diff --git a/CMakeLists.txt b/CMakeLists.txt
index a7d422d3646..886c6366043 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,6 +33,7 @@ option(S2N_LTO, "Enables link time optimizations when building s2n-tls." OFF)
 option(S2N_STACKTRACE "Enables stacktrace functionality in s2n-tls. Note that this functionality is
 only available on platforms that support execinfo." ON)
 option(COVERAGE "Enable profiling collection for code coverage calculation" OFF)
+option(BUILD_TESTING "Build tests for s2n-tls. By default only unit tests are built." ON)
 option(S2N_INTEG_TESTS "Enable the integrationv2 tests" OFF)
 option(S2N_FAST_INTEG_TESTS "Enable the integrationv2 with more parallelism, only has effect if S2N_INTEG_TESTS=ON" ON)
 option(S2N_INSTALL_S2NC_S2ND "Install the binaries s2nc and s2nd" OFF)
@@ -41,9 +42,6 @@ option(TSAN "Enable ThreadSanitizer to test thread safety" OFF)
 option(ASAN "Enable AddressSanitizer to test memory safety" OFF)
 option(SECCOMP "Link with seccomp and run seccomp tests" OFF)
 
-# Turn BUILD_TESTING=ON by default
-include(CTest)
-
 file(GLOB API_HEADERS "api/*.h")
 file(GLOB API_UNSTABLE_HEADERS "api/unstable/*.h")
 
@@ -497,6 +495,29 @@ if (BUILD_TESTING)
     ########################## configure unit tests ############################
     ############################################################################
 
+    # CTest configuration variables need to be set before include(CTest) is called
+    set(VALGRIND_DEFAULT " \
+        --leak-check=full \
+        --leak-resolution=high \
+        --trace-children=yes \
+        -q --error-exitcode=123 \
+        --error-limit=no \
+        --num-callers=40 \
+        --undef-value-errors=no \
+        --log-fd=2 \
+        --suppressions=valgrind.suppressions")
+
+    # "pedantic valgrind" will error on memory that is "Still Reachable". 
+    # We only run this on OpenSSL 1.1.1 because there are hundreds of false positives in other libcryptos.
+    # Tracking issue: https://github.com/aws/s2n-tls/issues/4777
+    if ($ENV{S2N_LIBCRYPTO} MATCHES "openssl-1.1.1")
+        set(MEMORYCHECK_COMMAND_OPTIONS "${VALGRIND_DEFAULT} --run-libc-freeres=yes --errors-for-leak-kinds=all --show-leak-kinds=all")
+    else()
+        set(MEMORYCHECK_COMMAND_OPTIONS "${VALGRIND_DEFAULT} --run-libc-freeres=no")
+    endif()
+
+    set(MEMORYCHECK_TYPE "Valgrind")
+
     set(UNIT_TEST_ENVS S2N_DONT_MLOCK=1)
     if (TSAN OR ASAN)
         set(UNIT_TEST_ENVS ${UNIT_TEST_ENVS} S2N_ADDRESS_SANITIZER=1)
@@ -525,6 +546,8 @@ if (BUILD_TESTING)
     endif()
     message(STATUS "Running tests with environment: ${UNIT_TEST_ENVS}")
 
+    include(CTest)
+
     ############################################################################
     ############################ build unit tests ##############################
     ############################################################################
diff --git a/codebuild/spec/buildspec_valgrind.yml b/codebuild/spec/buildspec_valgrind.yml
new file mode 100644
index 00000000000..01c9b21bb9b
--- /dev/null
+++ b/codebuild/spec/buildspec_valgrind.yml
@@ -0,0 +1,72 @@
+---
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You may not use
+# this file except in compliance with the License. A copy of the License is
+# located at
+#
+# http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied. See the License for the specific language governing permissions and
+# limitations under the License.
+version: 0.2
+
+batch:
+  build-list:
+    - identifier: gcc_awslc
+      env:
+        compute-type: BUILD_GENERAL1_LARGE
+        image: 024603541914.dkr.ecr.us-west-2.amazonaws.com/docker:ubuntu22codebuild
+        variables:
+          S2N_LIBCRYPTO: awslc
+          COMPILER: gcc
+    - identifier: gcc_openssl_3_0
+      env:
+        compute-type: BUILD_GENERAL1_LARGE
+        image: 024603541914.dkr.ecr.us-west-2.amazonaws.com/docker:ubuntu22codebuild
+        variables:
+          S2N_LIBCRYPTO: openssl-3.0
+          COMPILER: gcc
+    - identifier: gcc_openssl_1_1_1
+      env:
+        compute-type: BUILD_GENERAL1_LARGE
+        image: 024603541914.dkr.ecr.us-west-2.amazonaws.com/docker:ubuntu18codebuild
+        variables:
+          S2N_LIBCRYPTO: openssl-1.1.1
+          COMPILER: gcc
+    - identifier: gcc_openssl_1_0_2
+      env:
+        compute-type: BUILD_GENERAL1_LARGE
+        image: 024603541914.dkr.ecr.us-west-2.amazonaws.com/docker:ubuntu22codebuild
+        variables:
+          S2N_LIBCRYPTO: openssl-1.0.2
+          COMPILER: gcc
+
+phases:
+  pre_build:
+    commands:
+      - |
+        if [ -d "third-party-src" ]; then
+          cd third-party-src;
+        fi
+      - /usr/bin/$COMPILER --version
+  build:
+    on-failure: ABORT
+    commands:
+      - |
+        cmake . -Bbuild \
+          -DCMAKE_C_COMPILER=/usr/bin/$COMPILER \
+          -DCMAKE_PREFIX_PATH=/usr/local/$S2N_LIBCRYPTO \
+          -DCMAKE_BUILD_TYPE=RelWithDebInfo
+      - cmake --build ./build -- -j $(nproc)
+  post_build:
+    on-failure: ABORT
+    commands:
+      - |
+        S2N_VALGRIND=1 \
+        CTEST_PARALLEL_LEVEL=$(nproc) \
+        CTEST_OUTPUT_ON_FAILURE=1 \
+        cmake --build build/ --target test \
+          -- ARGS="--test-action memcheck"
diff --git a/tests/unit/s2n_alerts_protocol_test.c b/tests/unit/s2n_alerts_protocol_test.c
index 4e50f552835..fc62b7024b0 100644
--- a/tests/unit/s2n_alerts_protocol_test.c
+++ b/tests/unit/s2n_alerts_protocol_test.c
@@ -551,7 +551,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client, config));
 
