class StateMachineTestCase(TestCase):
settings = Settings(deadline=None, suppress_health_check=HealthCheck.all())
def runTest(self):
run_state_machine_as_test(state_machine_class)
runTest.is_hypothesis_test = True
def run_state_machine_as_test(state_machine_factory, settings=None):
"""Run a state machine definition as a test, either silently doing nothing
or printing a minimal breaking program and raising an exception.
state_machine_factory is anything which returns an instance of
GenericStateMachine when called with no arguments - it can be a class or a
function. settings will be used to control the execution of the test.
"""
if settings is None:
try:
settings = state_machine_factory.TestCase.settings
check_type(Settings, settings,
"state_machine_factory.TestCase.settings")
except AttributeError:
settings = Settings(deadline=None,
suppress_health_check=HealthCheck.all())
check_type(Settings, settings, "settings")
@settings
@given(st.data())
def run_state_machine(factory, data):
machine = factory()
check_type(GenericStateMachine, machine, "state_machine_factory()")
data.conjecture_data.hypothesis_runner = machine
n_steps = settings.stateful_step_count
should_continue = cu.many(data.conjecture_data,
min_size=1,
max_size=n_steps,
average_size=n_steps)
print_steps = (current_build_context().is_final
or current_verbosity() >= Verbosity.debug)
try:
if print_steps:
machine.print_start()
machine.check_invariants()
while should_continue.more():
value = data.conjecture_data.draw(machine.steps())
if print_steps:
machine.print_step(value)
machine.execute_step(value)
machine.check_invariants()
finally:
if print_steps:
machine.print_end()
machine.teardown()
# Use a machine digest to identify stateful tests in the example database
run_state_machine.hypothesis.inner_test._hypothesis_internal_add_digest = function_digest(
state_machine_factory)
# Copy some attributes so @seed and @reproduce_failure "just work"
run_state_machine._hypothesis_internal_use_seed = getattr(
state_machine_factory, "_hypothesis_internal_use_seed", None)
run_state_machine._hypothesis_internal_use_reproduce_failure = getattr(
state_machine_factory, "_hypothesis_internal_use_reproduce_failure",
None)
run_state_machine(state_machine_factory)
def example(self):
# type: () -> Ex
"""Provide an example of the sort of value that this strategy
generates. This is biased to be slightly simpler than is typical for
values from this strategy, for clarity purposes.
This method shouldn't be taken too seriously. It's here for interactive
exploration of the API, not for any sort of real testing.
This method is part of the public API.
"""
if getattr(sys, "ps1", None) is None: # pragma: no branch
# The other branch *is* covered in cover/test_examples.py; but as that
# uses `pexpect` for an interactive session `coverage` doesn't see it.
warnings.warn(
"The `.example()` method is good for exploring strategies, but should "
"only be used interactively. We recommend using `@given` for tests - "
"it performs better, saves and replays failures to avoid flakiness, "
"and reports minimal examples. (strategy: %r)" % (self, ),
NonInteractiveExampleWarning,
)
context = _current_build_context.value
if context is not None:
if context.data is not None and context.data.depth > 0:
raise HypothesisException(
"Using example() inside a strategy definition is a bad "
"idea. Instead consider using hypothesis.strategies.builds() "
"or @hypothesis.strategies.composite to define your strategy."
" See https://hypothesis.readthedocs.io/en/latest/data.html"
"#hypothesis.strategies.builds or "
"https://hypothesis.readthedocs.io/en/latest/data.html"
"#composite-strategies for more details.")
else:
raise HypothesisException(
"Using example() inside a test function is a bad "
"idea. Instead consider using hypothesis.strategies.data() "
"to draw more examples during testing. See "
"https://hypothesis.readthedocs.io/en/latest/data.html"
"#drawing-interactively-in-tests for more details.")
from hypothesis.core import given
# Note: this function has a weird name because it might appear in
# tracebacks, and we want users to know that they can ignore it.
@given(self)
@settings(
database=None,
max_examples=10,
deadline=None,
verbosity=Verbosity.quiet,
phases=(Phase.generate, ),
suppress_health_check=HealthCheck.all(),
)
def example_generating_inner_function(ex):
examples.append(ex)
examples = [] # type: List[Ex]
example_generating_inner_function()
return random_choice(examples)
def run_state_machine_as_test(state_machine_factory, settings=None):
"""Run a state machine definition as a test, either silently doing nothing
or printing a minimal breaking program and raising an exception.
state_machine_factory is anything which returns an instance of
GenericStateMachine when called with no arguments - it can be a class or a
function. settings will be used to control the execution of the test.
