diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index f5223fb..6a39800 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -2169,8 +2169,8 @@
             }
 
             /* get size of the buffer needed */
-            mbedtls_ssl_session_save(mbedtls_ssl_get_session_pointer(&ssl),
-                                     NULL, 0, &session_data_len);
+            (void) mbedtls_ssl_session_save(mbedtls_ssl_get_session_pointer(&ssl),
+                                            NULL, 0, &session_data_len);
             session_data = mbedtls_calloc(1, session_data_len);
             if (session_data == NULL) {
                 mbedtls_printf(" failed\n  ! alloc %u bytes for session data\n",
diff --git a/tests/include/test/macros.h b/tests/include/test/macros.h
index f942889..d67e487 100644
--- a/tests/include/test/macros.h
+++ b/tests/include/test/macros.h
@@ -153,6 +153,38 @@
         }                                                   \
     } while (0)
 
+/** Allocate memory dynamically and fail the test case if this fails.
+ * The allocated memory will be filled with zeros.
+ *
+ * You must set \p pointer to \c NULL before calling this macro and
+ * put `mbedtls_free(pointer)` in the test's cleanup code.
+ *
+ * If \p item_count is zero, the resulting \p pointer will not be \c NULL.
+ *
+ * This macro expands to an instruction, not an expression.
+ * It may jump to the \c exit label.
+ *
+ * \param pointer    An lvalue where the address of the allocated buffer
+ *                   will be stored.
+ *                   This expression may be evaluated multiple times.
+ * \param item_count Number of elements to allocate.
+ *                   This expression may be evaluated multiple times.
+ *
+ * Note: if passing size 0, mbedtls_calloc may return NULL. In this case,
+ * we reattempt to allocate with the smallest possible buffer to assure a
+ * non-NULL pointer.
+ */
+#define TEST_CALLOC_NONNULL(pointer, item_count)            \
+    do {                                                    \
+        TEST_ASSERT((pointer) == NULL);                     \
+        (pointer) = mbedtls_calloc(sizeof(*(pointer)),      \
+                                   (item_count));           \
+        if (((pointer) == NULL) && ((item_count) == 0)) {   \
+            (pointer) = mbedtls_calloc(1, 1);               \
+        }                                                   \
+        TEST_ASSERT((pointer) != NULL);                     \
+    } while (0)
+
 /* For backwards compatibility */
 #define ASSERT_ALLOC(pointer, item_count) TEST_CALLOC(pointer, item_count)
 
diff --git a/tests/suites/test_suite_ctr_drbg.function b/tests/suites/test_suite_ctr_drbg.function
index 4c6ee6f..a4627de 100644
--- a/tests/suites/test_suite_ctr_drbg.function
+++ b/tests/suites/test_suite_ctr_drbg.function
@@ -31,15 +31,13 @@
                                        data_t *result)
 {
     mbedtls_ctr_drbg_context ctx;
+    mbedtls_ctr_drbg_init(&ctx);
     unsigned char buf[64];
 
     size_t entropy_chunk_len = (size_t) entropy_len_arg;
-
     TEST_ASSERT(entropy_chunk_len <= sizeof(buf));
 
     test_offset_idx = 0;
-    mbedtls_ctr_drbg_init(&ctx);
-
     test_max_idx = entropy->len;
 
     /* CTR_DRBG_Instantiate(entropy[:entropy->len], nonce, perso, <ignored>)
diff --git a/tests/suites/test_suite_entropy.function b/tests/suites/test_suite_entropy.function
index 5d8487c..9b1df8f 100644
--- a/tests/suites/test_suite_entropy.function
+++ b/tests/suites/test_suite_entropy.function
@@ -102,6 +102,7 @@
 
     if (fwrite(buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f) !=
         MBEDTLS_ENTROPY_BLOCK_SIZE) {
+        fclose(f);
         return -1;
     }
 
