diff --git a/libc/test/src/math/smoke/FModTest.h b/libc/test/src/math/smoke/FModTest.h
index 8fbcc2a276542..e63bbced545b3 100644
--- a/libc/test/src/math/smoke/FModTest.h
+++ b/libc/test/src/math/smoke/FModTest.h
@@ -19,10 +19,10 @@
 
 #define TEST_SPECIAL(x, y, expected, dom_err, expected_exception)              \
   LIBC_NAMESPACE::fputil::clear_except(FE_ALL_EXCEPT);                         \
+  LIBC_NAMESPACE::libc_errno = 0;                                              \
   EXPECT_FP_EQ(expected, f(x, y));                                             \
   EXPECT_MATH_ERRNO((dom_err) ? EDOM : 0);                                     \
-  EXPECT_FP_EXCEPTION(expected_exception);                                     \
-  LIBC_NAMESPACE::fputil::clear_except(FE_ALL_EXCEPT)
+  EXPECT_FP_EXCEPTION(expected_exception)
 
 #define TEST_REGULAR(x, y, expected) TEST_SPECIAL(x, y, expected, false, 0)
 
diff --git a/libc/test/src/sys/epoll/linux/epoll_create1_test.cpp b/libc/test/src/sys/epoll/linux/epoll_create1_test.cpp
index 4059afe16b807..b3b04cd601134 100644
--- a/libc/test/src/sys/epoll/linux/epoll_create1_test.cpp
+++ b/libc/test/src/sys/epoll/linux/epoll_create1_test.cpp
@@ -15,6 +15,7 @@
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
 TEST(LlvmLibcEpollCreate1Test, Basic) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int fd = LIBC_NAMESPACE::epoll_create1(0);
   ASSERT_GT(fd, 0);
   ASSERT_ERRNO_SUCCESS();
@@ -23,6 +24,7 @@ TEST(LlvmLibcEpollCreate1Test, Basic) {
 }
 
 TEST(LlvmLibcEpollCreate1Test, CloseOnExecute) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int fd = LIBC_NAMESPACE::epoll_create1(EPOLL_CLOEXEC);
   ASSERT_GT(fd, 0);
   ASSERT_ERRNO_SUCCESS();
diff --git a/libc/test/src/sys/epoll/linux/epoll_create_test.cpp b/libc/test/src/sys/epoll/linux/epoll_create_test.cpp
index 9c4bad10c8384..8d048d38037b2 100644
--- a/libc/test/src/sys/epoll/linux/epoll_create_test.cpp
+++ b/libc/test/src/sys/epoll/linux/epoll_create_test.cpp
@@ -15,6 +15,7 @@
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
 TEST(LlvmLibcEpollCreateTest, Basic) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int fd = LIBC_NAMESPACE::epoll_create(1);
   ASSERT_GT(fd, 0);
   ASSERT_ERRNO_SUCCESS();
diff --git a/libc/test/src/sys/epoll/linux/epoll_ctl_test.cpp b/libc/test/src/sys/epoll/linux/epoll_ctl_test.cpp
index fa2d358c57966..067b145b95d78 100644
--- a/libc/test/src/sys/epoll/linux/epoll_ctl_test.cpp
+++ b/libc/test/src/sys/epoll/linux/epoll_ctl_test.cpp
@@ -19,6 +19,7 @@
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
 TEST(LlvmLibcEpollCtlTest, Basic) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int epfd = LIBC_NAMESPACE::epoll_create1(0);
   ASSERT_GT(epfd, 0);
   ASSERT_ERRNO_SUCCESS();
diff --git a/libc/test/src/sys/epoll/linux/epoll_pwait2_test.cpp b/libc/test/src/sys/epoll/linux/epoll_pwait2_test.cpp
index 2f4c9854be1a0..1246a3c5a0f06 100644
--- a/libc/test/src/sys/epoll/linux/epoll_pwait2_test.cpp
+++ b/libc/test/src/sys/epoll/linux/epoll_pwait2_test.cpp
@@ -20,6 +20,7 @@
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
 TEST(LlvmLibcEpollPwaitTest, Basic) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int epfd = LIBC_NAMESPACE::epoll_create1(0);
   ASSERT_GT(epfd, 0);
   ASSERT_ERRNO_SUCCESS();
diff --git a/libc/test/src/sys/epoll/linux/epoll_pwait_test.cpp b/libc/test/src/sys/epoll/linux/epoll_pwait_test.cpp
index 8e14aea8b9d57..abfbd4053a526 100644
--- a/libc/test/src/sys/epoll/linux/epoll_pwait_test.cpp
+++ b/libc/test/src/sys/epoll/linux/epoll_pwait_test.cpp
@@ -20,6 +20,7 @@
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
 TEST(LlvmLibcEpollPwaitTest, Basic) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int epfd = LIBC_NAMESPACE::epoll_create1(0);
   ASSERT_GT(epfd, 0);
   ASSERT_ERRNO_SUCCESS();
diff --git a/libc/test/src/sys/epoll/linux/epoll_wait_test.cpp b/libc/test/src/sys/epoll/linux/epoll_wait_test.cpp
index f9e855a891b05..e5b7c89417798 100644
--- a/libc/test/src/sys/epoll/linux/epoll_wait_test.cpp
+++ b/libc/test/src/sys/epoll/linux/epoll_wait_test.cpp
@@ -19,6 +19,7 @@
 using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
 