"""
if settings is None:
try:
settings = state_machine_factory.TestCase.settings
check_type(Settings, settings, "state_machine_factory.TestCase.settings")
except AttributeError:
settings = Settings(deadline=None, suppress_health_check=HealthCheck.all())
check_type(Settings, settings, "settings")
@settings
@given(st.data())
def run_state_machine(factory, data):
machine = factory()
check_type(GenericStateMachine, machine, "state_machine_factory()")
data.conjecture_data.hypothesis_runner = machine
n_steps = settings.stateful_step_count
should_continue = cu.many(
data.conjecture_data, min_size=1, max_size=n_steps, average_size=n_steps
)
print_steps = (
current_build_context().is_final or current_verbosity() >= Verbosity.debug
)
try:
if print_steps:
machine.print_start()
machine.check_invariants()
while should_continue.more():
value = data.conjecture_data.draw(machine.steps())
if print_steps:
machine.print_step(value)
machine.execute_step(value)
machine.check_invariants()
finally:
if print_steps:
machine.print_end()
machine.teardown()
# Use a machine digest to identify stateful tests in the example database
run_state_machine.hypothesis.inner_test._hypothesis_internal_add_digest = function_digest(
state_machine_factory
)
# Copy some attributes so @seed and @reproduce_failure "just work"
run_state_machine._hypothesis_internal_use_seed = getattr(
state_machine_factory, "_hypothesis_internal_use_seed", None
)
run_state_machine._hypothesis_internal_use_reproduce_failure = getattr(
state_machine_factory, "_hypothesis_internal_use_reproduce_failure", None
)
run_state_machine(state_machine_factory)
def example(self, random=not_set):
# type: (UniqueIdentifier) -> Ex
"""Provide an example of the sort of value that this strategy
generates. This is biased to be slightly simpler than is typical for
values from this strategy, for clarity purposes.
This method shouldn't be taken too seriously. It's here for interactive
exploration of the API, not for any sort of real testing.
This method is part of the public API.
"""
if random is not not_set:
note_deprecation("The random argument does nothing", since="2019-07-08")
context = _current_build_context.value
if context is not None:
if context.data is not None and context.data.depth > 0:
raise HypothesisException(
"Using example() inside a strategy definition is a bad "
"idea. Instead consider using hypothesis.strategies.builds() "
"or @hypothesis.strategies.composite to define your strategy."
" See https://hypothesis.readthedocs.io/en/latest/data.html"
"#hypothesis.strategies.builds or "
"https://hypothesis.readthedocs.io/en/latest/data.html"
"#composite-strategies for more details."
)
else:
raise HypothesisException(
"Using example() inside a test function is a bad "
"idea. Instead consider using hypothesis.strategies.data() "
"to draw more examples during testing. See "
"https://hypothesis.readthedocs.io/en/latest/data.html"
"#drawing-interactively-in-tests for more details."
)
from hypothesis.core import given
# Note: this function has a weird name because it might appear in
# tracebacks, and we want users to know that they can ignore it.
@given(self)
@settings(
database=None,
max_examples=10,
deadline=None,
verbosity=Verbosity.quiet,
phases=(Phase.generate,),
suppress_health_check=HealthCheck.all(),
)
def example_generating_inner_function(ex):
examples.append(ex)
examples = [] # type: List[Ex]
example_generating_inner_function()
return random_choice(examples)
def find(
specifier: SearchStrategy[Ex],
condition: Callable[[Any], bool],
*,
settings: Settings = None,
random: Random = None,
database_key: bytes = None
) -> Ex:
"""Returns the minimal example from the given strategy ``specifier`` that
matches the predicate function ``condition``."""
