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How to use lower_blocks_together method in hypothesis

Best Python code snippet using hypothesis

shrinker.py

Source:shrinker.py

...945                return False946            return self.consider_new_buffer(attempt)947        find_integer(boost)948    @defines_shrink_pass()949    def lower_blocks_together(self, chooser):950        block = chooser.choose(self.blocks, lambda b: not b.all_zero)951        # Choose the next block to be up to eight blocks onwards. We don't952        # want to go too far (to avoid quadratic time) but it's worth a953        # reasonable amount of lookahead, especially as we expect most954        # blocks are zero by this point anyway.955        next_block = self.blocks[956            chooser.choose(957                range(block.index + 1, min(len(self.blocks), block.index + 9)),958                lambda j: not self.blocks[j].all_zero,959            )960        ]961        buffer = self.buffer962        m = int_from_bytes(buffer[block.start : block.end])963        n = int_from_bytes(buffer[next_block.start : next_block.end])...

test_shrinker.py

Source:test_shrinker.py

1# This file is part of Hypothesis, which may be found at2# https://github.com/HypothesisWorks/hypothesis/3#4# Most of this work is copyright (C) 2013-2020 David R. MacIver5# (david@drmaciver.com), but it contains contributions by others. See6# CONTRIBUTING.rst for a full list of people who may hold copyright, and7# consult the git log if you need to determine who owns an individual8# contribution.9#10# This Source Code Form is subject to the terms of the Mozilla Public License,11# v. 2.0. If a copy of the MPL was not distributed with this file, You can12# obtain one at https://mozilla.org/MPL/2.0/.13#14# END HEADER15import time16import pytest17from hypothesis.internal.compat import int_to_bytes18from hypothesis.internal.conjecture import floats as flt19from hypothesis.internal.conjecture.engine import ConjectureRunner20from hypothesis.internal.conjecture.shrinker import (21    Shrinker,22    ShrinkPass,23    StopShrinking,24    block_program,25)26from hypothesis.internal.conjecture.shrinking import Float27from hypothesis.internal.conjecture.utils import Sampler28from tests.conjecture.common import SOME_LABEL, run_to_buffer, shrinking_from29@pytest.mark.parametrize("n", [1, 5, 8, 15])30def test_can_shrink_variable_draws_with_just_deletion(n, monkeypatch):31    @shrinking_from([n] + [0] * (n - 1) + [1])32    def shrinker(data):33        n = data.draw_bits(4)34        b = [data.draw_bits(8) for _ in range(n)]35        if any(b):36            data.mark_interesting()37    shrinker.fixate_shrink_passes(["minimize_individual_blocks"])38    assert list(shrinker.shrink_target.buffer) == [1, 1]39def test_deletion_and_lowering_fails_to_shrink(monkeypatch):40    monkeypatch.setattr(41        Shrinker,42        "shrink",43        lambda self: self.fixate_shrink_passes(["minimize_individual_blocks"]),44    )45    def gen(self):46        self.cached_test_function(10)47    monkeypatch.setattr(ConjectureRunner, "generate_new_examples", gen)48    @run_to_buffer49    def x(data):50        for _ in range(10):51            data.draw_bytes(1)52        data.mark_interesting()53    assert x == bytes(10)54def test_duplicate_blocks_that_go_away():55    @shrinking_from([1, 1, 1, 2] * 2 + [5] * 2)56    def shrinker(data):57        x = data.draw_bits(32)58        y = data.draw_bits(32)59        if x != y:60            data.mark_invalid()61        b = [data.draw_bytes(1) for _ in range(x & 255)]62        if len(set(b)) <= 1:63            data.mark_interesting()64    shrinker.fixate_shrink_passes(["minimize_duplicated_blocks"])65    assert shrinker.shrink_target.buffer == bytes(8)66def test_accidental_duplication(monkeypatch):67    @shrinking_from([18] * 20)68    def shrinker(data):69        x = data.draw_bits(8)70        y = data.draw_bits(8)71        if x != y:72            data.mark_invalid()73        if x < 5:74            data.mark_invalid()75        b = [data.draw_bytes(1) for _ in range(x)]76        if len(set(b)) == 1:77            data.mark_interesting()78    shrinker.fixate_shrink_passes(["minimize_duplicated_blocks"])79    assert list(shrinker.buffer) == [5] * 780def test_can_zero_subintervals(monkeypatch):81    @shrinking_from(bytes([3, 0, 0, 0, 1]) * 10)82    def shrinker(data):83        for _ in range(10):84            data.start_example(SOME_LABEL)85            n = data.draw_bits(8)86            data.draw_bytes(n)87            data.stop_example()88            if data.draw_bits(8) != 1:89                return90        data.mark_interesting()91    shrinker.shrink()92    assert list(shrinker.buffer) == [0, 1] * 1093def test_can_pass_to_an_indirect_descendant(monkeypatch):94    def tree(data):95        data.start_example(1)96        n = data.draw_bits(1)97        label = data.draw_bits(8)98        if n:99            tree(data)100            tree(data)101        data.stop_example(1)102        return label103    initial = bytes([1, 10, 0, 0, 1, 0, 0, 10, 0, 0])104    target = bytes([0, 10])105    good = {initial, target}106    @shrinking_from(initial)107    def shrinker(data):108        tree(data)109        if bytes(data.buffer) in good:110            data.mark_interesting()111    shrinker.fixate_shrink_passes(["pass_to_descendant"])112    assert shrinker.shrink_target.buffer == target113def shrink(buffer, *passes):114    def accept(f):115        shrinker = shrinking_from(buffer)(f)116        shrinker.fixate_shrink_passes(passes)117        return list(shrinker.buffer)118    return accept119def test_shrinking_blocks_from_common_offset():120    @shrinking_from([11, 10])121    def shrinker(data):122        m = data.draw_bits(8)123        n = data.draw_bits(8)124        if abs(m - n) <= 1 and max(m, n) > 0:125            data.mark_interesting()126    shrinker.mark_changed(0)127    shrinker.mark_changed(1)128    shrinker.lower_common_block_offset()129    x = shrinker.shrink_target.buffer130    assert sorted(x) == [0, 1]131def test_handle_empty_draws():132    @run_to_buffer133    def x(data):134        while True:135            data.start_example(SOME_LABEL)136            n = data.draw_bits(1)137            data.start_example(SOME_LABEL)138            data.stop_example()139            data.stop_example(discard=n > 0)140            if not n:141                break142        data.mark_interesting()143    assert x == bytes([0])144def test_can_reorder_examples():145    @shrinking_from([1, 0, 1, 1, 0, 1, 0, 0, 0])146    def shrinker(data):147        total = 0148        for _ in range(5):149            data.start_example(0)150            if data.draw_bits(8):151                total += data.draw_bits(9)152            data.stop_example(0)153        if total == 2:154            data.mark_interesting()155    shrinker.fixate_shrink_passes(["reorder_examples"])156    assert list(shrinker.buffer) == [0, 0, 0, 1, 0, 1, 1, 0, 1]157def test_permits_but_ignores_raising_order(monkeypatch):158    monkeypatch.setattr(159        ConjectureRunner,160        "generate_new_examples",161        lambda runner: runner.cached_test_function([1]),162    )163    monkeypatch.setattr(164        Shrinker, "shrink", lambda self: self.incorporate_new_buffer(bytes([2]))165    )166    @run_to_buffer167    def x(data):168        data.draw_bits(2)169        data.mark_interesting()170    assert list(x) == [1]171def test_block_deletion_can_delete_short_ranges(monkeypatch):172    @shrinking_from([v for i in range(5) for _ in range(i + 1) for v in [0, i]])173    def shrinker(data):174        while True:175            n = data.draw_bits(16)176            for _ in range(n):177                if data.draw_bits(16) != n:178                    data.mark_invalid()179            if n == 4:180                data.mark_interesting()181    shrinker.fixate_shrink_passes([block_program("X" * i) for i in range(1, 5)])182    assert list(shrinker.shrink_target.buffer) == [0, 4] * 5183def test_try_shrinking_blocks_ignores_overrun_blocks(monkeypatch):184    monkeypatch.setattr(185        ConjectureRunner,186        "generate_new_examples",187        lambda runner: runner.cached_test_function([3, 3, 0, 1]),188    )189    monkeypatch.setattr(190        Shrinker,191        "shrink",192        lambda self: self.try_shrinking_blocks((0, 1, 5), bytes([2])),193    )194    @run_to_buffer195    def x(data):196        n1 = data.draw_bits(8)197        data.draw_bits(8)198        if n1 == 3:199            data.draw_bits(8)200        k = data.draw_bits(8)201        if k == 1:202            data.mark_interesting()203    assert list(x) == [2, 2, 1]204def