 TEST(LlvmLibcEpollWaitTest, Basic) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int epfd = LIBC_NAMESPACE::epoll_create1(0);
   ASSERT_GT(epfd, 0);
   ASSERT_ERRNO_SUCCESS();
diff --git a/libc/test/src/sys/socket/linux/send_recv_test.cpp b/libc/test/src/sys/socket/linux/send_recv_test.cpp
index a5d4880d934cc..bc2184e261a5b 100644
--- a/libc/test/src/sys/socket/linux/send_recv_test.cpp
+++ b/libc/test/src/sys/socket/linux/send_recv_test.cpp
@@ -23,17 +23,19 @@ TEST(LlvmLibcSendRecvTest, SucceedsWithSocketPair) {
 
   int sockpair[2] = {0, 0};
 
+  LIBC_NAMESPACE::libc_errno = 0;
   int result = LIBC_NAMESPACE::socketpair(AF_UNIX, SOCK_STREAM, 0, sockpair);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t send_result =
       LIBC_NAMESPACE::send(sockpair[0], TEST_MESSAGE, MESSAGE_LEN, 0);
   EXPECT_EQ(send_result, static_cast<ssize_t>(MESSAGE_LEN));
   ASSERT_ERRNO_SUCCESS();
 
+  LIBC_NAMESPACE::libc_errno = 0;
   char buffer[256];
-
   ssize_t recv_result =
       LIBC_NAMESPACE::recv(sockpair[1], buffer, sizeof(buffer), 0);
   ASSERT_EQ(recv_result, static_cast<ssize_t>(MESSAGE_LEN));
@@ -42,10 +44,12 @@ TEST(LlvmLibcSendRecvTest, SucceedsWithSocketPair) {
   ASSERT_STREQ(buffer, TEST_MESSAGE);
 
   // close both ends of the socket
+  LIBC_NAMESPACE::libc_errno = 0;
   result = LIBC_NAMESPACE::close(sockpair[0]);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
 
+  LIBC_NAMESPACE::libc_errno = 0;
   result = LIBC_NAMESPACE::close(sockpair[1]);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
@@ -55,19 +59,17 @@ TEST(LlvmLibcSendRecvTest, SendFails) {
   const char TEST_MESSAGE[] = "connection terminated";
   const size_t MESSAGE_LEN = sizeof(TEST_MESSAGE);
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t send_result = LIBC_NAMESPACE::send(-1, TEST_MESSAGE, MESSAGE_LEN, 0);
   EXPECT_EQ(send_result, ssize_t(-1));
   ASSERT_ERRNO_FAILURE();
-
-  LIBC_NAMESPACE::libc_errno = 0; // reset errno to avoid test ordering issues.
 }
 