if settings is None:
settings = Settings(max_examples=2000)
settings = Settings(
settings, suppress_health_check=HealthCheck.all(), report_multiple_bugs=False
)
if database_key is None and settings.database is not None:
database_key = function_digest(condition)
if not isinstance(specifier, SearchStrategy):
raise InvalidArgument(
"Expected SearchStrategy but got %r of type %s"
% (specifier, type(specifier).__name__)
)
specifier.validate()
last = [] # type: List[Ex]
@settings
@given(specifier)
def test(v):
if condition(v):
last[:] = [v]
raise Found()
if random is not None:
test = seed(random.getrandbits(64))(test)
test._hypothesis_internal_is_find = True
test._hypothesis_internal_database_key = database_key
try:
test()
except Found:
return last[0]
raise NoSuchExample(get_pretty_function_description(condition))
def examples(strategy: SearchStrategy) -> List[Tuple[str, ...]]:
"""
This is lifted from:
hypothesis/strategies/_internal/strategies.py
...but adapted to remove restrictions on no of examples generated.
DO NOT USE
TODO:
hypothesis generation is weird...
When called, `example_generating_inner_function` will generate up to
`max_examples` examples (non-unique, but the higher the limit the more
variety you will see, and I believe `intinf` can exhaust the search
space... it stops for simple examples at least)
`example_generating_inner_function` does not return any value, so we have
to 'post' data back into the containing func. I did not yet find a way to
generate incrementally, although you can call `strategy.example()` in a
loop (hypothesis uses `max_examples=10`) and get > 10 unique results, plus
a lot of duplicates. So the max param biases the search space, but which
examples are returned is random.
"""
example_buffer = []
@given(strategy)
@settings(
database=None,
max_examples=intinf,
deadline=None,
verbosity=Verbosity.quiet,
phases=(Phase.generate,),
suppress_health_check=HealthCheck.all(),
)
def example_generating_inner_function(example):
print("inner example:", example)
example_buffer.append(tuple(example))
example_generating_inner_function()
return example_buffer
def run_state_machine_as_test(state_machine_factory, *, settings=None):
"""Run a state machine definition as a test, either silently doing nothing
or printing a minimal breaking program and raising an exception.
state_machine_factory is anything which returns an instance of
RuleBasedStateMachine when called with no arguments - it can be a class or a
function. settings will be used to control the execution of the test.
"""
if settings is None:
try:
settings = state_machine_factory.TestCase.settings
check_type(Settings, settings,
"state_machine_factory.TestCase.settings")
except AttributeError:
settings = Settings(deadline=None,
suppress_health_check=HealthCheck.all())
check_type(Settings, settings, "settings")
@settings
@given(st.data())
def run_state_machine(factory, data):
cd = data.conjecture_data
machine = factory()
check_type(RuleBasedStateMachine, machine, "state_machine_factory()")
cd.hypothesis_runner = machine
print_steps = (current_build_context().is_final
or current_verbosity() >= Verbosity.debug)
try:
if print_steps:
report("state = %s()" % (machine.__class__.__name__, ))
machine.check_invariants()
max_steps = settings.stateful_step_count
steps_run = 0
while True:
# We basically always want to run the maximum number of steps,
# but need to leave a small probability of terminating early
# in order to allow for reducing the number of steps once we
# find a failing test case, so we stop with probability of
# 2 ** -16 during normal operation but force a stop when we've
# generated enough steps.
cd.start_example(STATE_MACHINE_RUN_LABEL)
if steps_run == 0:
cd.draw_bits(16, forced=1)
elif steps_run >= max_steps:
cd.draw_bits(16, forced=0)
break
else:
# All we really care about is whether this value is zero
# or non-zero, so if it's > 1 we discard it and insert a
# replacement value after
cd.start_example(SHOULD_CONTINUE_LABEL)
should_continue_value = cd.draw_bits(16)
if should_continue_value > 1:
cd.stop_example(discard=True)
cd.draw_bits(16,
forced=int(bool(should_continue_value)))
else:
cd.stop_example()
if should_continue_value == 0:
