/test/src/sys/stat/fstat_test.cpp b/libc/test/src/sys/stat/fstat_test.cpp
index 22e407f6d791b..33769ea1f05af 100644
--- a/libc/test/src/sys/stat/fstat_test.cpp
+++ b/libc/test/src/sys/stat/fstat_test.cpp
@@ -30,7 +30,7 @@ TEST(LlvmLibcFStatTest, CreatAndReadMode) {
 
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   struct stat statbuf;
   ASSERT_THAT(LIBC_NAMESPACE::fstat(fd, &statbuf), Succeeds(0));
diff --git a/libc/test/src/sys/stat/lstat_test.cpp b/libc/test/src/sys/stat/lstat_test.cpp
index 6eae08daeb1cf..a3b3c2cb0c1df 100644
--- a/libc/test/src/sys/stat/lstat_test.cpp
+++ b/libc/test/src/sys/stat/lstat_test.cpp
@@ -30,7 +30,7 @@ TEST(LlvmLibcLStatTest, CreatAndReadMode) {
 
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   struct stat statbuf;
diff --git a/libc/test/src/sys/stat/stat_test.cpp b/libc/test/src/sys/stat/stat_test.cpp
index 1711c860df269..1286e12fd6110 100644
--- a/libc/test/src/sys/stat/stat_test.cpp
+++ b/libc/test/src/sys/stat/stat_test.cpp
@@ -30,7 +30,7 @@ TEST(LlvmLibcStatTest, CreatAndReadMode) {
 
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_WRONLY, S_IRWXU);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   struct stat statbuf;
diff --git a/libc/test/src/termios/termios_test.cpp b/libc/test/src/termios/termios_test.cpp
index 3048f9cda1e05..790c010c5b7eb 100644
--- a/libc/test/src/termios/termios_test.cpp
+++ b/libc/test/src/termios/termios_test.cpp
@@ -48,7 +48,7 @@ TEST(LlvmLibcTermiosTest, GetAttrSmokeTest) {
   int fd = LIBC_NAMESPACE::open("/dev/tty", O_RDONLY);
   if (fd < 0)
     return; // When /dev/tty is not available, no point continuing.
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::tcgetattr(fd, &t), Succeeds(0));
   ASSERT_EQ(LIBC_NAMESPACE::close(fd), 0);
 }
@@ -58,7 +58,7 @@ TEST(LlvmLibcTermiosTest, TcGetSidSmokeTest) {
   int fd = LIBC_NAMESPACE::open("/dev/tty", O_RDONLY);
   if (fd < 0)
     return; // When /dev/tty is not available, no point continuing.
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(LIBC_NAMESPACE::tcgetsid(fd), pid_t(0));
   ASSERT_EQ(LIBC_NAMESPACE::close(fd), 0);
 }
diff --git a/libc/test/src/time/gmtime_test.cpp b/libc/test/src/time/gmtime_test.cpp
index e59daf012d9b6..d4bcc7d5831e9 100644
--- a/libc/test/src/time/gmtime_test.cpp
+++ b/libc/test/src/time/gmtime_test.cpp
@@ -26,7 +26,7 @@ TEST(LlvmLibcGmTime, OutOfRange) {
                         TimeConstants::NUMBER_OF_SECONDS_IN_LEAP_YEAR);
   struct tm *tm_data = LIBC_NAMESPACE::gmtime(&seconds);
   EXPECT_TRUE(tm_data == nullptr);
-  EXPECT_EQ(libc_errno, EOVERFLOW);
+  ASSERT_ERRNO_EQ(EOVERFLOW);
 
   libc_errno = 0;
   seconds = INT_MIN * static_cast<int64_t>(
@@ -34,7 +34,7 @@ TEST(LlvmLibcGmTime, OutOfRange) {
             1;
   tm_data = LIBC_NAMESPACE::gmtime(&seconds);
   EXPECT_TRUE(tm_data == nullptr);
-  EXPECT_EQ(libc_errno, EOVERFLOW);
+  ASSERT_ERRNO_EQ(EOVERFLOW);
 }
 