-            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            struct s2n_test_io_pair io_pair = { 0 };
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client, server, &io_pair));
 
@@ -573,6 +573,8 @@ int main(int argc, char **argv)
                         S2N_ERR_CLOSED);
                 EXPECT_FALSE(s2n_connection_check_io_status(receiver, S2N_IO_READABLE));
             }
+            /* Close the other end of pipe */
+            EXPECT_SUCCESS(s2n_io_pair_close_one_end(&io_pair, 1 - mode));
         };
 
         /* Test: With partial read */
@@ -594,7 +596,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client, &partial_write_config_copy));
 
-            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            struct s2n_test_io_pair io_pair = { 0 };
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client, server, &io_pair));
 
@@ -629,6 +631,8 @@ int main(int argc, char **argv)
                 EXPECT_FAILURE_WITH_ERRNO(s2n_recv(receiver, data, sizeof(data), &blocked),
                         S2N_ERR_CLOSED);
             }
+            /* Close the other end of pipe */
+            EXPECT_SUCCESS(s2n_io_pair_close_one_end(&io_pair, 1 - mode));
         };
     };
 
diff --git a/tests/unit/s2n_certificate_test.c b/tests/unit/s2n_certificate_test.c
index bbe9fca0cd0..48797611486 100644
--- a/tests/unit/s2n_certificate_test.c
+++ b/tests/unit/s2n_certificate_test.c
@@ -698,7 +698,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(tls12_client_conn, "test_all_tls12"));
             EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(tls12_server_conn, "test_all_tls12"));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(tls12_client_conn, tls12_server_conn, &io_pair));
             EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(tls12_server_conn, tls12_client_conn));
@@ -719,7 +719,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(tls13_client_conn, "default_tls13"));
             EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(tls13_server_conn, "default_tls13"));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(tls13_client_conn, tls13_server_conn, &io_pair));
             EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(tls13_server_conn, tls13_client_conn));
diff --git a/tests/unit/s2n_client_hello_retry_test.c b/tests/unit/s2n_client_hello_retry_test.c
index 00ab2bcd5d8..c817ed54213 100644
--- a/tests/unit/s2n_client_hello_retry_test.c
+++ b/tests/unit/s2n_client_hello_retry_test.c
@@ -712,7 +712,7 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(client_conn);
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -741,7 +741,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -777,7 +777,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -810,7 +810,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -844,7 +844,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -886,7 +886,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -948,7 +948,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1001,7 +1001,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1067,7 +1067,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1118,7 +1118,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1185,7 +1185,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
             EXPECT_SUCCESS(s2n_set_server_name(client_conn, "localhost"));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1219,7 +1219,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
             EXPECT_SUCCESS(s2n_set_server_name(client_conn, "localhost"));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1253,7 +1253,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1301,7 +1301,7 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(client_conn);
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1425,7 +1425,7 @@ int main(int argc, char **argv)
             EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config_with_cb));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1509,7 +1509,7 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(client_conn);
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1553,7 +1553,7 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(client_conn);
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1606,7 +1606,7 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(client_conn);
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1643,7 +1643,7 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(client_conn);
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1709,7 +1709,7 @@ int main(int argc, char **argv)
         EXPECT_NOT_NULL(client_conn);
         EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-        struct s2n_test_io_pair io_pair = { 0 };
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1792,7 +1792,7 @@ int main(int argc, char **argv)
         EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
         EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-        struct s2n_test_io_pair io_pair = { 0 };
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1845,7 +1845,7 @@ int main(int argc, char **argv)
         EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
         EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-        struct s2n_test_io_pair io_pair = { 0 };
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1920,7 +1920,7 @@ int main(int argc, char **argv)
         EXPECT_NOT_NULL(client_conn);
         EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-        struct s2n_test_io_pair io_pair = { 0 };
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -1986,7 +1986,7 @@ int main(int argc, char **argv)
         EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
         EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
 
