Add tests to cover PKCS1 v1.5 signature functions.

The reported memory leak should have been spotted by
make memcheck
But it wasn't. Keeping the tests for better coverage.
diff --git a/tests/suites/test_suite_pkcs1_v15.function b/tests/suites/test_suite_pkcs1_v15.function
index 90460f1..ce8bf58 100644
--- a/tests/suites/test_suite_pkcs1_v15.function
+++ b/tests/suites/test_suite_pkcs1_v15.function
@@ -108,3 +108,160 @@
 }
 /* END_CASE */
 
+/* BEGIN_CASE */
+void pkcs1_rsassa_v15_sign( int mod, int radix_P, char *input_P, int radix_Q,
+                            char *input_Q, int radix_N, char *input_N,
+                            int radix_E, char *input_E, int digest, int hash,
+                            char *message_hex_string, char *salt,
+                            char *result_hex_str, int result )
+{
+    unsigned char message_str[1000];
+    unsigned char hash_result[1000];
+    unsigned char output[1000];
+    unsigned char output_str[1000];
+    unsigned char rnd_buf[1000];
+    mbedtls_rsa_context ctx;
+    mbedtls_mpi P1, Q1, H, G;
+    size_t msg_len;
+    rnd_buf_info info;
+
+    info.length = unhexify( rnd_buf, salt );
+    info.buf = rnd_buf;
+
+    mbedtls_mpi_init( &P1 ); mbedtls_mpi_init( &Q1 ); mbedtls_mpi_init( &H ); mbedtls_mpi_init( &G );
+    mbedtls_rsa_init( &ctx, MBEDTLS_RSA_PKCS_V15, hash );
+
+    memset( message_str, 0x00, 1000 );
+    memset( hash_result, 0x00, 1000 );
+    memset( output, 0x00, 1000 );
+    memset( output_str, 0x00, 1000 );
+
+    ctx.len = mod / 8 + ( ( mod % 8 ) ? 1 : 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.P, radix_P, input_P ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.Q, radix_Q, input_Q ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.N, radix_N, input_N ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.E, radix_E, input_E ) == 0 );
+
+    TEST_ASSERT( mbedtls_mpi_sub_int( &P1, &ctx.P, 1 ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_sub_int( &Q1, &ctx.Q, 1 ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_mul_mpi( &H, &P1, &Q1 ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_gcd( &G, &ctx.E, &H  ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_inv_mod( &ctx.D , &ctx.E, &H  ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_mod_mpi( &ctx.DP, &ctx.D, &P1 ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_mod_mpi( &ctx.DQ, &ctx.D, &Q1 ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_inv_mod( &ctx.QP, &ctx.Q, &ctx.P ) == 0 );
+
+    TEST_ASSERT( mbedtls_rsa_check_privkey( &ctx ) == 0 );
+
+    msg_len = unhexify( message_str, message_hex_string );
+
+    if( mbedtls_md_info_from_type( digest ) != NULL )
+        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str, msg_len, hash_result ) == 0 );
+
+    TEST_ASSERT( mbedtls_rsa_pkcs1_sign( &ctx, &rnd_buffer_rand, &info, MBEDTLS_RSA_PRIVATE, digest, 0, hash_result, output ) == result );
+    if( result == 0 )
+    {
+        hexify( output_str, output, ctx.len);
+
+        TEST_ASSERT( strcasecmp( (char *) output_str, result_hex_str ) == 0 );
+    }
+
+exit:
+    mbedtls_mpi_free( &P1 ); mbedtls_mpi_free( &Q1 ); mbedtls_mpi_free( &H ); mbedtls_mpi_free( &G );
+    mbedtls_rsa_free( &ctx );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void pkcs1_rsassa_v15_verify( int mod, int radix_N, char *input_N, int radix_E,
+                              char *input_E, int digest, int hash,
+                              char *message_hex_string, char *salt,
+                              char *result_hex_str, int result )
+{
+    unsigned char message_str[1000];
+    unsigned char hash_result[1000];
+    unsigned char result_str[1000];
+    mbedtls_rsa_context ctx;
+    size_t msg_len;
+    ((void) salt);
+
+    mbedtls_rsa_init( &ctx, MBEDTLS_RSA_PKCS_V15, hash );
+    memset( message_str, 0x00, 1000 );
+    memset( hash_result, 0x00, 1000 );
+    memset( result_str, 0x00, 1000 );
+
+    ctx.len = mod / 8 + ( ( mod % 8 ) ? 1 : 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.N, radix_N, input_N ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.E, radix_E, input_E ) == 0 );
+
+    TEST_ASSERT( mbedtls_rsa_check_pubkey( &ctx ) == 0 );
+
+    msg_len = unhexify( message_str, message_hex_string );
+    unhexify( result_str, result_hex_str );
+
+    if( mbedtls_md_info_from_type( digest ) != NULL )
+        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str, msg_len, hash_result ) == 0 );
+
+    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, NULL, NULL, MBEDTLS_RSA_PUBLIC, digest, 0, hash_result, result_str ) == result );
+
+exit:
+    mbedtls_rsa_free( &ctx );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void pkcs1_rsassa_v15_verify_ext( int mod,
+                                  int radix_N, char *input_N,
+                                  int radix_E, char *input_E,
+                                  int msg_digest_id, int ctx_hash,
+                                  int mgf_hash, int salt_len,
+                                  char *message_hex_string,
+                                  char *result_hex_str,
+                                  int result_simple,
+                                  int result_full )
+{
+    unsigned char message_str[1000];
+    unsigned char hash_result[1000];
+    unsigned char result_str[1000];
+    mbedtls_rsa_context ctx;
+    size_t msg_len, hash_len;
+
+    mbedtls_rsa_init( &ctx, MBEDTLS_RSA_PKCS_V15, ctx_hash );
+    memset( message_str, 0x00, 1000 );
+    memset( hash_result, 0x00, 1000 );
+    memset( result_str, 0x00, 1000 );
+
+    ctx.len = mod / 8 + ( ( mod % 8 ) ? 1 : 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.N, radix_N, input_N ) == 0 );
+    TEST_ASSERT( mbedtls_mpi_read_string( &ctx.E, radix_E, input_E ) == 0 );
+
+    TEST_ASSERT( mbedtls_rsa_check_pubkey( &ctx ) == 0 );
+
+    msg_len = unhexify( message_str, message_hex_string );
+    unhexify( result_str, result_hex_str );
+
+    if( msg_digest_id != MBEDTLS_MD_NONE )
+    {
+        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( msg_digest_id ),
+                     message_str, msg_len, hash_result ) == 0 );
+        hash_len = 0;
+    }
+    else
+    {
+        memcpy( hash_result, message_str, msg_len );
+        hash_len = msg_len;
+    }
+
+    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, NULL, NULL, MBEDTLS_RSA_PUBLIC,
+                                   msg_digest_id, hash_len, hash_result,
+                                   result_str ) == result_simple );
+
+    TEST_ASSERT( mbedtls_rsa_rsassa_pss_verify_ext( &ctx, NULL, NULL, MBEDTLS_RSA_PUBLIC,
+                                        msg_digest_id, hash_len, hash_result,
+                                        mgf_hash, salt_len,
+                                        result_str ) == result_full );
+
+exit:
+    mbedtls_rsa_free( &ctx );
+}
+/* END_CASE */