 TEST(LlvmLibcSendRecvTest, RecvFails) {
   char buffer[256];
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t recv_result = LIBC_NAMESPACE::recv(-1, buffer, sizeof(buffer), 0);
   ASSERT_EQ(recv_result, ssize_t(-1));
   ASSERT_ERRNO_FAILURE();
-
-  LIBC_NAMESPACE::libc_errno = 0; // reset errno to avoid test ordering issues.
 }
diff --git a/libc/test/src/sys/socket/linux/sendmsg_recvmsg_test.cpp b/libc/test/src/sys/socket/linux/sendmsg_recvmsg_test.cpp
index abcb0a3e6e506..0ae07e124e5e1 100644
--- a/libc/test/src/sys/socket/linux/sendmsg_recvmsg_test.cpp
+++ b/libc/test/src/sys/socket/linux/sendmsg_recvmsg_test.cpp
@@ -23,6 +23,7 @@ TEST(LlvmLibcSendMsgRecvMsgTest, SucceedsWithSocketPair) {
 
   int sockpair[2] = {0, 0};
 
+  LIBC_NAMESPACE::libc_errno = 0;
   int result = LIBC_NAMESPACE::socketpair(AF_UNIX, SOCK_STREAM, 0, sockpair);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
@@ -41,6 +42,7 @@ TEST(LlvmLibcSendMsgRecvMsgTest, SucceedsWithSocketPair) {
   send_message.msg_controllen = 0;
   send_message.msg_flags = 0;
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t send_result = LIBC_NAMESPACE::sendmsg(sockpair[0], &send_message, 0);
   EXPECT_EQ(send_result, static_cast<ssize_t>(MESSAGE_LEN));
   ASSERT_ERRNO_SUCCESS();
@@ -60,6 +62,7 @@ TEST(LlvmLibcSendMsgRecvMsgTest, SucceedsWithSocketPair) {
   recv_message.msg_controllen = 0;
   recv_message.msg_flags = 0;
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t recv_result = LIBC_NAMESPACE::recvmsg(sockpair[1], &recv_message, 0);
   ASSERT_EQ(recv_result, static_cast<ssize_t>(MESSAGE_LEN));
   ASSERT_ERRNO_SUCCESS();
@@ -67,10 +70,12 @@ TEST(LlvmLibcSendMsgRecvMsgTest, SucceedsWithSocketPair) {
   ASSERT_STREQ(buffer, TEST_MESSAGE);
 
   // close both ends of the socket
+  LIBC_NAMESPACE::libc_errno = 0;
   result = LIBC_NAMESPACE::close(sockpair[0]);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
 
+  LIBC_NAMESPACE::libc_errno = 0;
   result = LIBC_NAMESPACE::close(sockpair[1]);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
@@ -94,11 +99,10 @@ TEST(LlvmLibcSendMsgRecvMsgTest, SendFails) {
   send_message.msg_controllen = 0;
   send_message.msg_flags = 0;
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t send_result = LIBC_NAMESPACE::sendmsg(-1, &send_message, 0);
   EXPECT_EQ(send_result, ssize_t(-1));
   ASSERT_ERRNO_FAILURE();
-
-  LIBC_NAMESPACE::libc_errno = 0; // reset errno to avoid test ordering issues.
 }
 
 TEST(LlvmLibcSendMsgRecvMsgTest, RecvFails) {
@@ -117,9 +121,8 @@ TEST(LlvmLibcSendMsgRecvMsgTest, RecvFails) {
   recv_message.msg_controllen = 0;
   recv_message.msg_flags = 0;
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t recv_result = LIBC_NAMESPACE::recvmsg(-1, &recv_message, 0);
   ASSERT_EQ(recv_result, ssize_t(-1));
   ASSERT_ERRNO_FAILURE();
-
-  LIBC_NAMESPACE::libc_errno = 0; // reset errno to avoid test ordering issues.
 }
diff --git a/libc/test/src/sys/socket/linux/sendto_recvfrom_test.cpp b/libc/test/src/sys/socket/linux/sendto_recvfrom_test.cpp
index e91b333deac58..cca5ceb1ec90f 100644
--- a/libc/test/src/sys/socket/linux/sendto_recvfrom_test.cpp
+++ b/libc/test/src/sys/socket/linux/sendto_recvfrom_test.cpp
@@ -23,10 +23,12 @@ TEST(LlvmLibcSendToRecvFromTest, SucceedsWithSocketPair) {
 
   int sockpair[2] = {0, 0};
 