 TEST(LlvmLibcGmTime, InvalidSeconds) {
diff --git a/libc/test/src/time/nanosleep_test.cpp b/libc/test/src/time/nanosleep_test.cpp
index 2826ed14dfeda..8baaa29df4785 100644
--- a/libc/test/src/time/nanosleep_test.cpp
+++ b/libc/test/src/time/nanosleep_test.cpp
@@ -23,6 +23,6 @@ TEST(LlvmLibcNanosleep, SmokeTest) {
   struct timespec tim = {1, 500};
   struct timespec tim2 = {0, 0};
   int ret = LIBC_NAMESPACE::nanosleep(&tim, &tim2);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(ret, 0);
 }
diff --git a/libc/test/src/unistd/access_test.cpp b/libc/test/src/unistd/access_test.cpp
index 7d4b3be443fed..6718005846026 100644
--- a/libc/test/src/unistd/access_test.cpp
+++ b/libc/test/src/unistd/access_test.cpp
@@ -24,29 +24,29 @@ TEST(LlvmLibcAccessTest, CreateAndTest) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/access.test";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   ASSERT_EQ(LIBC_NAMESPACE::access(TEST_FILE, F_OK), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::access(TEST_FILE, X_OK | W_OK | R_OK), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IXUSR);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
   ASSERT_EQ(LIBC_NAMESPACE::access(TEST_FILE, F_OK), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::access(TEST_FILE, X_OK), 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(LIBC_NAMESPACE::access(TEST_FILE, R_OK), -1);
-  ASSERT_EQ(libc_errno, EACCES);
+  ASSERT_ERRNO_EQ(EACCES);
   libc_errno = 0;
   ASSERT_EQ(LIBC_NAMESPACE::access(TEST_FILE, W_OK), -1);
-  ASSERT_EQ(libc_errno, EACCES);
+  ASSERT_ERRNO_EQ(EACCES);
   libc_errno = 0;
   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
 }
diff --git a/libc/test/src/unistd/chdir_test.cpp b/libc/test/src/unistd/chdir_test.cpp
index dfdeacdc8e42a..6676b71eed732 100644
--- a/libc/test/src/unistd/chdir_test.cpp
+++ b/libc/test/src/unistd/chdir_test.cpp
@@ -28,13 +28,13 @@ TEST(LlvmLibcChdirTest, ChangeAndOpen) {
 
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_PATH);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   ASSERT_THAT(LIBC_NAMESPACE::chdir(TEST_DIR), Succeeds(0));
   fd = LIBC_NAMESPACE::open(TEST_FILE_BASE, O_PATH);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 }
 
diff --git a/libc/test/src/unistd/dup2_test.cpp b/libc/test/src/unistd/dup2_test.cpp
index d46c4b919ce72..70ea1a72bc8e4 100644
--- a/libc/test/src/unistd/dup2_test.cpp
+++ b/libc/test/src/unistd/dup2_test.cpp
@@ -24,10 +24,10 @@ TEST(LlvmLibcdupTest, ReadAndWriteViaDup) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/dup2.test";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   int dupfd = LIBC_NAMESPACE::dup2(fd, DUPFD);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(dupfd, DUPFD);
 
   // Write something via the dup
@@ -39,10 +39,10 @@ TEST(LlvmLibcdupTest, ReadAndWriteViaDup) {
 
   // Reopen the file for reading and create a dup.
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   dupfd = LIBC_NAMESPACE::dup2(fd, DUPFD);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(dupfd, DUPFD);
 
   // Read the file content via the dup.
diff --git a/libc/test/src/unistd/dup3_test.cpp b/libc/test/src/unistd/dup3_test.cpp
index d2d544d5d9a12..9c13de47f0be4 100644
--- a/libc/test/src/unistd/dup3_test.cpp
+++ b/libc/test/src/unistd/dup3_test.cpp
@@ -30,10 +30,10 @@ TEST(LlvmLibcdupTest, ReadAndWriteViaDup) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/dup3.test";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   int dupfd = LIBC_NAMESPACE::dup3(fd, DUPFD, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(dupfd, DUPFD);
 
