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Diffstat (limited to 'src/lib/test_stefan.c')
| -rw-r--r-- | src/lib/test_stefan.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/lib/test_stefan.c b/src/lib/test_stefan.c new file mode 100644 index 000000000..838cca769 --- /dev/null +++ b/src/lib/test_stefan.c @@ -0,0 +1,206 @@ +/* + This file is part of TALER + Copyright (C) 2023 Taler Systems SA + + TALER is free software; you can redistribute it and/or modify it under the + terms of the GNU General Public License as published by the Free Software + Foundation; either version 3, or (at your option) any later version. + + TALER is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + A PARTICULAR PURPOSE. See the GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along with + TALER; see the file COPYING. If not, see + <http://www.gnu.org/licenses/> +*/ +/** + * @file lib/test_stefan.c + * @brief test calculations on the STEFAN curve + * @author Christian Grothoff + */ +#include "platform.h" +#include "taler_json_lib.h" +#include <gnunet/gnunet_curl_lib.h> +#include "exchange_api_handle.h" + + +/** + * Check if @a a and @a b are numerically close. + * + * @param a an amount + * @param b an amount + * @return true if both values are quite close + */ +static bool +amount_close (const struct TALER_Amount *a, + const struct TALER_Amount *b) +{ + struct TALER_Amount delta; + + switch (TALER_amount_cmp (a, + b)) + { + case -1: /* a < b */ + GNUNET_assert (0 < + TALER_amount_subtract (&delta, + b, + a)); + break; + case 0: + /* perfect */ + return true; + case 1: /* a > b */ + GNUNET_assert (0 < + TALER_amount_subtract (&delta, + a, + b)); + break; + } + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + "Rounding error is %s\n", + TALER_amount2s (&delta)); + if (delta.value > 0) + { + GNUNET_break (0); + return false; + } + if (delta.fraction > 5000) + { + GNUNET_break (0); + return false; + } + return true; /* let's consider this a rounding error */ +} + + +int +main (int argc, + char **argv) +{ + struct TALER_EXCHANGE_DenomPublicKey dk; + struct TALER_EXCHANGE_Keys keys = { + .denom_keys = &dk, + .num_denom_keys = 1 + }; + struct TALER_Amount brut; + struct TALER_Amount net; + + (void) argc; + (void) argv; + GNUNET_log_setup ("test-stefan", + "INFO", + NULL); + GNUNET_assert (GNUNET_OK == + TALER_string_to_amount ("MAGIC:0.13", + &dk.value)); + GNUNET_assert (GNUNET_OK == + TALER_string_to_amount ("MAGIC:1", + &keys.stefan_abs)); + GNUNET_assert (GNUNET_OK == + TALER_string_to_amount ("MAGIC:0.13", + &keys.stefan_log)); + keys.stefan_lin = 1.15; + GNUNET_assert (GNUNET_OK == + TALER_string_to_amount ("MAGIC:4", + &brut)); + GNUNET_log_skip (1, + GNUNET_NO); + GNUNET_assert (GNUNET_SYSERR == + TALER_EXCHANGE_keys_stefan_b2n (&keys, + &brut, + &net)); + GNUNET_assert (GNUNET_OK == + TALER_string_to_amount ("MAGIC:4", + &net)); + GNUNET_log_skip (1, + GNUNET_NO); + GNUNET_assert (GNUNET_SYSERR == + TALER_EXCHANGE_keys_stefan_n2b (&keys, + &net, + &brut)); + keys.stefan_lin = 1.0; + GNUNET_assert (GNUNET_OK == + TALER_string_to_amount ("MAGIC:4", + &brut)); + GNUNET_log_skip (1, + GNUNET_NO); + GNUNET_assert (GNUNET_SYSERR == + TALER_EXCHANGE_keys_stefan_b2n (&keys, + &brut, + &net)); + GNUNET_assert (GNUNET_OK == + TALER_string_to_amount ("MAGIC:4", + &net)); + GNUNET_log_skip (1, + GNUNET_NO); + GNUNET_assert (GNUNET_SYSERR == + TALER_EXCHANGE_keys_stefan_n2b (&keys, + &net, + &brut)); + GNUNET_assert (0 == GNUNET_get_log_skip ()); + keys.stefan_lin = 0.1; + + /* try various values for lin and log STEFAN values */ + for (unsigned int li = 1; li < 13; li += 1) + { + keys.stefan_lin = 1.0 * li / 100.0; + + for (unsigned int lx = 1; lx < 100; lx += 1) + { + keys.stefan_log.fraction = lx * TALER_AMOUNT_FRAC_BASE / 100; + + /* Check brutto-to-netto is stable */ + for (unsigned int i = 0; i<10; i++) + { + struct TALER_Amount rval; + + brut.value = i; + brut.fraction = i * TALER_AMOUNT_FRAC_BASE / 10; + GNUNET_assert (GNUNET_SYSERR != + TALER_EXCHANGE_keys_stefan_b2n (&keys, + &brut, + &net)); + GNUNET_assert (GNUNET_SYSERR != + TALER_EXCHANGE_keys_stefan_n2b (&keys, + &net, + &rval)); + if (TALER_amount_is_zero (&net)) + GNUNET_assert (TALER_amount_is_zero (&rval)); + else + { + GNUNET_assert (amount_close (&brut, + &rval)); + TALER_EXCHANGE_keys_stefan_round (&keys, + &rval); + GNUNET_assert (amount_close (&brut, + &rval)); + } + } + + /* Check netto-to-brutto is stable */ + for (unsigned int i = 0; i<10; i++) + { + struct TALER_Amount rval; + + net.value = i; + net.fraction = i * TALER_AMOUNT_FRAC_BASE / 10; + GNUNET_assert (GNUNET_SYSERR != + TALER_EXCHANGE_keys_stefan_n2b (&keys, + &net, + &brut)); + GNUNET_assert (GNUNET_SYSERR != + TALER_EXCHANGE_keys_stefan_b2n (&keys, + &brut, + &rval)); + GNUNET_assert (amount_close (&net, + &rval)); + TALER_EXCHANGE_keys_stefan_round (&keys, + &rval); + GNUNET_assert (amount_close (&net, + &rval)); + } + } + } + return 0; +} |