py/modmath: Check for zero division in log with 2 args.

Author: dpgeorge

py/modmath.c

@@ -168,6 +168,8 @@ STATIC mp_obj_t mp_math_log(size_t n_args, const mp_obj_t *args) {
  mp_float_t base = mp_obj_get_float(args[1]);
  if (base <= (mp_float_t)0.0) {
  math_error();
+ } else if (base == (mp_float_t)1.0) {
+ mp_raise_msg(&mp_type_ZeroDivisionError, "division by zero");
  }
  return mp_obj_new_float(l / MICROPY_FLOAT_C_FUN(log)(base));
  }

tests/float/math_fun.py

@@ -51,13 +51,13 @@
  ('atan2', atan2, ((1., 0.), (0., 1.), (2., 0.5), (-3., 5.), (-3., -4.),)),
  ('fmod', fmod, ((1., 1.), (0., 1.), (2., 0.5), (-3., 5.), (-3., -4.),)),
  ('ldexp', ldexp, ((1., 0), (0., 1), (2., 2), (3., -2), (-3., -4),)),
- ('log', log, ((2., 2.), (3., 2.), (4., 5.), (0., 1.), (1., 0.), (-1., 1.), (1., -1.))),
+ ('log', log, ((2., 2.), (3., 2.), (4., 5.), (0., 1.), (1., 0.), (-1., 1.), (1., -1.), (2., 1.))),
  ]
 
 for function_name, function, test_vals in binary_functions:
  print(function_name)
  for value1, value2 in test_vals:
  try:
  print("{:.5g}".format(function(value1, value2)))
- except ValueError as e:
- print(str(e))
+ except (ValueError, ZeroDivisionError) as e:
+ print(type(e))