Add MPI write tests when the MPI object has a leading zero limb

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_asn1write.data b/tests/suites/test_suite_asn1write.data
index 01064f5..f2c32ec 100644
--- a/tests/suites/test_suite_asn1write.data
+++ b/tests/suites/test_suite_asn1write.data
@@ -100,9 +100,15 @@
 ASN.1 Write mpi 0x7f
 mbedtls_asn1_write_mpi:"7f":"02017f"
 
+ASN.1 Write mpi 0x7f with leading 0 limb
+mbedtls_asn1_write_mpi:"00000000000000007f":"02017f"
+
 ASN.1 Write mpi 0x80
 mbedtls_asn1_write_mpi:"80":"02020080"
 
+ASN.1 Write mpi 0x80 with leading 0 limb
+mbedtls_asn1_write_mpi:"000000000000000080":"02020080"
+
 ASN.1 Write mpi 0xff
 mbedtls_asn1_write_mpi:"ff":"020200ff"