-        struct s2n_test_io_pair io_pair = { 0 };
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
diff --git a/tests/unit/s2n_client_psk_extension_test.c b/tests/unit/s2n_client_psk_extension_test.c
index 676b4401cc3..72555bfa847 100644
--- a/tests/unit/s2n_client_psk_extension_test.c
+++ b/tests/unit/s2n_client_psk_extension_test.c
@@ -500,7 +500,7 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(server_conn);
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
diff --git a/tests/unit/s2n_client_supported_versions_extension_test.c b/tests/unit/s2n_client_supported_versions_extension_test.c
index e76ff132c1a..f78a4ed8b7d 100644
--- a/tests/unit/s2n_client_supported_versions_extension_test.c
+++ b/tests/unit/s2n_client_supported_versions_extension_test.c
@@ -418,7 +418,7 @@ int main(int argc, char **argv)
         EXPECT_NOT_NULL(client_conn);
         EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config_with_cert));
 
-        struct s2n_test_io_pair io_pair = { 0 };
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
diff --git a/tests/unit/s2n_config_test.c b/tests/unit/s2n_config_test.c
index 998754458a4..e43930bb188 100644
--- a/tests/unit/s2n_config_test.c
+++ b/tests/unit/s2n_config_test.c
@@ -910,7 +910,7 @@ int main(int argc, char **argv)
                 EXPECT_SUCCESS(s2n_connection_set_config(client_conn, client_config));
                 EXPECT_SUCCESS(s2n_set_server_name(client_conn, "localhost"));
 
-                struct s2n_test_io_pair io_pair = { 0 };
+                DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
                 EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
                 EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -945,7 +945,7 @@ int main(int argc, char **argv)
                 EXPECT_SUCCESS(s2n_connection_set_config(client_conn, client_config));
                 EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
 
-                struct s2n_test_io_pair io_pair = { 0 };
+                DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
                 EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
                 EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
diff --git a/tests/unit/s2n_crypto_test.c b/tests/unit/s2n_crypto_test.c
index 744f25c4b99..e6a8fc8f768 100644
--- a/tests/unit/s2n_crypto_test.c
+++ b/tests/unit/s2n_crypto_test.c
@@ -142,7 +142,7 @@ int main()
             /* Set server master secret to known value to ensure overridden later */
             memset(server->secrets.version.tls12.master_secret, 1, S2N_TLS_SECRET_LEN);
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client, server, &io_pair));
             EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server, client));
diff --git a/tests/unit/s2n_drbg_test.c b/tests/unit/s2n_drbg_test.c
index 4595ff79b6f..4b4222cfbfc 100644
--- a/tests/unit/s2n_drbg_test.c
+++ b/tests/unit/s2n_drbg_test.c
@@ -451,6 +451,8 @@ int main(int argc, char **argv)
     EXPECT_SUCCESS(s2n_stuffer_free(&nist_aes256_reference_entropy));
 
     EXPECT_SUCCESS(s2n_config_free(config));
+    /* Clean up with previously set functions */
+    POSIX_GUARD_RESULT(s2n_rand_cleanup());
 
     END_TEST();
 }
diff --git a/tests/unit/s2n_early_data_io_api_test.c b/tests/unit/s2n_early_data_io_api_test.c
index 38b56330e51..ba599a5b674 100644
--- a/tests/unit/s2n_early_data_io_api_test.c
+++ b/tests/unit/s2n_early_data_io_api_test.c
@@ -28,7 +28,8 @@
     EXPECT_EQUAL((blocked), (expected_blocked));                         \
     EXPECT_EQUAL(s2n_conn_get_current_message_type(conn), (expected_msg))
 
-static S2N_RESULT s2n_test_client_and_server_new(struct s2n_connection **client_conn, struct s2n_connection **server_conn)
+static S2N_RESULT s2n_test_client_and_server_new(struct s2n_connection **client_conn, struct s2n_connection **server_conn,
+        struct s2n_test_io_pair *io_pair)
 {
     *client_conn = s2n_connection_new(S2N_CLIENT);
     EXPECT_NOT_NULL(*client_conn);
@@ -39,9 +40,8 @@ static S2N_RESULT s2n_test_client_and_server_new(struct s2n_connection **client_
     EXPECT_SUCCESS(s2n_connection_set_blinding(*server_conn, S2N_SELF_SERVICE_BLINDING));
     EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(*server_conn, "default_tls13"));
 
-    struct s2n_test_io_pair io_pair = { 0 };
-    EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
-    EXPECT_SUCCESS(s2n_connections_set_io_pair(*client_conn, *server_conn, &io_pair));
+    EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(io_pair));
+    EXPECT_SUCCESS(s2n_connections_set_io_pair(*client_conn, *server_conn, io_pair));
 
     return S2N_RESULT_OK;
 }
@@ -247,7 +247,8 @@ int main(int argc, char **argv)
         /* Propagate errors from s2n_recv */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
 