+  LIBC_NAMESPACE::libc_errno = 0;
   int result = LIBC_NAMESPACE::socketpair(AF_UNIX, SOCK_STREAM, 0, sockpair);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t send_result = LIBC_NAMESPACE::sendto(sockpair[0], TEST_MESSAGE,
                                                MESSAGE_LEN, 0, nullptr, 0);
   EXPECT_EQ(send_result, static_cast<ssize_t>(MESSAGE_LEN));
@@ -34,6 +36,7 @@ TEST(LlvmLibcSendToRecvFromTest, SucceedsWithSocketPair) {
 
   char buffer[256];
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t recv_result = LIBC_NAMESPACE::recvfrom(sockpair[1], buffer,
                                                  sizeof(buffer), 0, nullptr, 0);
   ASSERT_EQ(recv_result, static_cast<ssize_t>(MESSAGE_LEN));
@@ -42,10 +45,12 @@ TEST(LlvmLibcSendToRecvFromTest, SucceedsWithSocketPair) {
   ASSERT_STREQ(buffer, TEST_MESSAGE);
 
   // close both ends of the socket
+  LIBC_NAMESPACE::libc_errno = 0;
   result = LIBC_NAMESPACE::close(sockpair[0]);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
 
+  LIBC_NAMESPACE::libc_errno = 0;
   result = LIBC_NAMESPACE::close(sockpair[1]);
   ASSERT_EQ(result, 0);
   ASSERT_ERRNO_SUCCESS();
@@ -55,21 +60,19 @@ TEST(LlvmLibcSendToRecvFromTest, SendToFails) {
   const char TEST_MESSAGE[] = "connection terminated";
   const size_t MESSAGE_LEN = sizeof(TEST_MESSAGE);
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t send_result =
       LIBC_NAMESPACE::sendto(-1, TEST_MESSAGE, MESSAGE_LEN, 0, nullptr, 0);
   EXPECT_EQ(send_result, ssize_t(-1));
   ASSERT_ERRNO_FAILURE();
-
-  LIBC_NAMESPACE::libc_errno = 0; // reset errno to avoid test ordering issues.
 }
 
 TEST(LlvmLibcSendToRecvFromTest, RecvFromFails) {
   char buffer[256];
 
+  LIBC_NAMESPACE::libc_errno = 0;
   ssize_t recv_result =
       LIBC_NAMESPACE::recvfrom(-1, buffer, sizeof(buffer), 0, nullptr, 0);
   ASSERT_EQ(recv_result, ssize_t(-1));
   ASSERT_ERRNO_FAILURE();
-
-  LIBC_NAMESPACE::libc_errno = 0; // reset errno to avoid test ordering issues.
 }
diff --git a/libc/test/src/sys/socket/linux/socket_test.cpp b/libc/test/src/sys/socket/linux/socket_test.cpp
index d1197fa3ef7c6..63a8783452bb9 100644
--- a/libc/test/src/sys/socket/linux/socket_test.cpp
+++ b/libc/test/src/sys/socket/linux/socket_test.cpp
@@ -16,6 +16,7 @@
 #include <sys/socket.h> // For AF_UNIX and SOCK_DGRAM
 
 TEST(LlvmLibcSocketTest, LocalSocket) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int sock = LIBC_NAMESPACE::socket(AF_UNIX, SOCK_DGRAM, 0);
   ASSERT_GE(sock, 0);
   ASSERT_ERRNO_SUCCESS();
diff --git a/libc/test/src/sys/socket/linux/socketpair_test.cpp b/libc/test/src/sys/socket/linux/socketpair_test.cpp
index 9393ddd5c19d8..bc530696485af 100644
--- a/libc/test/src/sys/socket/linux/socketpair_test.cpp
+++ b/libc/test/src/sys/socket/linux/socketpair_test.cpp
@@ -16,6 +16,7 @@
 #include <sys/socket.h> // For AF_UNIX and SOCK_DGRAM
 
