def find(specifier, condition, settings=None, random=None):
settings = settings or Settings(
max_examples=2000,
min_satisfying_examples=0,
)
search = strategy(specifier, settings)
random = random or Random()
def template_condition(template):
return assume(condition(search.reify(template)))
template_condition.__name__ = condition.__name__
tracker = Tracker()
try:
return search.reify(
best_satisfying_template(
search,
random,
template_condition,
settings,
None,
tracker=tracker,
))
except NoSuchExample:
if search.size_upper_bound <= len(tracker):
raise DefinitelyNoSuchExample(
get_pretty_function_description(condition),
search.size_upper_bound,
)
raise NoSuchExample(get_pretty_function_description(condition))
def find(specifier, condition, settings=None, random=None, storage=None):
settings = settings or Settings(
max_examples=2000,
min_satisfying_examples=0,
max_shrinks=2000,
)
search = strategy(specifier, settings)
if storage is None and settings.database is not None:
storage = settings.database.storage(
u'find(%s)' %
(binascii.hexlify(function_digest(condition)).decode(u'ascii'), ))
random = random or Random()
successful_examples = [0]
def template_condition(template):
with BuildContext():
result = search.reify(template)
success = condition(result)
if success:
successful_examples[0] += 1
if not successful_examples[0]:
verbose_report(lambda: u'Trying example %s' % (repr(result), ))
elif success:
if successful_examples[0] == 1:
verbose_report(lambda: u'Found satisfying example %s' %
(repr(result), ))
else:
verbose_report(lambda: u'Shrunk example to %s' %
(repr(result), ))
return success
template_condition.__name__ = condition.__name__
tracker = Tracker()
try:
template = best_satisfying_template(
search,
random,
template_condition,
settings,
tracker=tracker,
max_parameter_tries=2,
storage=storage,
)
with BuildContext():
return search.reify(template)
except Timeout:
raise
except NoSuchExample:
if search.template_upper_bound <= len(tracker):
raise DefinitelyNoSuchExample(
get_pretty_function_description(condition),
search.template_upper_bound,
)
raise NoSuchExample(get_pretty_function_description(condition))
def find(specifier, condition, settings=None, random=None):
settings = settings or Settings(
max_examples=2000,
min_satisfying_examples=0,
)
search = strategy(specifier, settings)
random = random or Random()
successful_examples = [0]
def template_condition(template):
result = search.reify(template)
success = condition(result)
if success:
successful_examples[0] += 1
if not successful_examples[0]:
verbose_report(lambda: 'Trying example %s' % (show(result), ))
elif success:
if successful_examples[0] == 1:
verbose_report(lambda: 'Found satisfying example %s' %
(show(result), ))
else:
verbose_report(lambda: 'Shrunk example to %s' %
(show(result), ))
return assume(success)
template_condition.__name__ = condition.__name__
tracker = Tracker()
try:
return search.reify(
best_satisfying_template(
search,
random,
template_condition,
settings,
None,
tracker=tracker,
))
except NoSuchExample:
if search.size_upper_bound <= len(tracker):
raise DefinitelyNoSuchExample(
get_pretty_function_description(condition),
search.size_upper_bound,
)
raise NoSuchExample(get_pretty_function_description(condition))
def find_satisfying_template(search_strategy,
random,
condition,
tracker,
settings,
storage=None):
"""Attempt to find a template for search_strategy such that condition is
truthy.
Exceptions other than UnsatisfiedAssumption will be immediately propagated.
UnsatisfiedAssumption will indicate that similar examples should be avoided
in future.
Returns such a template as soon as it is found, otherwise stops after
settings.max_examples examples have been considered or settings.timeout
seconds have passed (if settings.timeout > 0).
May raise a variety of exceptions depending on exact circumstances, but
these will all subclass either Unsatisfiable (to indicate not enough
examples were found which did not raise UnsatisfiedAssumption to consider
this a valid test) or NoSuchExample (to indicate that this probably means
that condition is true with very high probability).