@@ -124,6 +125,7 @@
 
     if (fread(buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f) !=
         MBEDTLS_ENTROPY_BLOCK_SIZE) {
+        fclose(f);
         return -1;
     }
 
diff --git a/tests/suites/test_suite_pkwrite.function b/tests/suites/test_suite_pkwrite.function
index d1f7813..97fd92a 100644
--- a/tests/suites/test_suite_pkwrite.function
+++ b/tests/suites/test_suite_pkwrite.function
@@ -31,13 +31,13 @@
 static void pk_write_check_common(char *key_file, int is_public_key, int is_der)
 {
     mbedtls_pk_context key;
+    mbedtls_pk_init(&key);
     unsigned char *buf = NULL;
     unsigned char *check_buf = NULL;
     unsigned char *start_buf;
     size_t buf_len, check_buf_len;
     int ret;
 
-    mbedtls_pk_init(&key);
     USE_PSA_INIT();
 
     /* Note: if mbedtls_pk_load_file() successfully reads the file, then
diff --git a/tests/suites/test_suite_psa_crypto_se_driver_hal.function b/tests/suites/test_suite_psa_crypto_se_driver_hal.function
index 15232a4..ff0ccdd 100644
--- a/tests/suites/test_suite_psa_crypto_se_driver_hal.function
+++ b/tests/suites/test_suite_psa_crypto_se_driver_hal.function
@@ -1290,7 +1290,7 @@
     mbedtls_svc_key_id_t returned_id;
     mbedtls_svc_key_id_t sw_key = MBEDTLS_SVC_KEY_ID_INIT;
     psa_key_attributes_t sw_attributes = PSA_KEY_ATTRIBUTES_INIT;
-    psa_key_attributes_t drv_attributes;
+    psa_key_attributes_t drv_attributes = PSA_KEY_ATTRIBUTES_INIT;
     uint8_t signature[PSA_SIGNATURE_MAX_SIZE];
     size_t signature_length;
 
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 0a35aa9..2eb1c4e 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -19,6 +19,7 @@
 {
     enum { MSGLEN = 10 };
     mbedtls_test_ssl_buffer buf;
+    mbedtls_test_ssl_buffer_init(&buf);
     unsigned char input[MSGLEN];
     unsigned char output[MSGLEN];
 
@@ -38,8 +39,6 @@
 
     /* Make sure calling put and get on a buffer that hasn't been set up results
      * in error. */
-    mbedtls_test_ssl_buffer_init(&buf);
-
     TEST_ASSERT(mbedtls_test_ssl_buffer_put(&buf, input, sizeof(input))
                 == -1);
     TEST_ASSERT(mbedtls_test_ssl_buffer_get(&buf, output, sizeof(output))
@@ -1186,7 +1185,7 @@
                                                   (size_t) cid0_len,
                                                   (size_t) cid1_len) == 0);
 
-    TEST_ASSERT((buf = mbedtls_calloc(1, buflen)) != NULL);
+    TEST_CALLOC(buf, buflen);
 
     while (num_records-- > 0) {
         mbedtls_ssl_transform *t_dec, *t_enc;
@@ -1336,7 +1335,7 @@
                                                   (size_t) cid0_len,
                                                   (size_t) cid1_len) == 0);
 
-    TEST_ASSERT((buf = mbedtls_calloc(1, buflen)) != NULL);
+    TEST_CALLOC(buf, buflen);
 
     for (mode = 1; mode <= 3; mode++) {
         seen_success = 0;
@@ -1637,7 +1636,7 @@
     /* Serialize it */
     TEST_ASSERT(mbedtls_ssl_session_save(&original, NULL, 0, &len)
                 == MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL);
-    TEST_ASSERT((buf = mbedtls_calloc(1, len)) != NULL);
+    TEST_CALLOC(buf, len);
     TEST_ASSERT(mbedtls_ssl_session_save(&original, buf, len, &len)
                 == 0);
 
