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How to use shrunkValue method in fast-check-monorepo

Best JavaScript code snippet using fast-check-monorepo

Arbitrary.utest.spec.ts

Source:Arbitrary.utest.spec.ts

1import { Arbitrary } from '../../../../../src/check/arbitrary/definition/Arbitrary';2import { Value } from '../../../../../src/check/arbitrary/definition/Value';3import { Stream } from '../../../../../src/stream/Stream';4import * as stubRng from '../../../stubs/generators';5import { cloneMethod, hasCloneMethod } from '../../../../../src/check/symbols';6import { Random } from '../../../../../src/random/generator/Random';7const mrngNoCall = stubRng.mutable.nocall();8describe('NextArbitrary', () => {9  describe('filter', () => {10    it('should filter the values produced by the original arbitrary on generate', () => {11      // Arrange12      const expectedBiasFactor = 48;13      const generate = jest.fn();14      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;15      const shrink = jest.fn();16      const choice1 = new Value(1, Symbol());17      const choice2 = new Value(2, Symbol());18      const choice3 = new Value(3, Symbol());19      const choice4 = new Value(4, Symbol());20      generate21        .mockReturnValueOnce(choice1)22        .mockReturnValueOnce(choice2)23        .mockReturnValueOnce(choice3)24        .mockReturnValueOnce(choice4);25      class MyNextArbitrary extends Arbitrary<any> {26        generate = generate;27        canShrinkWithoutContext = canShrinkWithoutContext;28        shrink = shrink;29      }30      // Act31      const arb = new MyNextArbitrary().filter((v) => v % 3 === 0);32      const g = arb.generate(mrngNoCall, expectedBiasFactor);33      // Assert34      expect(g).toBe(choice3); // just returning the first Value that fits35      expect(generate).toHaveBeenNthCalledWith(3, mrngNoCall, expectedBiasFactor); // same Random not cloned36    });37    it('should filter the values produced by the original arbitrary on shrink', () => {38      // Arrange39      const generate = jest.fn();40      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;41      const shrink = jest.fn();42      const valueToShrink = 5;43      const contextToShrink = Symbol();44      const choice1 = new Value(1, Symbol());45      const choice2 = new Value(2, Symbol());46      const choice3 = new Value(3, Symbol());47      const choice4 = new Value(4, Symbol());48      const choice5 = new Value(6, Symbol());49      shrink.mockReturnValueOnce(Stream.of(choice1, choice2, choice3, choice4, choice5));50      class MyNextArbitrary extends Arbitrary<any> {51        generate = generate;52        canShrinkWithoutContext = canShrinkWithoutContext;53        shrink = shrink;54      }55      // Act56      const arb = new MyNextArbitrary().filter((v) => v % 3 === 0);57      const shrinks = arb.shrink(valueToShrink, contextToShrink);58      // Assert59      expect([...shrinks]).toEqual([choice3, choice5]); // just keeping values fitting the predicate60      expect(shrink).toHaveBeenCalledWith(valueToShrink, contextToShrink);61    });62    it.each`63      canShrinkWithoutContextOutput | predicateOutput | expected64      ${false}                      | ${false}        | ${false}65      ${false}                      | ${true}         | ${false}66      ${false}                      | ${false}        | ${false}67      ${true}                       | ${true}         | ${true}68    `(69      'should check underlying arbitrary then predicate to know if the value could have been generated',70      ({ canShrinkWithoutContextOutput, predicateOutput, expected }) => {71        // Arrange72        const requestedValue = Symbol();73        const generate = jest.fn();74        const canShrinkWithoutContext = jest.fn();75        const shrink = jest.fn();76        const predicate = jest.fn();77        class MyNextArbitrary extends Arbitrary<any> {78          generate = generate;79          canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;80          shrink = shrink;81        }82        canShrinkWithoutContext.mockReturnValueOnce(canShrinkWithoutContextOutput);83        predicate.mockReturnValueOnce(predicateOutput);84        // Act85        const arb = new MyNextArbitrary().filter(predicate);86        const out = arb.canShrinkWithoutContext(requestedValue);87        // Assert88        expect(out).toBe(expected);89        expect(canShrinkWithoutContext).toHaveBeenCalledWith(requestedValue);90        if (canShrinkWithoutContextOutput) {91          expect(predicate).toHaveBeenCalledWith(requestedValue);92        } else {93          expect(predicate).not.toHaveBeenCalledWith(requestedValue);94          expect(predicate).not.toHaveBeenCalled();95        }96      }97    );98  });99  describe('map', () => {100    it('should map the values produced by the original arbitrary on generate', () => {101      // Arrange102      const expectedBiasFactor = 48;103      const generate = jest.fn();104      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;105      const shrink = jest.fn();106      const choice = new Value(1, Symbol());107      generate.mockReturnValueOnce(choice);108      class MyNextArbitrary extends Arbitrary<any> {109        generate = generate;110        canShrinkWithoutContext = canShrinkWithoutContext;111        shrink = shrink;112      }113      // Act114      const arb = new MyNextArbitrary().map((v) => String(v));115      const g = arb.generate(mrngNoCall, expectedBiasFactor);116      // Assert117      expect(g.value).toBe(String(choice.value)); // value has been mapped118      expect(generate).toHaveBeenCalledWith(mrngNoCall, expectedBiasFactor);119    });120    it('should preserve cloneable capabilities for mapped values on generate', () => {121      // Arrange122      const expectedBiasFactor = 48;123      const generate = jest.fn();124      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;125      const shrink = jest.fn();126      const choice = new Value({ source: 1, [cloneMethod]: () => choice.value_ }, Symbol());127      generate.mockReturnValueOnce(choice);128      class MyNextArbitrary extends Arbitrary<any> {129        generate = generate;130        canShrinkWithoutContext = canShrinkWithoutContext;131        shrink = shrink;132      }133      // Act134      const arb = new MyNextArbitrary().map((v) => ({ stringValue: String(v.source) }));135      const g = arb.generate(mrngNoCall, expectedBiasFactor);136      // Assert137      expect(g.value.stringValue).toBe(String(choice.value.source)); // value has been mapped138      expect(g.hasToBeCloned).toBe(true); // clone has been preserved on Value139      expect(hasCloneMethod(g.value)).toBe(true); // clone has been preserved on the instance140      expect(generate).toHaveBeenCalledWith(mrngNoCall, expectedBiasFactor);141    });142    it('should not alter the mapped value if already cloneable on generate', () => {143      // Arrange144      const expectedBiasFactor = 48;145      const generate = jest.fn();146      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;147      const shrink = jest.fn();148      const choice = new Value({ source: 1, [cloneMethod]: () => choice.value_ }, Symbol());149      const mappedClone = jest.fn();150      const mapped = { source: 42, [cloneMethod]: mappedClone };151      generate.mockReturnValueOnce(choice);152      class MyNextArbitrary extends Arbitrary<any> {153        generate = generate;154        canShrinkWithoutContext = canShrinkWithoutContext;155        shrink = shrink;156      }157      // Act158      const arb = new MyNextArbitrary().map((_v) => mapped); // mapped already comes with clone capacities159      const g = arb.generate(mrngNoCall, expectedBiasFactor);160      // Assert161      expect(g.value_).toBe(mapped); // value has been mapped162      expect(g.value_.source).toBe(mapped.source); // value has been mapped and value not altered163      expect(g.value_[cloneMethod]).toBe(mapped[cloneMethod]); // value has been mapped and clone method has been preserved164      expect(g.hasToBeCloned).toBe(true); // clone has been preserved on Value165      expect(hasCloneMethod(g.value_)).toBe(true); // clone has been preserved on the instance166      expect(generate).toHaveBeenCalledWith(mrngNoCall, expectedBiasFactor);167    });168    it('should properly shrink output of generate by calling back shrink with the right context', () => {169      // Arrange170      const expectedBiasFactor = 42;171      const generate = jest.fn();172      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;173      const shrink = jest.fn();174      const source = new Value(69, Symbol());175      generate.mockReturnValueOnce(source);176      const choice1 = new Value(1, Symbol());177      const choice2 = new Value(2, Symbol());178      const choice3 = new Value(3, Symbol());179      shrink.mockReturnValueOnce(Stream.of(choice1, choice2, choice3));180      class MyNextArbitrary extends Arbitrary<any> {181        generate = generate;182        canShrinkWithoutContext = canShrinkWithoutContext;183        shrink = shrink;184      }185      // Act186      const arb = new MyNextArbitrary().map((v) => String(v));187      const g = arb.generate(mrngNoCall, expectedBiasFactor);188      const shrinks = arb.shrink(g.value, g.context);189      // Assert190      expect([...shrinks].map((s) => s.value)).toEqual(['1', '2', '3']); // just mapping values191      expect(shrink).toHaveBeenCalledWith(source.value, source.context);192    });193    it('should properly shrink output of shrink by calling back shrink with the right context', () => {194      // Arrange195      const expectedBiasFactor = 42;196      const generate = jest.fn();197      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;198      