Add little endian export to Bignum
The function `mbedtls_mpi_write_binary()` writes big endian byte order,
but we need to be able to write little endian in some caseses. (For
example when handling keys corresponding to Montgomery curves.)
Used `echo xx | tac -rs ..` to transform the test data to little endian.
diff --git a/tests/suites/test_suite_mpi.data b/tests/suites/test_suite_mpi.data
index 7ad7ef6..f2be148 100644
--- a/tests/suites/test_suite_mpi.data
+++ b/tests/suites/test_suite_mpi.data
@@ -70,6 +70,15 @@
Test mbedtls_mpi_write_binary #2 (Buffer too small)
mbedtls_mpi_write_binary:16:"123123123123123123123123123":"23123123123123123123123123":13:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+Base test mbedtls_mpi_write_binary_le #1
+mbedtls_mpi_write_binary_le:10:"56125680981752282334141896320372489490613963693556392520816017892111350604111697682705498319512049040516698827829292076808006940873974979584527073481012636016353913462376755556720019831187364993587901952757307830896531678727717924":"24448b952fbbef93f89286ba330e62528b151eac265cc8ce3038519d09e148af89288e91f48b41acad55d9dc5e2b18097c106be4ce132721bf6359eaf403e7ff90623e8866ee5c192320418daa682f144adedf84f25de11f49d1fe009d374109":200:0
+
+Test mbedtls_mpi_write_binary_le #1 (Buffer just fits)
+mbedtls_mpi_write_binary_le:16:"123123123123123123123123123":"2331122331122331122331122301":14:0
+
+Test mbedtls_mpi_write_binary_le #2 (Buffer too small)
+mbedtls_mpi_write_binary_le:16:"123123123123123123123123123":"23311223311223311223311223":13:MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL
+
Base test mbedtls_mpi_read_file #1
mbedtls_mpi_read_file:10:"data_files/mpi_10":"01f55332c3a48b910f9942f6c914e58bef37a47ee45cb164a5b6b8d1006bf59a059c21449939ebebfdf517d2e1dbac88010d7b1f141e997bd6801ddaec9d05910f4f2de2b2c4d714e2c14a72fc7f17aa428d59c531627f09":0