   // Write something via the dup
@@ -45,10 +45,10 @@ TEST(LlvmLibcdupTest, ReadAndWriteViaDup) {
 
   // Reopen the file for reading and create a dup.
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   dupfd = LIBC_NAMESPACE::dup3(fd, DUPFD, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(dupfd, DUPFD);
 
   // Read the file content via the dup.
diff --git a/libc/test/src/unistd/dup_test.cpp b/libc/test/src/unistd/dup_test.cpp
index 856b004fbe65d..23abf5969fc28 100644
--- a/libc/test/src/unistd/dup_test.cpp
+++ b/libc/test/src/unistd/dup_test.cpp
@@ -23,10 +23,10 @@ TEST(LlvmLibcdupTest, ReadAndWriteViaDup) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/dup.test";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   int dupfd = LIBC_NAMESPACE::dup(fd);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(dupfd, 0);
 
   // Write something via the dup
@@ -38,10 +38,10 @@ TEST(LlvmLibcdupTest, ReadAndWriteViaDup) {
 
   // Reopen the file for reading and create a dup.
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   dupfd = LIBC_NAMESPACE::dup(fd);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(dupfd, 0);
 
   // Read the file content via the dup.
diff --git a/libc/test/src/unistd/fchdir_test.cpp b/libc/test/src/unistd/fchdir_test.cpp
index 27d4489f6447e..0d870e35f51c5 100644
--- a/libc/test/src/unistd/fchdir_test.cpp
+++ b/libc/test/src/unistd/fchdir_test.cpp
@@ -28,16 +28,16 @@ TEST(LlvmLibcChdirTest, ChangeAndOpen) {
 
   int dir_fd = LIBC_NAMESPACE::open(TEST_DIR, O_DIRECTORY);
   ASSERT_GT(dir_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   int file_fd = LIBC_NAMESPACE::open(TEST_FILE, O_PATH);
   ASSERT_GT(file_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(file_fd), Succeeds(0));
 
   ASSERT_THAT(LIBC_NAMESPACE::fchdir(dir_fd), Succeeds(0));
   file_fd = LIBC_NAMESPACE::open(TEST_FILE_BASE, O_PATH);
   ASSERT_GT(file_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(file_fd), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::close(dir_fd), Succeeds(0));
 }
@@ -46,6 +46,6 @@ TEST(LlvmLibcChdirTest, ChangeToNonExistentDir) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
   libc_errno = 0;
   ASSERT_EQ(LIBC_NAMESPACE::fchdir(0), -1);
-  ASSERT_NE(libc_errno, 0);
+  ASSERT_ERRNO_FAILURE();
   libc_errno = 0;
 }
diff --git a/libc/test/src/unistd/ftruncate_test.cpp b/libc/test/src/unistd/ftruncate_test.cpp
index fc68348e32ec6..50a3508e0a872 100644
--- a/libc/test/src/unistd/ftruncate_test.cpp
+++ b/libc/test/src/unistd/ftruncate_test.cpp
@@ -35,14 +35,14 @@ TEST(LlvmLibcFtruncateTest, CreateAndTruncate) {
   //   4. Try to read more than 1 byte and fail.
   libc_errno = 0;
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_EQ(ssize_t(WRITE_SIZE),
             LIBC_NAMESPACE::write(fd, WRITE_DATA, WRITE_SIZE));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_EQ(ssize_t(WRITE_SIZE), LIBC_NAMESPACE::read(fd, buf, WRITE_SIZE));
   ASSERT_EQ(cpp::string_view(buf), cpp::string_view(WRITE_DATA));
@@ -52,12 +52,12 @@ TEST(LlvmLibcFtruncateTest, CreateAndTruncate) {
   // writing.
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY);
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::ftruncate(fd, off_t(1)), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_EQ(ssize_t(1), LIBC_NAMESPACE::read(fd, buf, WRITE_SIZE));
   ASSERT_EQ(buf[0], WRITE_DATA[0]);
diff --git a/libc/test/src/unistd/isatty_test.cpp b/libc/test/src/unistd/isatty_test.cpp
index 7bf8dd708bfa6..c0e14c344b436 100644
--- a/libc/test/src/unistd/isatty_test.cpp
+++ b/libc/test/src/unistd/isatty_test.cpp
@@ -43,7 +43,7 @@ TEST(LlvmLibcIsATTYTest, DevTTYTest) {
   libc_errno = 0;
   int fd = LIBC_NAMESPACE::open(TTY_FILE, O_RDONLY);
   if (fd > 0) {
-    ASSERT_EQ(libc_errno, 0);
+    ASSERT_ERRNO_SUCCESS();
     EXPECT_THAT(LIBC_NAMESPACE::isatty(fd), Succeeds(1));
     ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
   }
@@ -53,7 +53,7 @@ TEST(LlvmLibcIsATTYTest, FileTest) {
   constexpr const char *TEST_FILE = "testdata/isatty.test";
   libc_errno = 0;
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   EXPECT_THAT(LIBC_NAMESPACE::isatty(fd), Fails(ENOTTY, 0));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
diff --git a/libc/test/src/unistd/link_test.cpp b/libc/test/src/unistd/link_test.cpp
index 2d5aa7588b08b..bf6962b397b2c 100644
--- a/libc/test/src/unistd/link_test.cpp
+++ b/libc/test/src/unistd/link_test.cpp
@@ -28,14 +28,14 @@ TEST(LlvmLibcLinkTest, CreateAndUnlink) {
   //   4. Cleanup the file and its link.
   libc_errno = 0;
   int write_fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::link(TEST_FILE, TEST_FILE_LINK), Succeeds(0));
 
   int link_fd = LIBC_NAMESPACE::open(TEST_FILE_LINK, O_PATH);
   ASSERT_GT(link_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(link_fd), Succeeds(0));
 
   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
diff --git a/libc/test/src/unistd/linkat_test.cpp b/libc/test/src/unistd/linkat_test.cpp
index d1ffe37d63b48..62fbaacac08e4 100644
--- a/libc/test/src/unistd/linkat_test.cpp
+++ b/libc/test/src/unistd/linkat_test.cpp
@@ -32,7 +32,7 @@ TEST(LlvmLibcLinkatTest, CreateAndUnlink) {
   libc_errno = 0;
   int write_fd =
       LIBC_NAMESPACE::open(TEST_FILE_PATH, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
 
@@ -43,7 +43,7 @@ TEST(LlvmLibcLinkatTest, CreateAndUnlink) {
 
   int link_fd = LIBC_NAMESPACE::open(TEST_FILE_LINK_PATH, O_PATH);
   ASSERT_GT(link_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(link_fd), Succeeds(0));
 
   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE_PATH), Succeeds(0));
diff --git a/libc/test/src/unistd/lseek_test.cpp b/libc/test/src/unistd/lseek_test.cpp
index 1a13d54dbc232..fd73bccf0cb8f 100644
--- a/libc/test/src/unistd/lseek_test.cpp
+++ b/libc/test/src/unistd/lseek_test.cpp
@@ -20,7 +20,7 @@ TEST(LlvmLibcUniStd, LseekTest) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/lseek.test";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   constexpr const char LSEEK_TEST[] = "lseek test";
   constexpr int LSEEK_TEST_SIZE = sizeof(LSEEK_TEST) - 1;
@@ -54,7 +54,7 @@ TEST(LlvmLibcUniStd, LseekFailsTest) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/lseek.test";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   EXPECT_THAT(LIBC_NAMESPACE::lseek(fd, -1, SEEK_CUR), Fails(EINVAL));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
diff --git a/libc/test/src/unistd/pread_pwrite_test.cpp b/libc/test/src/unistd/pread_pwrite_test.cpp
index f90d1341c2010..1d17778e550f8 100644
--- a/libc/test/src/unistd/pread_pwrite_test.cpp
+++ b/libc/test/src/unistd/pread_pwrite_test.cpp
@@ -34,7 +34,7 @@ TEST(LlvmLibcUniStd, PWriteAndPReadBackTest) {
 