test_dependent_block_pairs_is_up_to_shrinking_integers():205    # Unit test extracted from a failure in tests/nocover/test_integers.py206    distribution = Sampler([4.0, 8.0, 1.0, 1.0, 0.5])207    sizes = [8, 16, 32, 64, 128]208    @shrinking_from(b"\x03\x01\x00\x00\x00\x00\x00\x01\x00\x02\x01")209    def shrinker(data):210        size = sizes[distribution.sample(data)]211        result = data.draw_bits(size)212        sign = (-1) ** (result & 1)213        result = (result >> 1) * sign214        cap = data.draw_bits(8)215        if result >= 32768 and cap == 1:216            data.mark_interesting()217    shrinker.fixate_shrink_passes(["minimize_individual_blocks"])218    assert list(shrinker.shrink_target.buffer) == [1, 1, 0, 1, 0, 0, 1]219def test_finding_a_minimal_balanced_binary_tree():220    # Tests iteration while the shape of the thing being iterated over can221    # change. In particular the current example can go from trivial to non222    # trivial.223    def tree(data):224        # Returns height of a binary tree and whether it is height balanced.225        data.start_example("tree")226        n = data.draw_bits(1)227        if n == 0:228            result = (1, True)229        else:230            h1, b1 = tree(data)231            h2, b2 = tree(data)232            result = (1 + max(h1, h2), b1 and b2 and abs(h1 - h2) <= 1)233        data.stop_example("tree")234        return result235    # Starting from an unbalanced tree of depth six236    @shrinking_from([1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0])237    def shrinker(data):238        _, b = tree(data)239        if not b:240            data.mark_interesting()241    shrinker.shrink()242    assert list(shrinker.shrink_target.buffer) == [1, 0, 1, 0, 1, 0, 0]243def test_float_shrink_can_run_when_canonicalisation_does_not_work(monkeypatch):244    # This should be an error when called245    monkeypatch.setattr(Float, "shrink", None)246    base_buf = int_to_bytes(flt.base_float_to_lex(1000.0), 8) + bytes(1)247    @shrinking_from(base_buf)248    def shrinker(data):249        flt.draw_float(data)250        if bytes(data.buffer) == base_buf:251            data.mark_interesting()252    shrinker.fixate_shrink_passes(["minimize_floats"])253    assert shrinker.shrink_target.buffer == base_buf254def test_try_shrinking_blocks_out_of_bounds():255    @shrinking_from(bytes([1]))256    def shrinker(data):257        data.draw_bits(1)258        data.mark_interesting()259    assert not shrinker.try_shrinking_blocks((1,), bytes([1]))260def test_block_programs_are_adaptive():261    @shrinking_from(bytes(1000) + bytes([1]))262    def shrinker(data):263        while not data.draw_bits(1):264            pass265        data.mark_interesting()266    p = shrinker.add_new_pass(block_program("X"))267    shrinker.fixate_shrink_passes([p.name])268    assert len(shrinker.shrink_target.buffer) == 1269    assert shrinker.calls <= 60270def test_zero_examples_with_variable_min_size():271    @shrinking_from(bytes([255]) * 100)272    def shrinker(data):273        any_nonzero = False274        for i in range(1, 10):275            any_nonzero |= data.draw_bits(i * 8) > 0276        if not any_nonzero:277            data.mark_invalid()278        data.mark_interesting()279    shrinker.shrink()280    assert len([d for d in shrinker.shrink_target.blocks if not d.all_zero]) == 1281def test_zero_contained_examples():282    @shrinking_from(bytes([1]) * 8)283    def shrinker(data):284        for _ in range(4):285            data.start_example(1)286            if data.draw_bits(8) == 0:287                data.mark_invalid()288            data.start_example(1)289            data.draw_bits(8)290            data.stop_example()291            data.stop_example()292        data.mark_interesting()293    shrinker.shrink()294    assert list(shrinker.shrink_target.buffer) == [1, 0] * 4295def test_zig_zags_quickly():296    @shrinking_from(bytes([255]) * 4)297    def shrinker(data):298        m = data.draw_bits(16)299        n = data.draw_bits(16)300        if m == 0 or n == 0:301            data.mark_invalid()302        if abs(m - n) <= 1:303            data.mark_interesting(0)304        # Two different interesting origins for avoiding slipping in the305        # shrinker.306        if abs(m - n) <= 10:307            data.mark_interesting(1)308    