@@ -276,7 +277,8 @@ int main(int argc, char **argv)
         /* Send zero-length early data */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -308,7 +310,8 @@ int main(int argc, char **argv)
         /* Send early data once */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -342,7 +345,8 @@ int main(int argc, char **argv)
         /* Receive early data too large for buffer */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -393,7 +397,8 @@ int main(int argc, char **argv)
         /* Send multiple early data messages */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -432,7 +437,8 @@ int main(int argc, char **argv)
         /* Receive and combine multiple early data records */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -474,7 +480,8 @@ int main(int argc, char **argv)
         /* Early data not requested */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk_with_wrong_early_data));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -509,7 +516,8 @@ int main(int argc, char **argv)
         /* Early data rejected */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk_with_wrong_early_data));
diff --git a/tests/unit/s2n_early_data_io_test.c b/tests/unit/s2n_early_data_io_test.c
index 75c133cc033..a388126f7e5 100644
--- a/tests/unit/s2n_early_data_io_test.c
+++ b/tests/unit/s2n_early_data_io_test.c
@@ -25,7 +25,8 @@
     EXPECT_EQUAL(s2n_recv(conn, data_buffer, data_buffer_size, blocked), data_len);           \
     EXPECT_BYTEARRAY_EQUAL(data_buffer, data, data_len)
 
-static S2N_RESULT s2n_test_client_and_server_new(struct s2n_connection **client_conn, struct s2n_connection **server_conn)
+static S2N_RESULT s2n_test_client_and_server_new(struct s2n_connection **client_conn, struct s2n_connection **server_conn,
+        struct s2n_test_io_pair *io_pair)
 {
     *client_conn = s2n_connection_new(S2N_CLIENT);
     EXPECT_NOT_NULL(*client_conn);
@@ -36,9 +37,8 @@ static S2N_RESULT s2n_test_client_and_server_new(struct s2n_connection **client_
     EXPECT_SUCCESS(s2n_connection_set_blinding(*server_conn, S2N_SELF_SERVICE_BLINDING));
     EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(*server_conn, "default_tls13"));
 
-    struct s2n_test_io_pair io_pair = { 0 };
-    EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
-    EXPECT_SUCCESS(s2n_connections_set_io_pair(*client_conn, *server_conn, &io_pair));
+    EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(io_pair));
+    EXPECT_SUCCESS(s2n_connections_set_io_pair(*client_conn, *server_conn, io_pair));
 
     return S2N_RESULT_OK;
 }
@@ -88,7 +88,8 @@ int main(int argc, char **argv)
         /* Early data not supported by server */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -115,7 +116,8 @@ int main(int argc, char **argv)
         /* Early data not supported by client */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -142,7 +144,8 @@ int main(int argc, char **argv)
         /* Server does not support TLS1.3 */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_set_early_data_expected(client_conn));
@@ -166,7 +169,8 @@ int main(int argc, char **argv)
         /* Early data accepted */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -212,7 +216,8 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(config);
 
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
             EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
@@ -255,7 +260,8 @@ int main(int argc, char **argv)
         /* Early data rejected */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk_without_early_data));
@@ -289,7 +295,8 @@ int main(int argc, char **argv)
             EXPECT_NOT_NULL(config);
 
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
             EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
@@ -327,7 +334,8 @@ int main(int argc, char **argv)
         /* Early data rejected and ignored */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk_to_reject));
@@ -364,7 +372,8 @@ int main(int argc, char **argv)
         /* Early data rejected, but too much early data received */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk_to_reject));
@@ -403,7 +412,8 @@ int main(int argc, char **argv)
         /* Early data rejected due to HRR */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -494,7 +504,8 @@ int main(int argc, char **argv)
         /* PSK rejected altogether */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config_with_cert));
             EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config_with_cert));
@@ -526,7 +537,8 @@ int main(int argc, char **argv)
         /* End early data after the server accepts the early data request */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -589,7 +601,8 @@ int main(int argc, char **argv)
         /* End early data before the server accepts the early data request. */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -626,7 +639,8 @@ int main(int argc, char **argv)
         {
             DEFER_CLEANUP(struct s2n_connection *client_conn = NULL, s2n_connection_ptr_free);
             DEFER_CLEANUP(struct s2n_connection *server_conn = NULL, s2n_connection_ptr_free);
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -675,7 +689,8 @@ int main(int argc, char **argv)
         /* s2n_recv can read early data sent with s2n_send */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -742,7 +757,8 @@ int main(int argc, char **argv)
         /* s2n_recv fails if it encounters a handshake message instead of early data. */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
@@ -774,7 +790,8 @@ int main(int argc, char **argv)
         /* s2n_recv fails on too much early data */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_test_client_and_server_new(&client_conn, &server_conn, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
diff --git a/tests/unit/s2n_examples_test.c b/tests/unit/s2n_examples_test.c
index 9e06ee27ea7..7c0edcd68ad 100644
--- a/tests/unit/s2n_examples_test.c
+++ b/tests/unit/s2n_examples_test.c
@@ -250,6 +250,7 @@ static S2N_RESULT s2n_run_self_talk_test(s2n_test_scenario scenario_fn)
         EXPECT_SUCCESS(s2n_cert_chain_and_key_free(chain_and_key));
         EXPECT_SUCCESS(s2n_config_free(config));
         EXPECT_SUCCESS(s2n_free(&input));
+        EXPECT_SUCCESS(s2n_io_pair_close_one_end(&io_pair, S2N_CLIENT));
 
