def simplify_template_such_that(
search_strategy, random, t, f, tracker, settings, start_time
):
"""Perform a greedy search to produce a "simplest" version of a template
that satisfies some predicate.
Care is taken to avoid cycles in simplify.
f should produce the same result deterministically. This function may
raise an error given f such that f(t) returns False sometimes and True
some other times.
If f throws UnsatisfiedAssumption this will be treated the same as if
it returned False.
"""
assert isinstance(random, Random)
yield t
successful_shrinks = 0
changed = True
while changed and successful_shrinks < settings.max_shrinks:
changed = False
for simplify in search_strategy.simplifiers(random, t):
debug_report('Applying simplification pass %s' % (
simplify.__name__,
))
while True:
simpler = simplify(random, t)
for s in simpler:
if tracker.track(s) > 1:
continue
try:
if f(s):
successful_shrinks += 1
changed = True
yield s
t = s
break
except UnsatisfiedAssumption:
pass
if time_to_call_it_a_day(settings, start_time):
return
else:
break
if successful_shrinks >= settings.max_shrinks:
break
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(u'Failed attempt to draw a template')
parameter_source.mark_bad()
continue
if tracker.track(example) > 1:
debug_report(u'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((
u'Ran out of time before finding a satisfying example for '
u'%s. Only found %d examples (%d satisfying assumptions) in ' +
u'%.2fs.'
) % (
get_pretty_function_description(condition),
len(tracker), satisfying_examples, run_time
))
else:
raise Unsatisfiable((
u'Unable to satisfy assumptions of hypothesis %s. ' +
u'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))
def simplify_template_such_that(
search_strategy, random, t, f, tracker, settings, start_time
):
"""Perform a greedy search to produce a "simplest" version of a template
that satisfies some predicate.
Care is taken to avoid cycles in simplify.
f should produce the same result deterministically. This function may
raise an error given f such that f(t) returns False sometimes and True
some other times.
If f throws UnsatisfiedAssumption this will be treated the same as if
it returned False.
"""
assert isinstance(random, Random)
yield t
successful_shrinks = 0
changed = True
max_warmup = 5
warmup = 0
while (
(changed or warmup < max_warmup) and
successful_shrinks < settings.max_shrinks
):
changed = False
warmup += 1
if warmup < max_warmup:
debug_report(u'Running warmup simplification round %d' % (
warmup
))
elif warmup == max_warmup:
debug_report(u'Warmup is done. Moving on to fully simplifying')
any_simplifiers = False
for simplify in search_strategy.simplifiers(random, t):
debug_report(u'Applying simplification pass %s' % (
simplify.__name__,
))
any_simplifiers = True
any_shrinks = False
while True:
simpler = simplify(random, t)
if warmup < max_warmup:
simpler = islice(simpler, warmup)
for s in simpler:
any_shrinks = True
if time_to_call_it_a_day(settings, start_time):
return
if tracker.track(s) > 1:
debug_report(
u'Skipping simplifying to duplicate %s' % (
unicode_safe_repr(s),
))
continue
try:
if f(s):
successful_shrinks += 1
changed = True
yield s
t = s
break
else:
yield t
except UnsatisfiedAssumption:
pass
else:
break
if not any_shrinks:
debug_report(u'No shrinks possible')
if successful_shrinks >= settings.max_shrinks:
break
if not any_simplifiers:
debug_report(u'No simplifiers for template %s' % (
unicode_safe_repr(t),
))
break
def test_does_print_debug_in_debug():
with settings(verbosity=Verbosity.debug):
with capture_out() as o:
debug_report(u'Hi')
assert u'Hi' in o.getvalue()
def test_does_not_print_debug_in_verbose():
with settings(verbosity=Verbosity.verbose):
with capture_out() as o:
debug_report(u'Hi')
assert not o.getvalue()
def debug(self, message):
with self.settings:
debug_report(message)
def f(x):
debug_report('Hi')
def f(x):
debug_report('Hi')
def debug(self, message):
with local_settings(self.settings):
debug_report(message)
def test_does_print_debug_in_debug():
with settings(verbosity=Verbosity.debug):
with capture_out() as o:
debug_report(u'Hi')
assert u'Hi' in o.getvalue()
def test_does_not_print_debug_in_verbose():
with settings(verbosity=Verbosity.verbose):
with capture_out() as o:
debug_report(u'Hi')
assert not o.getvalue()
def f(x):
debug_report("Hi")
def f(x):
debug_report("Hi")
def debug(self, message):
with self.settings:
debug_report(message)
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))
def simplify_template_such_that(search_strategy, random, t, f, tracker,
settings, start_time):
"""Perform a greedy search to produce a "simplest" version of a template
that satisfies some predicate.
Care is taken to avoid cycles in simplify.
f should produce the same result deterministically. This function may
raise an error given f such that f(t) returns False sometimes and True
some other times.
If f throws UnsatisfiedAssumption this will be treated the same as if
it returned False.
"""
yield t
try:
if settings.max_shrinks <= 0 or not f(t):
return
except UnsatisfiedAssumption:
return
successful_shrinks = 0
changed = True
max_warmup = 5
warmup = 0
while ((changed or warmup < max_warmup)
and successful_shrinks < settings.max_shrinks):
changed = False
warmup += 1
if warmup < max_warmup:
debug_report('Running warmup simplification round %d' % (warmup))
elif warmup == max_warmup:
debug_report('Warmup is done. Moving on to fully simplifying')
any_simplifiers = False
for simplify in search_strategy.simplifiers(random, t):
debug_report('Applying simplification pass %s' %
(simplify.__name__, ))
any_simplifiers = True
any_shrinks = False
while successful_shrinks < settings.max_shrinks:
simpler = simplify(random, t)
if warmup < max_warmup:
simpler = islice(simpler, warmup)
for s in simpler:
any_shrinks = True
if time_to_call_it_a_day(settings, start_time):
return
if tracker.track(s) > 1:
debug_report('Skipping simplifying to duplicate %s' %
(repr(s), ))
continue
try:
if f(s):
successful_shrinks += 1
changed = True
yield s
t = s
break
else:
yield t
except UnsatisfiedAssumption:
pass
else:
break
if not any_shrinks:
debug_report('No shrinks possible')
if not any_simplifiers:
debug_report('No simplifiers for template %s' % (repr(t), ))
break