break
steps_run += 1
# Choose a rule to run, preferring an initialize rule if there are
# any which have not been run yet.
if machine._initialize_rules_to_run:
init_rules = [
st.tuples(st.just(rule),
st.fixed_dictionaries(rule.arguments))
for rule in machine._initialize_rules_to_run
]
rule, data = cd.draw(st.one_of(init_rules))
machine._initialize_rules_to_run.remove(rule)
else:
rule, data = cd.draw(machine._rules_strategy)
# Pretty-print the values this rule was called with *before* calling
# _add_result_to_targets, to avoid printing arguments which are also
# a return value using the variable name they are assigned to.
# See https://github.com/HypothesisWorks/hypothesis/issues/2341
if print_steps:
data_to_print = {
k: machine._pretty_print(v)
for k, v in data.items()
}
# Assign 'result' here in case executing the rule fails below
result = multiple()
try:
data = dict(data)
for k, v in list(data.items()):
if isinstance(v, VarReference):
data[k] = machine.names_to_values[v.name]
result = rule.function(machine, **data)
if rule.targets:
if isinstance(result, MultipleResults):
for single_result in result.values:
machine._add_result_to_targets(
rule.targets, single_result)
else:
machine._add_result_to_targets(
rule.targets, result)
finally:
if print_steps:
# 'result' is only used if the step has target bundles.
# If it does, and the result is a 'MultipleResult',
# then 'print_step' prints a multi-variable assignment.
machine._print_step(rule, data_to_print, result)
machine.check_invariants()
cd.stop_example()
finally:
if print_steps:
report("state.teardown()")
machine.teardown()
# Use a machine digest to identify stateful tests in the example database
run_state_machine.hypothesis.inner_test._hypothesis_internal_add_digest = function_digest(
state_machine_factory)
# Copy some attributes so @seed and @reproduce_failure "just work"
run_state_machine._hypothesis_internal_use_seed = getattr(
state_machine_factory, "_hypothesis_internal_use_seed", None)
run_state_machine._hypothesis_internal_use_reproduce_failure = getattr(
state_machine_factory, "_hypothesis_internal_use_reproduce_failure",
None)
run_state_machine._hypothesis_internal_print_given_args = False
run_state_machine(state_machine_factory)
def find(
specifier, # type: SearchStrategy
condition, # type: Callable[[Any], bool]
settings=None, # type: Settings
random=None, # type: Any
database_key=None, # type: bytes
):
# type: (...) -> Any
"""Returns the minimal example from the given strategy ``specifier`` that
matches the predicate function ``condition``."""
if settings is None:
settings = Settings(max_examples=2000)
settings = Settings(settings, suppress_health_check=HealthCheck.all())
if database_key is None and settings.database is not None:
database_key = function_digest(condition)
if not isinstance(specifier, SearchStrategy):
raise InvalidArgument("Expected SearchStrategy but got %r of type %s" %
(specifier, type(specifier).__name__))
specifier.validate()
search = specifier
random = random or new_random()
successful_examples = [0]
last_data = [None]
last_repr = [None]
def template_condition(data):
with BuildContext(data):
try:
data.is_find = True
with deterministic_PRNG():
result = data.draw(search)
data.note(result)
success = condition(result)
except UnsatisfiedAssumption:
data.mark_invalid()
if success:
successful_examples[0] += 1
if settings.verbosity >= Verbosity.verbose:
if not successful_examples[0]:
report(u"Tried non-satisfying example %s" %
(nicerepr(result), ))
elif success:
if successful_examples[0] == 1:
last_repr[0] = nicerepr(result)
report(u"Found satisfying example %s" % (last_repr[0], ))
last_data[0] = data
elif (sort_key(hbytes(data.buffer)) < sort_key(
last_data[0].buffer)
) and nicerepr(result) != last_repr[0]:
last_repr[0] = nicerepr(result)
report(u"Shrunk example to %s" % (last_repr[0], ))
last_data[0] = data
if success and not data.frozen:
data.mark_interesting()
runner = ConjectureRunner(template_condition,
settings=settings,
random=random,
database_key=database_key)
runner.run()
note_engine_for_statistics(runner)
if runner.interesting_examples:
data = ConjectureData.for_buffer(
list(runner.interesting_examples.values())[0].buffer)
with BuildContext(data):
with deterministic_PRNG():
return data.draw(search)
if runner.valid_examples == 0 and (runner.exit_reason !=
ExitReason.finished):
raise Unsatisfiable("Unable to satisfy assumptions of %s." %
(get_pretty_function_description(condition), ))
raise NoSuchExample(get_pretty_function_description(condition))
def run_state_machine_as_test(state_machine_factory, settings=None):
"""Run a state machine definition as a test, either silently doing nothing
or printing a minimal breaking program and raising an exception.