         exit(EXIT_SUCCESS);
     }
@@ -273,6 +274,7 @@ static S2N_RESULT s2n_run_self_talk_test(s2n_test_scenario scenario_fn)
         EXPECT_SUCCESS(s2n_cert_chain_and_key_free(chain_and_key));
         EXPECT_SUCCESS(s2n_config_free(config));
         EXPECT_SUCCESS(s2n_free(&input));
+        EXPECT_SUCCESS(s2n_io_pair_close_one_end(&io_pair, S2N_SERVER));
 
         exit(EXIT_SUCCESS);
     }
diff --git a/tests/unit/s2n_extension_type_test.c b/tests/unit/s2n_extension_type_test.c
index 2b5ea4e9ddf..97b60a97c34 100644
--- a/tests/unit/s2n_extension_type_test.c
+++ b/tests/unit/s2n_extension_type_test.c
@@ -487,7 +487,7 @@ int main()
                 EXPECT_NOT_NULL(server_conn);
                 EXPECT_SUCCESS(s2n_connection_set_config(server_conn, test_all_config));
 
-                struct s2n_test_io_pair io_pair = { 0 };
+                DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
                 EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
                 EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -515,7 +515,7 @@ int main()
                 EXPECT_NOT_NULL(server_conn);
                 EXPECT_SUCCESS(s2n_connection_set_config(server_conn, test_all_config));
 
-                struct s2n_test_io_pair io_pair = { 0 };
+                DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
                 EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
                 EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
@@ -544,7 +544,7 @@ int main()
                 EXPECT_SUCCESS(s2n_connection_set_config(server_conn, test_all_config));
                 EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(server_conn, "test_all_tls12"));
 
-                struct s2n_test_io_pair io_pair = { 0 };
+                DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
                 EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
                 EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
diff --git a/tests/unit/s2n_fork_generation_number_test.c b/tests/unit/s2n_fork_generation_number_test.c
index 6ccf9e9274f..5b99dc15577 100644
--- a/tests/unit/s2n_fork_generation_number_test.c
+++ b/tests/unit/s2n_fork_generation_number_test.c
@@ -30,6 +30,7 @@
 
 #include "s2n_test.h"
 #include "utils/s2n_fork_detection.h"
+#include "utils/s2n_random.h"
 
 #define NUMBER_OF_FGN_TEST_CASES   4
 #define MAX_NUMBER_OF_TEST_THREADS 2
@@ -189,6 +190,9 @@ static int s2n_unit_test_clone_child_process(void *parent_process_fgn)
     /* Verify in threads */
     EXPECT_EQUAL(s2n_unit_test_thread(return_fork_generation_number), S2N_SUCCESS);
 
+    /* Clean up urandom of the child process */
+    POSIX_GUARD_RESULT(s2n_rand_cleanup());
+
     /* This translates to the exit code for this child process */
     return EXIT_SUCCESS;
 }
diff --git a/tests/unit/s2n_handshake_partial_test.c b/tests/unit/s2n_handshake_partial_test.c
index 0ec829635d8..f1ed4a2b847 100644
--- a/tests/unit/s2n_handshake_partial_test.c
+++ b/tests/unit/s2n_handshake_partial_test.c
@@ -20,7 +20,7 @@
 #include "tls/s2n_tls.h"
 
 static S2N_RESULT s2n_get_test_client_and_server(struct s2n_connection **client_conn, struct s2n_connection **server_conn,
-        struct s2n_config *config)
+        struct s2n_config *config, struct s2n_test_io_pair *io_pair)
 {
     *client_conn = s2n_connection_new(S2N_CLIENT);
     RESULT_ENSURE_REF(*client_conn);
@@ -32,9 +32,8 @@ static S2N_RESULT s2n_get_test_client_and_server(struct s2n_connection **client_
     RESULT_GUARD_POSIX(s2n_connection_set_config(*client_conn, config));
     RESULT_GUARD_POSIX(s2n_connection_set_config(*server_conn, config));
 
-    struct s2n_test_io_pair io_pair = { 0 };
-    RESULT_GUARD_POSIX(s2n_io_pair_init_non_blocking(&io_pair));
-    RESULT_GUARD_POSIX(s2n_connections_set_io_pair(*client_conn, *server_conn, &io_pair));
+    RESULT_GUARD_POSIX(s2n_io_pair_init_non_blocking(io_pair));
+    RESULT_GUARD_POSIX(s2n_connections_set_io_pair(*client_conn, *server_conn, io_pair));
 
     return S2N_RESULT_OK;
 }
@@ -75,7 +74,8 @@ int main()
         /* If message is never encountered, complete the handshake */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config, &io_pair));
 
             EXPECT_OK(s2n_negotiate_test_server_and_client_until_message(server_conn, client_conn,
                     SERVER_KEY));
@@ -89,7 +89,8 @@ int main()
         /* Can stop on a given message */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config, &io_pair));
 