   constexpr const char *TEST_FILE = "testdata/pread_pwrite.test";
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::write(fd, HELLO, HELLO_SIZE),
               Succeeds(HELLO_SIZE));
@@ -42,7 +42,7 @@ TEST(LlvmLibcUniStd, PWriteAndPReadBackTest) {
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::pwrite(fd, HELLO, HELLO_SIZE, OFFSET),
               Succeeds(HELLO_SIZE));
@@ -50,7 +50,7 @@ TEST(LlvmLibcUniStd, PWriteAndPReadBackTest) {
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   char read_buf[OFFSET_TEXT_SIZE];
   ASSERT_THAT(LIBC_NAMESPACE::pread(fd, read_buf, HELLO_SIZE, OFFSET),
diff --git a/libc/test/src/unistd/read_write_test.cpp b/libc/test/src/unistd/read_write_test.cpp
index 3007d4c387115..1330573582209 100644
--- a/libc/test/src/unistd/read_write_test.cpp
+++ b/libc/test/src/unistd/read_write_test.cpp
@@ -21,7 +21,7 @@ TEST(LlvmLibcUniStd, WriteAndReadBackTest) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "__unistd_read_write.test";
   int write_fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
   constexpr const char HELLO[] = "hello";
   constexpr int HELLO_SIZE = sizeof(HELLO);
@@ -31,7 +31,7 @@ TEST(LlvmLibcUniStd, WriteAndReadBackTest) {
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
 
   int read_fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(read_fd, 0);
   char read_buf[10];
   ASSERT_THAT(LIBC_NAMESPACE::read(read_fd, read_buf, HELLO_SIZE),
diff --git a/libc/test/src/unistd/readlink_test.cpp b/libc/test/src/unistd/readlink_test.cpp
index b2d018a50ec79..19b339ec2b374 100644
--- a/libc/test/src/unistd/readlink_test.cpp
+++ b/libc/test/src/unistd/readlink_test.cpp
@@ -30,7 +30,7 @@ TEST(LlvmLibcReadlinkTest, CreateAndUnlink) {
 
   char buf[sizeof(LINK_VAL)];
   ssize_t len = LIBC_NAMESPACE::readlink(LINK, buf, sizeof(buf));
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(cpp::string_view(buf, len), cpp::string_view(LINK_VAL));
 
   ASSERT_THAT(LIBC_NAMESPACE::unlink(LINK), Succeeds(0));
diff --git a/libc/test/src/unistd/readlinkat_test.cpp b/libc/test/src/unistd/readlinkat_test.cpp
index 19f0ceec3cf7c..85cbca084778d 100644
--- a/libc/test/src/unistd/readlinkat_test.cpp
+++ b/libc/test/src/unistd/readlinkat_test.cpp
@@ -32,7 +32,7 @@ TEST(LlvmLibcReadlinkatTest, CreateAndUnlink) {
 
   char buf[sizeof(LINK_VAL)];
   ssize_t len = LIBC_NAMESPACE::readlinkat(AT_FDCWD, LINK, buf, sizeof(buf));
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_EQ(cpp::string_view(buf, len), cpp::string_view(LINK_VAL));
 
   ASSERT_THAT(LIBC_NAMESPACE::unlink(LINK), Succeeds(0));
diff --git a/libc/test/src/unistd/symlink_test.cpp b/libc/test/src/unistd/symlink_test.cpp
index b25cfa4f85769..e0c5979a60876 100644
--- a/libc/test/src/unistd/symlink_test.cpp
+++ b/libc/test/src/unistd/symlink_test.cpp
@@ -29,7 +29,7 @@ TEST(LlvmLibcSymlinkTest, CreateAndUnlink) {
   //   4. Cleanup the file and its symlink.
   libc_errno = 0;
   int write_fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
 
@@ -38,7 +38,7 @@ TEST(LlvmLibcSymlinkTest, CreateAndUnlink) {
 
   int symlink_fd = LIBC_NAMESPACE::open(TEST_FILE_LINK, O_PATH);
   ASSERT_GT(symlink_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(symlink_fd), Succeeds(0));
 