state_machine_factory is anything which returns an instance of
RuleBasedStateMachine when called with no arguments - it can be a class or a
function. settings will be used to control the execution of the test.
"""
if settings is None:
try:
settings = state_machine_factory.TestCase.settings
check_type(Settings, settings,
"state_machine_factory.TestCase.settings")
except AttributeError:
settings = Settings(deadline=None,
suppress_health_check=HealthCheck.all())
check_type(Settings, settings, "settings")
@settings
@given(st.data())
def run_state_machine(factory, data):
machine = factory()
if not isinstance(machine, _GenericStateMachine):
raise InvalidArgument(
"Expected RuleBasedStateMachine but state_machine_factory() "
"returned %r (type=%s)" % (machine, type(machine).__name__))
data.conjecture_data.hypothesis_runner = machine
print_steps = (current_build_context().is_final
or current_verbosity() >= Verbosity.debug)
try:
if print_steps:
machine.print_start()
machine.check_invariants()
max_steps = settings.stateful_step_count
steps_run = 0
cd = data.conjecture_data
while True:
# We basically always want to run the maximum number of steps,
# but need to leave a small probability of terminating early
# in order to allow for reducing the number of steps once we
# find a failing test case, so we stop with probability of
# 2 ** -16 during normal operation but force a stop when we've
# generated enough steps.
cd.start_example(STATE_MACHINE_RUN_LABEL)
if steps_run == 0:
cd.draw_bits(16, forced=1)
elif steps_run >= max_steps:
cd.draw_bits(16, forced=0)
break
else:
# All we really care about is whether this value is zero
# or non-zero, so if it's > 1 we discard it and insert a
# replacement value after
cd.start_example(SHOULD_CONTINUE_LABEL)
should_continue_value = cd.draw_bits(16)
if should_continue_value > 1:
cd.stop_example(discard=True)
cd.draw_bits(16,
forced=int(bool(should_continue_value)))
else:
cd.stop_example()
if should_continue_value == 0:
break
steps_run += 1
value = data.conjecture_data.draw(machine.steps())
# Assign 'result' here in case 'execute_step' fails below
result = multiple()
try:
result = machine.execute_step(value)
finally:
if print_steps:
# 'result' is only used if the step has target bundles.
# If it does, and the result is a 'MultipleResult',
# then 'print_step' prints a multi-variable assignment.
machine.print_step(value, result)
machine.check_invariants()
data.conjecture_data.stop_example()
finally:
if print_steps:
machine.print_end()
machine.teardown()
# Use a machine digest to identify stateful tests in the example database
run_state_machine.hypothesis.inner_test._hypothesis_internal_add_digest = function_digest(
state_machine_factory)
# Copy some attributes so @seed and @reproduce_failure "just work"
run_state_machine._hypothesis_internal_use_seed = getattr(
state_machine_factory, "_hypothesis_internal_use_seed", None)
run_state_machine._hypothesis_internal_use_reproduce_failure = getattr(
state_machine_factory, "_hypothesis_internal_use_reproduce_failure",
None)
run_state_machine._hypothesis_internal_print_given_args = False
run_state_machine(state_machine_factory)
class StateMachineTestCase(TestCase):
settings = Settings(deadline=None,
suppress_health_check=HealthCheck.all())
def find(
specifier, # type: SearchStrategy
condition, # type: Callable[[Any], bool]
settings=None, # type: Settings
random=None, # type: Any
database_key=None, # type: bytes
):
# type: (...) -> Any
"""Returns the minimal example from the given strategy ``specifier`` that
matches the predicate function ``condition``."""