"""
satisfying_examples = 0
timed_out = False
max_examples = settings.max_examples
min_satisfying_examples = settings.min_satisfying_examples
start_time = time.time()
if storage:
for example in storage.fetch():
if time_to_call_it_a_day(settings, start_time):
break
tracker.track(example)
try:
if condition(example):
return example
satisfying_examples += 1
except UnsatisfiedAssumption:
pass
build_context = BuildContext(random)
parameter_source = ParameterSource(context=build_context,
strategy=search_strategy,
min_parameters=max(
2, int(float(max_examples) / 10)))
for parameter in islice(parameter_source, max_examples - len(tracker)):
if len(tracker) >= search_strategy.size_upper_bound:
break
if time_to_call_it_a_day(settings, start_time):
break
example = search_strategy.produce_template(build_context, parameter)
if tracker.track(example) > 1:
parameter_source.mark_bad()
continue
try:
if condition(example):
return example
except UnsatisfiedAssumption:
parameter_source.mark_bad()
continue
satisfying_examples += 1
run_time = time.time() - start_time
timed_out = settings.timeout >= 0 and run_time >= settings.timeout
if (satisfying_examples
and len(tracker) >= search_strategy.size_lower_bound):
raise DefinitelyNoSuchExample(
get_pretty_function_description(condition),
satisfying_examples,
)
elif satisfying_examples < min_satisfying_examples:
if timed_out:
raise Timeout(condition, satisfying_examples, run_time)
else:
raise Unsatisfiable(condition, satisfying_examples, run_time)
else:
raise NoSuchExample(get_pretty_function_description(condition))
def find_satisfying_template(
search_strategy,
random,
condition,
tracker,
settings,
storage=None,
max_parameter_tries=None,
):
"""Attempt to find a template for search_strategy such that condition is
truthy.
Exceptions other than UnsatisfiedAssumption will be immediately propagated.
UnsatisfiedAssumption will indicate that similar examples should be avoided
in future.
Returns such a template as soon as it is found, otherwise stops after
settings.max_examples examples have been considered or settings.timeout
seconds have passed (if settings.timeout > 0).
May raise a variety of exceptions depending on exact circumstances, but
these will all subclass either Unsatisfiable (to indicate not enough
examples were found which did not raise UnsatisfiedAssumption to consider
this a valid test) or NoSuchExample (to indicate that this probably means
that condition is true with very high probability).
"""
satisfying_examples = 0
examples_considered = 0
timed_out = False
max_iterations = max(settings.max_iterations, settings.max_examples)
max_examples = min(max_iterations, settings.max_examples)
min_satisfying_examples = min(
settings.min_satisfying_examples,
max_examples,
)
start_time = time.time()
if storage:
for example in storage.fetch(search_strategy):
if examples_considered >= max_iterations:
break
examples_considered += 1
if time_to_call_it_a_day(settings, start_time):
break
tracker.track(example)
try:
if condition(example):
return example
satisfying_examples += 1
except UnsatisfiedAssumption:
pass
if satisfying_examples >= max_examples:
break
parameter_source = ParameterSource(
random=random,
strategy=search_strategy,
max_tries=max_parameter_tries,
)
assert search_strategy.template_upper_bound >= 0
if isinstance(search_strategy.template_upper_bound, float):
assert math.isinf(search_strategy.template_upper_bound)
else:
assert isinstance(search_strategy.template_upper_bound, int)
for parameter in parameter_source: # pragma: no branch
if len(tracker) >= search_strategy.template_upper_bound:
break
if examples_considered >= max_iterations:
break
if satisfying_examples >= max_examples:
break
if time_to_call_it_a_day(settings, start_time):
break
examples_considered += 1
try:
example = search_strategy.draw_template(random, parameter)
except BadTemplateDraw:
debug_report('Failed attempt to draw a template')
parameter_source.mark_bad()
continue
if tracker.track(example) > 1:
debug_report('Skipping duplicate example')
parameter_source.mark_bad()
continue
try:
if condition(example):
return example
except UnsatisfiedAssumption:
parameter_source.mark_bad()
continue
satisfying_examples += 1
run_time = time.time() - start_time
timed_out = settings.timeout >= 0 and run_time >= settings.timeout
if (satisfying_examples
and len(tracker) >= search_strategy.template_upper_bound):
raise DefinitelyNoSuchExample(
get_pretty_function_description(condition),
satisfying_examples,
)
elif satisfying_examples < min_satisfying_examples:
if timed_out:
raise Timeout(
('Ran out of time before finding a satisfying example for '
'%s. Only found %d examples (%d satisfying assumptions) in ' +
'%.2fs.') % (get_pretty_function_description(condition),
len(tracker), satisfying_examples, run_time))
else:
raise Unsatisfiable(
('Unable to satisfy assumptions of hypothesis %s. ' +
'Only %d out of %d examples considered satisfied assumptions')
% (get_pretty_function_description(condition),
satisfying_examples, len(tracker)))
else:
raise NoSuchExample(get_pretty_function_description(condition))
