diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data
index 1933d3f..ffa526d 100644
--- a/tests/suites/test_suite_ecp.data
+++ b/tests/suites/test_suite_ecp.data
@@ -88,6 +88,14 @@
 depends_on:MBEDTLS_ECP_DP_SECP192R1_ENABLED
 ecp_write_binary:MBEDTLS_ECP_DP_SECP192R1:"48d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":"93112b28345b7d1d7799611e49bea9d8290cb2d7afe1f9f3":"01":MBEDTLS_ECP_PF_COMPRESSED:"0348d8082a3a1e3112bc03a8ef2f6d40d0a77a6f8e00cc9933":25:0
 
+ECP write binary #10 (Montgomery, buffer just fits)
+depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+ecp_write_binary:MBEDTLS_ECP_DP_CURVE25519:"11223344556677889900aabbccddeeff11223344556677889900aabbccddeeff":"0":"1":MBEDTLS_ECP_PF_COMPRESSED:"ffeeddccbbaa00998877665544332211ffeeddccbbaa00998877665544332211":32:0
+
+ECP write binary #11 (Montgomery, buffer too small)
+depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+ecp_write_binary:MBEDTLS_ECP_DP_CURVE25519:"11223344556677889900aabbccddeeff11223344556677889900aabbccddeeff":"0":"1":MBEDTLS_ECP_PF_COMPRESSED:"ffeeddccbbaa00998877665544332211ffeeddccbbaa00998877665544332211":31:MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+
 ECP read binary #1 (zero, invalid ilen)
 depends_on:MBEDTLS_ECP_DP_SECP192R1_ENABLED
 ecp_read_binary:MBEDTLS_ECP_DP_SECP192R1:"0000":"01":"01":"00":MBEDTLS_ERR_ECP_BAD_INPUT_DATA