@@ -1792,7 +1791,8 @@
     for (bad_len = 1; bad_len < good_len; bad_len++) {
         /* Allocate exact size so that asan/valgrind can detect any overwrite */
         mbedtls_free(buf);
-        TEST_ASSERT((buf = mbedtls_calloc(1, bad_len)) != NULL);
+        buf = NULL;
+        TEST_CALLOC(buf, bad_len);
         TEST_ASSERT(mbedtls_ssl_session_save(&session, buf, bad_len,
                                              &test_len)
                     == MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL);
@@ -1824,7 +1824,7 @@
                     &session, ticket_len, crt_file) == 0);
     TEST_ASSERT(mbedtls_ssl_session_save(&session, NULL, 0, &good_len)
                 == MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL);
-    TEST_ASSERT((good_buf = mbedtls_calloc(1, good_len)) != NULL);
+    TEST_CALLOC(good_buf, good_len);
     TEST_ASSERT(mbedtls_ssl_session_save(&session, good_buf, good_len,
                                          &good_len) == 0);
     mbedtls_ssl_session_free(&session);
@@ -1833,8 +1833,8 @@
     for (bad_len = 0; bad_len < good_len; bad_len++) {
         /* Allocate exact size so that asan/valgrind can detect any overread */
         mbedtls_free(bad_buf);
-        bad_buf = mbedtls_calloc(1, bad_len ? bad_len : 1);
-        TEST_ASSERT(bad_buf != NULL);
+        bad_buf = NULL;
+        TEST_CALLOC_NONNULL(bad_buf, bad_len);
         memcpy(bad_buf, good_buf, bad_len);
 
         TEST_ASSERT(mbedtls_ssl_session_load(&session, bad_buf, bad_len)
@@ -1908,6 +1908,8 @@
             *byte ^= corrupted_bit;
         }
     }
+
+exit:
     USE_PSA_DONE();
 }
 /* END_CASE */
@@ -2270,8 +2272,10 @@
     size_t len;
 
     mbedtls_ssl_init(&ssl);
-    USE_PSA_INIT();
     mbedtls_ssl_config_init(&conf);
+
+    USE_PSA_INIT();
+
     TEST_EQUAL(mbedtls_ssl_config_defaults(&conf, MBEDTLS_SSL_IS_SERVER,
                                            MBEDTLS_SSL_TRANSPORT_DATAGRAM,
                                            MBEDTLS_SSL_PRESET_DEFAULT),
diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index 6e32792..8c72e5a 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -431,7 +431,6 @@
     TEST_EQUAL(strcmp(buf, result_str), 0);
 
 exit:
-
     mbedtls_x509_crt_free(&crt);
     USE_PSA_DONE();
 }
@@ -675,7 +674,7 @@
 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
     /* CRLs aren't supported with CA callbacks, so skip the CA callback
      * version of the test if CRLs are in use. */
-    if (crl_file == NULL || strcmp(crl_file, "") == 0) {
+    if (strcmp(crl_file, "") == 0) {
         flags = 0;
 
         res = mbedtls_x509_crt_verify_with_ca_cb(&crt,
@@ -864,9 +863,8 @@
 
     TEST_EQUAL(ret, exp_ret);
 
-    mbedtls_free(name);
-
 exit:
+    mbedtls_free(name);
     USE_PSA_DONE();
 }
 /* END_CASE */
@@ -1252,6 +1250,7 @@
     int ret;
 
     USE_PSA_INIT();
+
     oid.tag = MBEDTLS_ASN1_OID;
     oid.p   = buf->x;
     oid.len   = buf->len;
@@ -1279,6 +1278,7 @@
     char num_buf[100];
 
     USE_PSA_INIT();
+
     memset(num_buf, 0x2a, sizeof(num_buf));
 
     oid.tag = MBEDTLS_ASN1_OID;
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index b4509e2..ad0f2a6 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -457,16 +457,16 @@
     int ret;
     size_t len = 0;
     mbedtls_asn1_named_data *names = NULL;
-    mbedtls_x509_name parsed, *parsed_cur, *parsed_prv;
-    unsigned char buf[1024], out[1024], *c;
+    mbedtls_x509_name parsed;
+    memset(&parsed, 0, sizeof(parsed));
+    mbedtls_x509_name *parsed_cur = NULL;
+    mbedtls_x509_name *parsed_prv = NULL;
+    unsigned char buf[1024] = { 0 };
+    unsigned char out[1024] = { 0 };
+    unsigned char *c = buf + sizeof(buf);
 
     USE_PSA_INIT();
 
-    memset(&parsed, 0, sizeof(parsed));
-    memset(out, 0, sizeof(out));
-    memset(buf, 0, sizeof(buf));
-    c = buf + sizeof(buf);
-
     ret = mbedtls_x509_string_to_names(&names, name);
     TEST_ASSERT(ret == result);