             EXPECT_OK(s2n_negotiate_test_server_and_client_until_message(server_conn, client_conn,
                     SERVER_CERT_VERIFY));
@@ -103,7 +104,8 @@ int main()
         /* Can be called repeatedly */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config, &io_pair));
 
             EXPECT_OK(s2n_negotiate_test_server_and_client_until_message(server_conn, client_conn,
                     CLIENT_HELLO));
@@ -142,7 +144,8 @@ int main()
         /* Can continue as normal after stopping */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config, &io_pair));
 
             EXPECT_OK(s2n_negotiate_test_server_and_client_until_message(server_conn, client_conn,
                     CLIENT_FINISHED));
@@ -161,7 +164,8 @@ int main()
          * (This is the non-test use case for this feature) */
         {
             struct s2n_connection *client_conn = NULL, *server_conn = NULL;
-            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config));
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+            EXPECT_OK(s2n_get_test_client_and_server(&client_conn, &server_conn, config, &io_pair));
 
             EXPECT_SUCCESS(s2n_connection_append_psk(client_conn, test_psk));
             EXPECT_SUCCESS(s2n_connection_append_psk(server_conn, test_psk));
diff --git a/tests/unit/s2n_io_test.c b/tests/unit/s2n_io_test.c
index c06782f9308..b75254b2a07 100644
--- a/tests/unit/s2n_io_test.c
+++ b/tests/unit/s2n_io_test.c
@@ -102,6 +102,8 @@ int main(int argc, char **argv)
                         s2n_test_real_interrupt(io_pair.client, n_times, &counter));
                 EXPECT_EQUAL(result, S2N_TEST_SUCCESS);
                 EXPECT_EQUAL(counter, n_times);
+                /* Child process exit don't close io_pair properly, so manually close it*/
+                EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
                 exit(0);
             }
 
diff --git a/tests/unit/s2n_key_update_threads_test.c b/tests/unit/s2n_key_update_threads_test.c
index 364e26edf67..418fbd4f152 100644
--- a/tests/unit/s2n_key_update_threads_test.c
+++ b/tests/unit/s2n_key_update_threads_test.c
@@ -208,6 +208,7 @@ static S2N_RESULT s2n_run_self_talk_test(s2n_test_scenario scenario_fn)
         EXPECT_SUCCESS(s2n_connection_free(client));
         EXPECT_SUCCESS(s2n_cert_chain_and_key_free(chain_and_key));
         EXPECT_SUCCESS(s2n_config_free(config));
+        EXPECT_SUCCESS(s2n_io_pair_close_one_end(&io_pair, S2N_CLIENT));
 
         exit(EXIT_SUCCESS);
     }
@@ -231,6 +232,7 @@ static S2N_RESULT s2n_run_self_talk_test(s2n_test_scenario scenario_fn)
         EXPECT_SUCCESS(s2n_connection_free(server));
         EXPECT_SUCCESS(s2n_cert_chain_and_key_free(chain_and_key));
         EXPECT_SUCCESS(s2n_config_free(config));
+        EXPECT_SUCCESS(s2n_io_pair_close_one_end(&io_pair, S2N_SERVER));
 
         exit(EXIT_SUCCESS);
     }
diff --git a/tests/unit/s2n_ktls_io_sendfile_test.c b/tests/unit/s2n_ktls_io_sendfile_test.c
index 718d802fc5d..3d13cfd7730 100644
--- a/tests/unit/s2n_ktls_io_sendfile_test.c
+++ b/tests/unit/s2n_ktls_io_sendfile_test.c
@@ -133,7 +133,7 @@ int main(int argc, char **argv)
         EXPECT_NOT_NULL(conn);
         conn->ktls_send_enabled = true;
 
-        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
+        struct s2n_test_io_pair io_pair = { 0 };
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         int write_fd = io_pair.server;
         int read_fd = io_pair.client;
@@ -149,6 +149,7 @@ int main(int argc, char **argv)
         EXPECT_FAILURE_WITH_ERRNO(ret, S2N_ERR_IO);
         EXPECT_EQUAL(bytes_written, 0);
         EXPECT_EQUAL(blocked, S2N_BLOCKED_ON_WRITE);
+        close(write_fd);
     };
 
     /* Test: send blocks */
diff --git a/tests/unit/s2n_mem_usage_test.c b/tests/unit/s2n_mem_usage_test.c
index 2eeeb90ecdb..e2dc88ddf88 100644
--- a/tests/unit/s2n_mem_usage_test.c
+++ b/tests/unit/s2n_mem_usage_test.c
@@ -155,7 +155,7 @@ int main(int argc, char **argv)
     BEGIN_TEST();
     EXPECT_SUCCESS(s2n_disable_tls13_in_test());
 
-    struct s2n_test_io_pair io_pair;
+    DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
     EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
 
     /* Skip the test when running under valgrind or address sanitizer, as those tools
diff --git a/tests/unit/s2n_override_openssl_random_test.c b/tests/unit/s2n_override_openssl_random_test.c
index 765d806b525..b82043abf89 100644
--- a/tests/unit/s2n_override_openssl_random_test.c
+++ b/tests/unit/s2n_override_openssl_random_test.c
@@ -131,6 +131,8 @@ int main(int argc, char **argv)
     EXPECT_SUCCESS(s2n_stuffer_free(&dhparams_in));
     EXPECT_SUCCESS(s2n_stuffer_free(&test_entropy));
     free(dhparams_pem);
+    /* Clean up with previously set functions */
+    POSIX_GUARD_RESULT(s2n_rand_cleanup());
 
