Test mbedtls_mpi_fill_random

Positive tests: test that the RNG has the expected size, given that we
know how many leading zeros it has because we know how the function
consumes bytes and when the test RNG produces null bytes.

Negative tests: test that if the RNG is willing to emit less than the
number of wanted bytes, the function fails.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_mpi.data b/tests/suites/test_suite_mpi.data
index 00926ff..a3e4eb9 100644
--- a/tests/suites/test_suite_mpi.data
+++ b/tests/suites/test_suite_mpi.data
@@ -929,6 +929,48 @@
 Test bit set (Invalid bit value)
 mbedtls_mpi_set_bit:16:"00":5:2:16:"00":MBEDTLS_ERR_MPI_BAD_INPUT_DATA
 
+Fill random: 0 bytes
+mpi_fill_random:0:0:0
+
+Fill random: 1 byte, good
+mpi_fill_random:1:1:0
+
+Fill random: 2 bytes, good, no leading zero
+mpi_fill_random:2:2:0
+
+Fill random: 2 bytes, good, 1 leading zero
+mpi_fill_random:2:256:0
+
+Fill random: MAX_SIZE - 7, good
+mpi_fill_random:MBEDTLS_MPI_MAX_SIZE - 7:MBEDTLS_MPI_MAX_SIZE - 7:0
+
+Fill random: MAX_SIZE, good
+mpi_fill_random:MBEDTLS_MPI_MAX_SIZE:MBEDTLS_MPI_MAX_SIZE:0
+
+Fill random: 1 byte, RNG failure
+mpi_fill_random:1:0:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
+Fill random: 2 bytes, RNG failure after 1 byte
+mpi_fill_random:2:1:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
+Fill random: 4 bytes, RNG failure after 3 bytes
+mpi_fill_random:4:3:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
+Fill random: 8 bytes, RNG failure after 7 bytes
+mpi_fill_random:8:7:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
+Fill random: 16 bytes, RNG failure after 1 bytes
+mpi_fill_random:16:1:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
+Fill random: 16 bytes, RNG failure after 8 bytes
+mpi_fill_random:16:8:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
+Fill random: 16 bytes, RNG failure after 15 bytes
+mpi_fill_random:16:15:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
+Fill random: MAX_SIZE bytes, RNG failure after MAX_SIZE-1 bytes
+mpi_fill_random:MBEDTLS_MPI_MAX_SIZE:MBEDTLS_MPI_MAX_SIZE-1:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
+
 MPI Selftest
 depends_on:MBEDTLS_SELF_TEST
 mpi_selftest: