diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data
index ac57a68..1dd963a 100644
--- a/tests/suites/test_suite_ecp.data
+++ b/tests/suites/test_suite_ecp.data
@@ -752,6 +752,42 @@
 depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
 ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"f12a1320760270a83cbffd53f6031ef76a5d86c8a204f2c30ca9ebf51f0f0ea7":65:0
 
+ECP write key: secp256r1, output short by 1
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"f12a1320760270a83cbffd53f6031ef76a5d86c8a204f2c30ca9ebf51f0f0ea7":31:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
+ECP write key: secp256r1, output_size=1
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"f12a1320760270a83cbffd53f6031ef76a5d86c8a204f2c30ca9ebf51f0f0ea7":1:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
+ECP write key: secp256r1, output_size=0
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"f12a1320760270a83cbffd53f6031ef76a5d86c8a204f2c30ca9ebf51f0f0ea7":0:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
+ECP write key: secp256r1, top byte = 0, output_size=32
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"00ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff":32:0
+
+ECP write key: secp256r1, top byte = 0, output_size=31 (fits)
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"00ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff":31:0
+
+ECP write key: secp256r1, top byte = 0, output_size=30 (too small)
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"00ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff":30:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
+ECP write key: secp256r1, mostly-0 key, output_size=32
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"0000000000000000000000000000000000000000000000000000000000000001":32:0
+
+ECP write key: secp256r1, mostly-0 key, output_size=31 (fits)
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"0000000000000000000000000000000000000000000000000000000000000001":31:0
+
+ECP write key: secp256r1, mostly-0 key, output_size=1 (fits)
+depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP256R1:"0000000000000000000000000000000000000000000000000000000000000001":1:0
+
 ECP write key: secp384r1, nominal
 depends_on:MBEDTLS_ECP_DP_SECP384R1_ENABLED
 ecp_write_key:MBEDTLS_ECP_DP_SECP384R1:"d27335ea71664af244dd14e9fd1260715dfd8a7965571c48d709ee7a7962a156d706a90cbcb5df2986f05feadb9376f1":48:0
@@ -768,6 +804,18 @@
 depends_on:MBEDTLS_ECP_DP_SECP384R1_ENABLED
 ecp_write_key:MBEDTLS_ECP_DP_SECP384R1:"d27335ea71664af244dd14e9fd1260715dfd8a7965571c48d709ee7a7962a156d706a90cbcb5df2986f05feadb9376f1":97:0
 
+ECP write key: secp384r1, output short by 1
+depends_on:MBEDTLS_ECP_DP_SECP384R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP384R1:"d27335ea71664af244dd14e9fd1260715dfd8a7965571c48d709ee7a7962a156d706a90cbcb5df2986f05feadb9376f1":47:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
+ECP write key: secp384r1, output_size=1
+depends_on:MBEDTLS_ECP_DP_SECP384R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP384R1:"d27335ea71664af244dd14e9fd1260715dfd8a7965571c48d709ee7a7962a156d706a90cbcb5df2986f05feadb9376f1":1:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
+ECP write key: secp384r1, output_size=0
+depends_on:MBEDTLS_ECP_DP_SECP384R1_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_SECP384R1:"d27335ea71664af244dd14e9fd1260715dfd8a7965571c48d709ee7a7962a156d706a90cbcb5df2986f05feadb9376f1":0:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
 ECP write key: Curve25519, nominal
 depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
 ecp_write_key:MBEDTLS_ECP_DP_CURVE25519:"a046e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449a44":32:0
@@ -784,6 +832,26 @@
 depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
 ecp_write_key:MBEDTLS_ECP_DP_CURVE25519:"a046e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449a44":65:0
 