if settings is None:
settings = Settings(max_examples=2000)
settings = Settings(settings, suppress_health_check=HealthCheck.all())
if database_key is None and settings.database is not None:
database_key = function_digest(condition)
if not isinstance(specifier, SearchStrategy):
raise InvalidArgument(
'Expected SearchStrategy but got %r of type %s' % (
specifier, type(specifier).__name__
))
specifier.validate()
search = specifier
random = random or new_random()
successful_examples = [0]
last_data = [None]
last_repr = [None]
def template_condition(data):
with BuildContext(data):
try:
data.is_find = True
with deterministic_PRNG():
result = data.draw(search)
data.note(result)
success = condition(result)
except UnsatisfiedAssumption:
data.mark_invalid()
if success:
successful_examples[0] += 1
if settings.verbosity >= Verbosity.verbose:
if not successful_examples[0]:
report(
u'Tried non-satisfying example %s' % (nicerepr(result),))
elif success:
if successful_examples[0] == 1:
last_repr[0] = nicerepr(result)
report(u'Found satisfying example %s' % (last_repr[0],))
last_data[0] = data
elif (
sort_key(hbytes(data.buffer)) <
sort_key(last_data[0].buffer)
) and nicerepr(result) != last_repr[0]:
last_repr[0] = nicerepr(result)
report(u'Shrunk example to %s' % (last_repr[0],))
last_data[0] = data
if success and not data.frozen:
data.mark_interesting()
start = benchmark_time()
runner = ConjectureRunner(
template_condition, settings=settings, random=random,
database_key=database_key,
)
runner.run()
note_engine_for_statistics(runner)
run_time = benchmark_time() - start
if runner.interesting_examples:
data = ConjectureData.for_buffer(
list(runner.interesting_examples.values())[0].buffer)
with BuildContext(data):
with deterministic_PRNG():
return data.draw(search)
if runner.valid_examples == 0 and (
runner.exit_reason != ExitReason.finished
):
if settings.timeout > 0 and run_time > settings.timeout:
raise Timeout(( # pragma: no cover
'Ran out of time before finding enough valid examples for '
'%s. Only %d valid examples found in %.2f seconds.'
) % (
get_pretty_function_description(condition),
runner.valid_examples, run_time))
else:
raise Unsatisfiable(
'Unable to satisfy assumptions of %s.' %
(get_pretty_function_description(condition),)
)
raise NoSuchExample(get_pretty_function_description(condition))
def run_state_machine_as_test(state_machine_factory, settings=None):
"""Run a state machine definition as a test, either silently doing nothing
or printing a minimal breaking program and raising an exception.
state_machine_factory is anything which returns an instance of
GenericStateMachine when called with no arguments - it can be a class or a
function. settings will be used to control the execution of the test.
"""
if settings is None:
try:
settings = state_machine_factory.TestCase.settings
check_type(Settings, settings,
"state_machine_factory.TestCase.settings")
except AttributeError:
settings = Settings(deadline=None,
suppress_health_check=HealthCheck.all())
check_type(Settings, settings, "settings")
@settings
@given(st.data())
def run_state_machine(factory, data):
machine = factory()
if isinstance(machine, GenericStateMachine) and not isinstance(
machine, RuleBasedStateMachine):
note_deprecation(
"%s inherits from GenericStateMachine, which is deprecated. Use a "
"RuleBasedStateMachine, or a test function with st.data(), instead."