     END_TEST();
 }
diff --git a/tests/unit/s2n_random_test.c b/tests/unit/s2n_random_test.c
index b2b5ecdbd63..2132854cfb2 100644
--- a/tests/unit/s2n_random_test.c
+++ b/tests/unit/s2n_random_test.c
@@ -839,10 +839,9 @@ static int s2n_random_invalid_urandom_fd_cb(struct random_test_case *test_case)
         EXPECT_OK(s2n_rand_set_urandom_for_test());
 
         EXPECT_TRUE(dev_urandom->fd > STDERR_FILENO);
-        if (test == 0) {
-            /* Close the file descriptor. */
-            EXPECT_EQUAL(close(dev_urandom->fd), 0);
-        } else {
+        /* Close the file descriptor. */
+        EXPECT_EQUAL(close(dev_urandom->fd), 0);
+        if (test != 0) {
             /* Make the file descriptor invalid by pointing it to STDERR. */
             dev_urandom->fd = STDERR_FILENO;
         }
diff --git a/tests/unit/s2n_recv_test.c b/tests/unit/s2n_recv_test.c
index acb6e37ee12..93bd93aad58 100644
--- a/tests/unit/s2n_recv_test.c
+++ b/tests/unit/s2n_recv_test.c
@@ -88,7 +88,7 @@ int main(int argc, char **argv)
                     s2n_connection_ptr_free);
             EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
             EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
@@ -234,7 +234,7 @@ int main(int argc, char **argv)
                     s2n_connection_ptr_free);
             EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
 
-            struct s2n_test_io_pair io_pair = { 0 };
+            DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
             EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
             EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
             EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
@@ -280,7 +280,7 @@ int main(int argc, char **argv)
                 s2n_connection_ptr_free);
         EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
 
-        struct s2n_test_io_pair io_pair = { 0 };
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
         EXPECT_SUCCESS(s2n_negotiate_test_server_and_client(server_conn, client_conn));
diff --git a/tests/unit/s2n_release_non_empty_buffers_test.c b/tests/unit/s2n_release_non_empty_buffers_test.c
index 7888583e925..7f40115e673 100644
--- a/tests/unit/s2n_release_non_empty_buffers_test.c
+++ b/tests/unit/s2n_release_non_empty_buffers_test.c
@@ -59,6 +59,7 @@ int mock_client(struct s2n_test_io_pair *io_pair)
     s2n_connection_free(conn);
     s2n_config_free(client_config);
     s2n_cleanup();
+    EXPECT_SUCCESS(s2n_io_pair_close_one_end(io_pair, S2N_CLIENT));
 
     exit(0);
 }
@@ -82,7 +83,7 @@ int main(int argc, char **argv)
     EXPECT_SUCCESS(s2n_disable_tls13_in_test());
 
     /* Create a pipe */
-    struct s2n_test_io_pair io_pair;
+    DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
     EXPECT_SUCCESS(s2n_io_pair_init(&io_pair));
 
     /* Create a child process */
@@ -196,6 +197,7 @@ int main(int argc, char **argv)
     free(private_key_pem);
 
     s2n_cleanup();
+    EXPECT_SUCCESS(s2n_io_pair_close_one_end(&io_pair, S2N_SERVER));
 
     END_TEST();
 
diff --git a/tests/unit/s2n_self_talk_broken_pipe_test.c b/tests/unit/s2n_self_talk_broken_pipe_test.c
index 2303b9230da..8b3508a3f79 100644
--- a/tests/unit/s2n_self_talk_broken_pipe_test.c
+++ b/tests/unit/s2n_self_talk_broken_pipe_test.c
@@ -82,6 +82,7 @@ void mock_client(struct s2n_test_io_pair *io_pair)
     sleep(1);
 
     s2n_io_pair_shutdown_one_end(io_pair, S2N_CLIENT, SHUT_WR);
+    s2n_io_pair_close_one_end(io_pair, S2N_CLIENT);
 
     exit(0);
 }
@@ -102,7 +103,7 @@ int main(int argc, char **argv)
         struct s2n_cert_chain_and_key *chain_and_keys[SUPPORTED_CERTIFICATE_FORMATS];
 
         /* Create a pipe */
-        struct s2n_test_io_pair io_pair;
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init(&io_pair));
 
         /* Create a child process */
diff --git a/tests/unit/s2n_self_talk_io_mem_test.c b/tests/unit/s2n_self_talk_io_mem_test.c
index f28a1d1f8fc..058cb901421 100644
--- a/tests/unit/s2n_self_talk_io_mem_test.c
+++ b/tests/unit/s2n_self_talk_io_mem_test.c
@@ -54,7 +54,7 @@ int main(int argc, char **argv)
         EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
 
         /* Create nonblocking pipes */
-        struct s2n_test_io_pair io_pair;
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(client_conn, &io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(server_conn, &io_pair));
@@ -89,7 +89,7 @@ int main(int argc, char **argv)
         EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
 
