Fix ecp_tls_read_group's signature
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 50de46a..64e0147 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -377,6 +377,7 @@
 {
     ecp_group grp;
     unsigned char buf[10];
+    const unsigned char *vbuf = buf;
     int len, ret;
 
     ecp_group_init( &grp );
@@ -384,11 +385,14 @@
 
     len = unhexify( buf, {record} );
 
-    ret = ecp_tls_read_group( &grp, buf, len );
+    ret = ecp_tls_read_group( &grp, &vbuf, len );
 
     TEST_ASSERT( ret == {ret} );
     if( ret == 0)
+    {
         TEST_ASSERT( mpi_msb( &grp.P ) == {bits} );
+        TEST_ASSERT( *vbuf == 0x00 );
+    }
 
     ecp_group_free( &grp );
 }
@@ -399,6 +403,7 @@
 {
     ecp_group grp1, grp2;
     unsigned char buf[10];
+    const unsigned char *vbuf = buf;
     size_t len;
     int ret;
 
@@ -409,7 +414,7 @@
     TEST_ASSERT( ecp_use_known_dp( &grp1, POLARSSL_ECP_DP_{id} ) == 0 );
 
     TEST_ASSERT( ecp_tls_write_group( &grp1, &len, buf, 10 ) == 0 );
-    TEST_ASSERT( ( ret = ecp_tls_read_group( &grp2, buf, len ) ) == 0 );
+    TEST_ASSERT( ( ret = ecp_tls_read_group( &grp2, &vbuf, len ) ) == 0 );
 
     if( ret == 0 )
     {