% (type(machine).__name__, ),
since="2019-05-29",
)
else:
check_type(RuleBasedStateMachine, machine,
"state_machine_factory()")
data.conjecture_data.hypothesis_runner = machine
n_steps = settings.stateful_step_count
should_continue = cu.many(data.conjecture_data,
min_size=1,
max_size=n_steps,
average_size=n_steps)
print_steps = (current_build_context().is_final
or current_verbosity() >= Verbosity.debug)
try:
if print_steps:
machine.print_start()
machine.check_invariants()
while should_continue.more():
value = data.conjecture_data.draw(machine.steps())
# Assign 'result' here in case 'execute_step' fails below
result = multiple()
try:
result = machine.execute_step(value)
finally:
if print_steps:
# 'result' is only used if the step has target bundles.
# If it does, and the result is a 'MultipleResult',
# then 'print_step' prints a multi-variable assignment.
machine.print_step(value, result)
machine.check_invariants()
finally:
if print_steps:
machine.print_end()
machine.teardown()
# Use a machine digest to identify stateful tests in the example database
run_state_machine.hypothesis.inner_test._hypothesis_internal_add_digest = function_digest(
state_machine_factory)
# Copy some attributes so @seed and @reproduce_failure "just work"
run_state_machine._hypothesis_internal_use_seed = getattr(
state_machine_factory, "_hypothesis_internal_use_seed", None)
run_state_machine._hypothesis_internal_use_reproduce_failure = getattr(
state_machine_factory, "_hypothesis_internal_use_reproduce_failure",
None)
run_state_machine._hypothesis_internal_print_given_args = False
run_state_machine(state_machine_factory)
def find(specifier, condition, settings=None, random=None, database_key=None):
"""Returns the minimal example from the given strategy ``specifier`` that
matches the predicate function ``condition``."""
settings = settings or Settings(
max_examples=2000,
max_shrinks=2000,
)
settings = Settings(settings, suppress_health_check=HealthCheck.all())
if database_key is None and settings.database is not None:
database_key = function_digest(condition)
if not isinstance(specifier, SearchStrategy):
raise InvalidArgument('Expected SearchStrategy but got %r of type %s' %
(specifier, type(specifier).__name__))
specifier.validate()
search = specifier
random = random or new_random()
successful_examples = [0]
last_data = [None]
last_repr = [None]
def template_condition(data):
with BuildContext(data):
try:
data.is_find = True
result = data.draw(search)
data.note(result)
success = condition(result)
except UnsatisfiedAssumption:
data.mark_invalid()
if success:
successful_examples[0] += 1
if settings.verbosity >= Verbosity.verbose:
if not successful_examples[0]:
report(u'Tried non-satisfying example %s' %
(nicerepr(result), ))
elif success:
if successful_examples[0] == 1:
last_repr[0] = nicerepr(result)
report(u'Found satisfying example %s' % (last_repr[0], ))
last_data[0] = data
elif (sort_key(hbytes(data.buffer)) < sort_key(
last_data[0].buffer)
) and nicerepr(result) != last_repr[0]:
last_repr[0] = nicerepr(result)
report(u'Shrunk example to %s' % (last_repr[0], ))
last_data[0] = data
if success and not data.frozen:
data.mark_interesting()
start = time.time()
runner = ConjectureRunner(
template_condition,
settings=settings,
random=random,
database_key=database_key,
)
runner.run()
note_engine_for_statistics(runner)
run_time = time.time() - start
if runner.interesting_examples:
data = ConjectureData.for_buffer(
list(runner.interesting_examples.values())[0].buffer)
with BuildContext(data):
return data.draw(search)
if runner.valid_examples == 0 and (runner.exit_reason !=
ExitReason.finished):
if settings.timeout > 0 and run_time > settings.timeout:
raise Timeout(( # pragma: no cover
'Ran out of time before finding enough valid examples for '
'%s. Only %d valid examples found in %.2f seconds.') %
(get_pretty_function_description(condition),
runner.valid_examples, run_time))
else:
raise Unsatisfiable('Unable to satisfy assumptions of %s.' %
(get_pretty_function_description(condition), ))
raise NoSuchExample(get_pretty_function_description(condition))