         /* Create nonblocking pipes */
-        struct s2n_test_io_pair io_pair;
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(client_conn, &io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(server_conn, &io_pair));
@@ -143,7 +143,7 @@ int main(int argc, char **argv)
         EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config_for_mfl));
 
         /* Create nonblocking pipes */
-        struct s2n_test_io_pair io_pair;
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(client_conn, &io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(server_conn, &io_pair));
@@ -190,7 +190,7 @@ int main(int argc, char **argv)
         EXPECT_EQUAL(server_conn->out.blob.size, 0);
 
         /* Create nonblocking pipes */
-        struct s2n_test_io_pair io_pair;
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
         EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(client_conn, &io_pair));
         EXPECT_SUCCESS(s2n_connection_set_io_pair(server_conn, &io_pair));
diff --git a/tests/unit/s2n_self_talk_session_id_test.c b/tests/unit/s2n_self_talk_session_id_test.c
index f111e77cd33..933ccc16a20 100644
--- a/tests/unit/s2n_self_talk_session_id_test.c
+++ b/tests/unit/s2n_self_talk_session_id_test.c
@@ -578,6 +578,7 @@ int main(int argc, char **argv)
 
         EXPECT_SUCCESS(s2n_connection_free(client_conn));
         EXPECT_SUCCESS(s2n_connection_free(server_conn));
+        EXPECT_SUCCESS(s2n_io_pair_close(&io_pair));
     };
 
     /**
diff --git a/tests/unit/s2n_testlib_test.c b/tests/unit/s2n_testlib_test.c
index f5f7b8b9df0..127c4976072 100644
--- a/tests/unit/s2n_testlib_test.c
+++ b/tests/unit/s2n_testlib_test.c
@@ -33,7 +33,7 @@ int main(int argc, char **argv)
         EXPECT_NOT_NULL(server_conn = s2n_connection_new(S2N_SERVER));
 
         /* Create nonblocking pipes */
-        struct s2n_test_io_pair io_pair;
+        DEFER_CLEANUP(struct s2n_test_io_pair io_pair, s2n_io_pair_close);
         POSIX_GUARD(s2n_io_pair_init_non_blocking(&io_pair));
         POSIX_GUARD(s2n_connection_set_io_pair(server_conn, &io_pair));
 
diff --git a/tests/unit/s2n_tls13_cert_verify_test.c b/tests/unit/s2n_tls13_cert_verify_test.c
index 7a6e781be1a..a3d362440a1 100644
--- a/tests/unit/s2n_tls13_cert_verify_test.c
+++ b/tests/unit/s2n_tls13_cert_verify_test.c
@@ -307,7 +307,7 @@ int main(int argc, char **argv)
                 client_policy.signature_preferences = &test_sig_preferences;
                 client_conn->security_policy_override = &client_policy;
 
-                struct s2n_test_io_pair io_pair = { 0 };
+                DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
                 EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
                 EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
 
diff --git a/tests/unit/valgrind.suppressions b/tests/unit/valgrind.suppressions
index 3662410a9bf..e0f90fd05cb 100644
--- a/tests/unit/valgrind.suppressions
+++ b/tests/unit/valgrind.suppressions
@@ -1,13 +1,48 @@
-# It looks like valgrind may generate false positives on pthreads: https://stackoverflow.com/a/13132968
+# Valgrind may generate false positives on pthreads: https://stackoverflow.com/a/13132968
+# Without these suppressions, the following tests will fail:
+# s2n_examples_test, s2n_fork_generation_number_test, s2n_init_test, s2n_key_update_threads_test, and s2n_random_test.
 {
-   pthred_false_positive
+   pthread_false_positive
    Memcheck:Leak
    match-leak-kinds: possible
    fun:calloc
+   ...
    fun:allocate_dtv
    fun:_dl_allocate_tls
    fun:allocate_stack
-   fun:pthread_create@@GLIBC_2.2.5
+   fun:pthread_create@@*
+   ...
+   fun:main
+}
+
+# This memory leak is believed to be caused by backtrace() loading libgcc dynamically.
+# See https://man7.org/linux/man-pages/man3/backtrace_symbols_fd.3.html
+# We were unable to find any relevant bug reports. However, testing showed that the memory
+# leak didn't scale with the number of calls to backtrace(), both supporting this theory and
+# limiting the potential impact of the leak.
+{
+   stacktrace_suppression
+   Memcheck:Leak
+   match-leak-kinds: possible
+   fun:malloc
+   fun:malloc
+   fun:_dlfo_mappings_segment_allocate
+   fun:_dl_find_object_update_1
+   fun:_dl_find_object_update
+   fun:dl_open_worker_begin
+   fun:_dl_catch_exception
+   fun:dl_open_worker
+   fun:_dl_catch_exception
+   fun:_dl_open
+   fun:do_dlopen
+   fun:_dl_catch_exception
+   fun:_dl_catch_error
+   fun:dlerror_run
+   fun:__libc_dlopen_mode
+   fun:__libc_unwind_link_get
+   ...
+   fun:backtrace
+   ...
    fun:main
 }