shrinker.fixate_shrink_passes(["minimize_individual_blocks"])309    assert shrinker.engine.valid_examples <= 100310    assert list(shrinker.shrink_target.buffer) == [0, 1, 0, 1]311def test_zero_irregular_examples():312    @shrinking_from([255] * 6)313    def shrinker(data):314        data.start_example(1)315        data.draw_bits(8)316        data.draw_bits(16)317        data.stop_example()318        data.start_example(1)319        interesting = data.draw_bits(8) > 0 and data.draw_bits(16) > 0320        data.stop_example()321        if interesting:322            data.mark_interesting()323    shrinker.shrink()324    assert list(shrinker.shrink_target.buffer) == [0] * 3 + [1, 0, 1]325def test_retain_end_of_buffer():326    @shrinking_from([1, 2, 3, 4, 5, 6, 0])327    def shrinker(data):328        interesting = False329        while True:330            n = data.draw_bits(8)331            if n == 6:332                interesting = True333            if n == 0:334                break335        if interesting:336            data.mark_interesting()337    shrinker.shrink()338    assert list(shrinker.buffer) == [6, 0]339def test_can_expand_zeroed_region():340    @shrinking_from([255] * 5)341    def shrinker(data):342        seen_non_zero = False343        for _ in range(5):344            if data.draw_bits(8) == 0:345                if seen_non_zero:346                    data.mark_invalid()347            else:348                seen_non_zero = True349        data.mark_interesting()350    shrinker.shrink()351    assert list(shrinker.shrink_target.buffer) == [0] * 5352def test_can_expand_deleted_region():353    @shrinking_from([1, 2, 3, 4, 0, 0])354    def shrinker(data):355        def t():356            data.start_example(1)357            data.start_example(1)358            m = data.draw_bits(8)359            data.stop_example()360            data.start_example(1)361            n = data.draw_bits(8)362            data.stop_example()363            data.stop_example()364            return (m, n)365        v1 = t()366        if v1 == (1, 2):367            if t() != (3, 4):368                data.mark_invalid()369        if v1 == (0, 0) or t() == (0, 0):370            data.mark_interesting()371    shrinker.shrink()372    assert list(shrinker.buffer) == [0, 0]373def test_shrink_pass_method_is_idempotent():374    @shrinking_from([255])375    def shrinker(data):376        data.draw_bits(8)377        data.mark_interesting()378    sp = shrinker.shrink_pass(block_program("X"))379    assert isinstance(sp, ShrinkPass)380    assert shrinker.shrink_pass(sp) is sp381def test_will_terminate_stalled_shrinks():382    # Suppress the time based slow shrinking check - we only want383    # the one that checks if we're in a stall where we've shrunk384    # as far as we're going to get.385    time.freeze()386    @shrinking_from([255] * 100)387    def shrinker(data):388        count = 0389        for _ in range(100):390            if data.draw_bits(8) != 255:391                count += 1392                if count >= 10:393                    return394        data.mark_interesting()395    shrinker.shrink()396    assert shrinker.calls <= 1 + 2 * shrinker.max_stall397def test_will_let_fixate_shrink_passes_do_a_full_run_through():398    @shrinking_from(range(50))399    def shrinker(data):400        for i in range(50):401            if data.draw_bits(8) != i:402                data.mark_invalid()403        data.mark_interesting()404    shrinker.max_stall = 5405    passes = [block_program("X" * i) for i in range(1, 11)]406    with pytest.raises(StopShrinking):407        shrinker.fixate_shrink_passes(passes)408    assert shrinker.shrink_pass(passes[-1]).calls > 0409@pytest.mark.parametrize("n_gap", [0, 1, 2, 3])410def test_can_simultaneously_lower_non_duplicated_nearby_blocks(n_gap):411    @shrinking_from([1, 1] + [0] * n_gap + [0, 2])412    def shrinker(data):413        # Block off lowering the whole buffer414        if data.draw_bits(1) == 0:415            data.mark_invalid()416        m = data.draw_bits(8)417        for _ in range(n_gap):418            data.draw_bits(8)419        n = data.draw_bits(16)420        if n == m + 1:421            data.mark_interesting()422    shrinker.fixate_shrink_passes(["lower_blocks_together"])...

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