   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
diff --git a/libc/test/src/unistd/symlinkat_test.cpp b/libc/test/src/unistd/symlinkat_test.cpp
index 8aba2daee8cf3..1ab4dc8417d6c 100644
--- a/libc/test/src/unistd/symlinkat_test.cpp
+++ b/libc/test/src/unistd/symlinkat_test.cpp
@@ -32,7 +32,7 @@ TEST(LlvmLibcSymlinkatTest, CreateAndUnlink) {
   libc_errno = 0;
   int write_fd =
       LIBC_NAMESPACE::open(TEST_FILE_PATH, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
 
@@ -42,7 +42,7 @@ TEST(LlvmLibcSymlinkatTest, CreateAndUnlink) {
 
   int link_fd = LIBC_NAMESPACE::open(TEST_FILE_LINK_PATH, O_PATH);
   ASSERT_GT(link_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_THAT(LIBC_NAMESPACE::close(link_fd), Succeeds(0));
 
   ASSERT_THAT(LIBC_NAMESPACE::close(dir_fd), Succeeds(0));
diff --git a/libc/test/src/unistd/syscall_test.cpp b/libc/test/src/unistd/syscall_test.cpp
index 6a5ca47f8d494..aabbffc20d1ba 100644
--- a/libc/test/src/unistd/syscall_test.cpp
+++ b/libc/test/src/unistd/syscall_test.cpp
@@ -30,7 +30,7 @@ TEST(LlvmLibcSyscallTest, TrivialCall) {
   libc_errno = 0;
 
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_gettid), 0l);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 }
 
 TEST(LlvmLibcSyscallTest, SymlinkCreateDestroy) {
@@ -45,7 +45,7 @@ TEST(LlvmLibcSyscallTest, SymlinkCreateDestroy) {
 #else
 #error "symlink and symlinkat syscalls not available."
 #endif
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   char buf[sizeof(LINK_VAL)];
 
@@ -56,7 +56,7 @@ TEST(LlvmLibcSyscallTest, SymlinkCreateDestroy) {
       LIBC_NAMESPACE::syscall(SYS_readlinkat, AT_FDCWD, LINK, buf, sizeof(buf)),
       0l);
 #endif
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
 #ifdef SYS_unlink
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_unlink, LINK), 0l);
@@ -65,7 +65,7 @@ TEST(LlvmLibcSyscallTest, SymlinkCreateDestroy) {
 #else
 #error "unlink and unlinkat syscalls not available."
 #endif
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 }
 
 TEST(LlvmLibcSyscallTest, FileReadWrite) {
@@ -84,17 +84,17 @@ TEST(LlvmLibcSyscallTest, FileReadWrite) {
 #error "open and openat syscalls not available."
 #endif
   ASSERT_GT(fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_pwrite64, fd, HELLO, HELLO_SIZE, 0),
             0l);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_fsync, fd), 0l);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_close, fd), 0l);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 }
 