 TEST(LlvmLibcSocketPairTest, LocalSocket) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int sockpair[2] = {-1, -1};
   int result = LIBC_NAMESPACE::socketpair(AF_UNIX, SOCK_DGRAM, 0, sockpair);
   ASSERT_EQ(result, 0);
@@ -24,12 +25,14 @@ TEST(LlvmLibcSocketPairTest, LocalSocket) {
   ASSERT_GE(sockpair[0], 0);
   ASSERT_GE(sockpair[1], 0);
 
+  LIBC_NAMESPACE::libc_errno = 0;
   LIBC_NAMESPACE::close(sockpair[0]);
   LIBC_NAMESPACE::close(sockpair[1]);
   ASSERT_ERRNO_SUCCESS();
 }
 
 TEST(LlvmLibcSocketPairTest, SocketFails) {
+  LIBC_NAMESPACE::libc_errno = 0;
   int sockpair[2] = {-1, -1};
   int result = LIBC_NAMESPACE::socketpair(-1, -1, -1, sockpair);
   ASSERT_EQ(result, -1);
diff --git a/libc/test/src/unistd/pread_pwrite_test.cpp b/libc/test/src/unistd/pread_pwrite_test.cpp
index 397a0da1327a5..b777e91c4e90a 100644
--- a/libc/test/src/unistd/pread_pwrite_test.cpp
+++ b/libc/test/src/unistd/pread_pwrite_test.cpp
@@ -34,6 +34,7 @@ TEST(LlvmLibcUniStd, PWriteAndPReadBackTest) {
 
   constexpr const char *FILENAME = "pread_pwrite.test";
   auto TEST_FILE = libc_make_test_file_path(FILENAME);
+  LIBC_NAMESPACE::libc_errno = 0;
   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
@@ -42,6 +43,7 @@ TEST(LlvmLibcUniStd, PWriteAndPReadBackTest) {
   ASSERT_THAT(LIBC_NAMESPACE::fsync(fd), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
+  LIBC_NAMESPACE::libc_errno = 0;
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
@@ -50,6 +52,7 @@ TEST(LlvmLibcUniStd, PWriteAndPReadBackTest) {
   ASSERT_THAT(LIBC_NAMESPACE::fsync(fd), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
 
+  LIBC_NAMESPACE::libc_errno = 0;
   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(fd, 0);
diff --git a/libc/test/src/unistd/read_write_test.cpp b/libc/test/src/unistd/read_write_test.cpp
index ba3aeff02042d..958e126b8fe9f 100644
--- a/libc/test/src/unistd/read_write_test.cpp
+++ b/libc/test/src/unistd/read_write_test.cpp
@@ -23,6 +23,7 @@ TEST(LlvmLibcUniStd, WriteAndReadBackTest) {
   constexpr const char *FILENAME = "__unistd_read_write.test";
   auto TEST_FILE = libc_make_test_file_path(FILENAME);
 
+  LIBC_NAMESPACE::libc_errno = 0;
   int write_fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);
@@ -33,6 +34,7 @@ TEST(LlvmLibcUniStd, WriteAndReadBackTest) {
   ASSERT_THAT(LIBC_NAMESPACE::fsync(write_fd), Succeeds(0));
   ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
 
+  LIBC_NAMESPACE::libc_errno = 0;
   int read_fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(read_fd, 0);
diff --git a/libc/test/src/unistd/unlink_test.cpp b/libc/test/src/unistd/unlink_test.cpp
index e1ffaab78147e..6e51ec145d5a8 100644
--- a/libc/test/src/unistd/unlink_test.cpp
+++ b/libc/test/src/unistd/unlink_test.cpp
@@ -19,6 +19,7 @@ TEST(LlvmLibcUnlinkTest, CreateAndUnlink) {
   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *FILENAME = "unlink.test";
   auto TEST_FILE = libc_make_test_file_path(FILENAME);
+  LIBC_NAMESPACE::libc_errno = 0;
   int write_fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(write_fd, 0);