+ECP write key: Curve25519, output short by 1
+depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE25519:"a046e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449a44":31:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
+ECP write key: Curve25519, output_size=1
+depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE25519:"a046e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449a44":1:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
+ECP write key: Curve25519, output_size=0
+depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE25519:"a046e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449a44":0:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
+ECP write key: Curve25519, mostly-0 key, output_size=32
+depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE25519:"0000000000000000000000000000000000000000000000000000000000000040":32:0
+
+ECP write key: Curve25519, mostly-0 key, output_size=31
+depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE25519:"0000000000000000000000000000000000000000000000000000000000000040":31:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
 ECP write key: Curve448, nominal
 depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
 ecp_write_key:MBEDTLS_ECP_DP_CURVE448:"3c262fddf9ec8e88495266fea19a34d28882acef045104d0d1aae121700a779c984c24f8cdd78fbff44943eba368f54b29259a4f1c600ad3":56:0
@@ -800,6 +868,26 @@
 depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
 ecp_write_key:MBEDTLS_ECP_DP_CURVE448:"3c262fddf9ec8e88495266fea19a34d28882acef045104d0d1aae121700a779c984c24f8cdd78fbff44943eba368f54b29259a4f1c600ad3":113:0
 
+ECP write key: Curve448, output short by 1
+depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE448:"3c262fddf9ec8e88495266fea19a34d28882acef045104d0d1aae121700a779c984c24f8cdd78fbff44943eba368f54b29259a4f1c600ad3":55:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
+ECP write key: Curve448, output_size=1
+depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE448:"3c262fddf9ec8e88495266fea19a34d28882acef045104d0d1aae121700a779c984c24f8cdd78fbff44943eba368f54b29259a4f1c600ad3":1:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
+ECP write key: Curve448, output_size=0
+depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE448:"3c262fddf9ec8e88495266fea19a34d28882acef045104d0d1aae121700a779c984c24f8cdd78fbff44943eba368f54b29259a4f1c600ad3":0:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
+ECP write key: Curve448, mostly-0 key, output_size=56
+depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE448:"0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000080":56:0
+
+ECP write key: Curve448, mostly-0 key, output_size=55
+depends_on:MBEDTLS_ECP_DP_CURVE448_ENABLED
+ecp_write_key:MBEDTLS_ECP_DP_CURVE448:"0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000080":55:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
 ECP mod p192 small (more than 192 bits, less limbs than 2 * 192 bits)
 depends_on:MBEDTLS_ECP_DP_SECP192R1_ENABLED:MBEDTLS_ECP_NIST_OPTIM
 ecp_fast_mod:MBEDTLS_ECP_DP_SECP192R1:"0100000000000103010000000000010201000000000001010100000000000100"
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 80fff20..9cf0ce1 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -1252,16 +1252,18 @@
 
     if (expected_ret == 0) {
         size_t length = (key.grp.nbits + 7) / 8;
-        TEST_LE_U(length, exported_size);
-
         const unsigned char *key_start = NULL;
         const unsigned char *zeros_start = NULL;
         switch (mbedtls_ecp_get_type(&key.grp)) {
             case MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS:
+                if ((size_t) exported_size < length) {
+                    length = exported_size;
+                }
                 key_start = exported + exported_size - length;
                 zeros_start = exported;
                 break;
             case MBEDTLS_ECP_TYPE_MONTGOMERY:
+                TEST_LE_U(length, exported_size);
                 key_start = exported;
                 zeros_start = exported + length;
                 break;
@@ -1269,11 +1271,22 @@
                 TEST_FAIL("Unknown ECP curve type");
                 break;
         }
-        TEST_MEMORY_COMPARE(in_key->x, in_key->len,
-                            key_start, length);
-        for (size_t i = 0; i < exported_size - length; i++) {
-            mbedtls_test_set_step(i);
-            TEST_EQUAL(zeros_start[i], 0);
+
+        if (length < in_key->len) {
+            /* Shorter output (only possible with Weierstrass keys) */
+            for (size_t i = 0; i < in_key->len - length; i++) {
+                mbedtls_test_set_step(i);
+                TEST_EQUAL(in_key->x[i], 0);
+            }
+            TEST_MEMORY_COMPARE(in_key->x + in_key->len - length, length,
+                                key_start, length);
+        } else {
+            TEST_MEMORY_COMPARE(in_key->x, in_key->len,
+                                key_start, length);
+            for (size_t i = 0; i < exported_size - length; i++) {
+                mbedtls_test_set_step(i);
+                TEST_EQUAL(zeros_start[i], 0);
+            }
         }
     }