 TEST(LlvmLibcSyscallTest, FileLinkCreateDestroy) {
@@ -121,10 +121,10 @@ TEST(LlvmLibcSyscallTest, FileLinkCreateDestroy) {
 #error "open and openat syscalls not available."
 #endif
   ASSERT_GT(write_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_close, write_fd), 0l);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
 #ifdef SYS_open
   int dir_fd = LIBC_NAMESPACE::syscall(SYS_open, TEST_DIR, O_DIRECTORY, 0);
@@ -135,12 +135,12 @@ TEST(LlvmLibcSyscallTest, FileLinkCreateDestroy) {
 #error "open and openat syscalls not available."
 #endif
   ASSERT_GT(dir_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_linkat, dir_fd, TEST_FILE, dir_fd,
                                     TEST_FILE_LINK, 0),
             0l);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 #ifdef SYS_open
   int link_fd =
       LIBC_NAMESPACE::syscall(SYS_open, TEST_FILE_LINK_PATH, O_PATH, 0);
@@ -151,7 +151,7 @@ TEST(LlvmLibcSyscallTest, FileLinkCreateDestroy) {
 #error "open and openat syscalls not available."
 #endif
   ASSERT_GT(link_fd, 0);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
 #ifdef SYS_unlink
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_unlink, TEST_FILE_PATH), 0l);
@@ -161,7 +161,7 @@ TEST(LlvmLibcSyscallTest, FileLinkCreateDestroy) {
 #else
 #error "unlink and unlinkat syscalls not available."
 #endif
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
 #ifdef SYS_unlink
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_unlink, TEST_FILE_LINK_PATH), 0l);
@@ -172,8 +172,8 @@ TEST(LlvmLibcSyscallTest, FileLinkCreateDestroy) {
 #else
 #error "unlink and unlinkat syscalls not available."
 #endif
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 
   ASSERT_GE(LIBC_NAMESPACE::syscall(SYS_close, dir_fd), 0l);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
 }
diff --git a/libc/test/src/unistd/truncate_test.cpp b/libc/test/src/unistd/truncate_test.cpp
index 6d8a3b8e53f72..4d316ed1b16fe 100644
--- a/libc/test/src/unistd/truncate_test.cpp
+++ b/libc/test/src/unistd/truncate_test.cpp
@@ -35,14 +35,14 @@ TEST(LlvmLibcTruncateTest, CreateAndTruncate) {
   //   4. Try to read more than 1 byte and fail.
   libc_errno = 0;
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_EQ(ssize_t(WRITE_SIZE),
             LIBC_NAMESPACE::write(fd, WRITE_DATA, WRITE_SIZE));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_EQ(ssize_t(WRITE_SIZE), LIBC_NAMESPACE::read(fd, buf, WRITE_SIZE));
   ASSERT_EQ(cpp::string_view(buf), cpp::string_view(WRITE_DATA));
@@ -51,7 +51,7 @@ TEST(LlvmLibcTruncateTest, CreateAndTruncate) {
   ASSERT_THAT(LIBC_NAMESPACE::truncate(TEST_FILE, off_t(1)), Succeeds(0));
 
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
   ASSERT_EQ(ssize_t(1), LIBC_NAMESPACE::read(fd, buf, WRITE_SIZE));
   ASSERT_EQ(buf[0], WRITE_DATA[0]);
diff --git a/libc/test/src/unistd/unlink_test.cpp b/libc/test/src/unistd/unlink_test.cpp
index 77f65b5ecc6a1..c2828df65a180 100644
--- a/libc/test/src/unistd/unlink_test.cpp
+++ b/libc/test/src/unistd/unlink_test.cpp
@@ -19,7 +19,7 @@ TEST(LlvmLibcUnlinkTest, CreateAndUnlink) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/unlink.test";
   int write_fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
diff --git a/libc/test/src/unistd/unlinkat_test.cpp b/libc/test/src/unistd/unlinkat_test.cpp
index 22a20bc6ad07b..ac32ed4895d6b 100644
--- a/libc/test/src/unistd/unlinkat_test.cpp
+++ b/libc/test/src/unistd/unlinkat_test.cpp
@@ -21,11 +21,11 @@ TEST(LlvmLibcUnlinkatTest, CreateAndDeleteTest) {
   constexpr const char *TEST_DIR = "testdata";
   constexpr const char *TEST_FILE = "openat.test";
   int dir_fd = LIBC_NAMESPACE::open(TEST_DIR, O_DIRECTORY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(dir_fd, 0);
   int write_fd =
       LIBC_NAMESPACE::openat(dir_fd, TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::unlinkat(dir_fd, TEST_FILE, 0), Succeeds(0));
@@ -35,7 +35,7 @@ TEST(LlvmLibcUnlinkatTest, CreateAndDeleteTest) {
 TEST(LlvmLibcUnlinkatTest, UnlinkatNonExistentFile) {
   constexpr const char *TEST_DIR = "testdata";
   int dir_fd = LIBC_NAMESPACE::open(TEST_DIR, O_DIRECTORY);
-  ASSERT_EQ(libc_errno, 0);
+  ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(dir_fd, 0);
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;