const shrink = jest.fn();199      const source = new Value(69, Symbol());200      generate.mockReturnValueOnce(source);201      const choice1 = new Value(1, Symbol());202      const choice2 = new Value(2, Symbol());203      const choice3 = new Value(3, Symbol());204      shrink.mockReturnValueOnce(Stream.of(choice1, choice2, choice3));205      const choice21 = new Value(21, Symbol());206      const choice22 = new Value(22, Symbol());207      shrink.mockReturnValueOnce(Stream.of(choice21, choice22));208      class MyNextArbitrary extends Arbitrary<any> {209        generate = generate;210        canShrinkWithoutContext = canShrinkWithoutContext;211        shrink = shrink;212      }213      // Act214      const arb = new MyNextArbitrary().map((v) => String(v));215      const g = arb.generate(mrngNoCall, expectedBiasFactor);216      const shrinksGen1 = arb.shrink(g.value, g.context);217      const mappedChoice2 = shrinksGen1.getNthOrLast(1)!;218      const shrinksGen2 = arb.shrink(mappedChoice2.value, mappedChoice2.context);219      // Assert220      expect([...shrinksGen2].map((s) => s.value)).toEqual(['21', '22']); // just mapping values221      expect(shrink).toHaveBeenCalledWith(source.value, source.context);222      expect(shrink).toHaveBeenCalledWith(choice2.value, choice2.context);223    });224    it('should preserve cloneable capabilities for mapped values on shrink', () => {225      // Arrange226      const expectedBiasFactor = 48;227      const generate = jest.fn();228      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;229      const shrink = jest.fn();230      const source = new Value({ source: 1, [cloneMethod]: () => source.value_ }, Symbol());231      generate.mockReturnValueOnce(source);232      const choice1 = new Value({ source: 2, [cloneMethod]: () => choice1.value_ }, Symbol());233      const choice2 = new Value({ source: 2, [cloneMethod]: () => choice2.value_ }, Symbol());234      shrink.mockReturnValueOnce(Stream.of(choice1, choice2));235      class MyNextArbitrary extends Arbitrary<any> {236        generate = generate;237        canShrinkWithoutContext = canShrinkWithoutContext;238        shrink = shrink;239      }240      // Act241      const arb = new MyNextArbitrary().map((v) => ({ stringValue: String(v.source) }));242      const g = arb.generate(mrngNoCall, expectedBiasFactor);243      const shrinks = arb.shrink(g.value, g.context);244      const shrinksValues = [...shrinks];245      // Assert246      expect(shrinksValues).toHaveLength(2);247      expect(shrinksValues[0].hasToBeCloned).toBe(true); // clone has been preserved on Value248      expect(shrinksValues[1].hasToBeCloned).toBe(true);249      expect(hasCloneMethod(shrinksValues[0].value)).toBe(true); // clone has been preserved on the instance250      expect(hasCloneMethod(shrinksValues[1].value)).toBe(true);251    });252    it('should always return false for canShrinkWithoutContext when not provided any unmapper function', () => {253      // Arrange254      const generate = jest.fn();255      const canShrinkWithoutContext = jest.fn();256      const shrink = jest.fn();257      class MyNextArbitrary extends Arbitrary<any> {258        generate = generate;259        canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;260        shrink = shrink;261      }262      // Act263      const arb = new MyNextArbitrary().map(() => '');264      const out = arb.canShrinkWithoutContext('');265      // Assert266      expect(out).toBe(false);267      expect(canShrinkWithoutContext).not.toHaveBeenCalled();268    });269    it('should return empty stream when shrinking without any context and not provided any unmapper function', () => {270      // Arrange271      const generate = jest.fn();272      const canShrinkWithoutContext = jest.fn();273      const shrink = jest.fn();274      class MyNextArbitrary extends Arbitrary<any> {275        generate = generate;276        canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;277        shrink = shrink;278      }279      // Act280      const arb = new MyNextArbitrary().map(() => '');281      const shrinks = arb.shrink('', undefined);282      // Assert283      expect([...shrinks]).toHaveLength(0);284      expect(shrink).not.toHaveBeenCalled();285      expect(canShrinkWithoutContext).not.toHaveBeenCalled();286    });287    it.each`288      outputCanGenerate289      ${false}290      ${true}291    `(292      'should try to unmap the value then call source arbitrary on canShrinkWithoutContext when provided a successful unmapper function',293      ({ outputCanGenerate }) => {294        // Arrange295        const generate = jest.fn();296        const canShrinkWithoutContext = jest.fn().mockReturnValue(outputCanGenerate);297        const shrink = jest.fn();298        const originalValue = Symbol();299        const unmapperOutput = Symbol();300        const unmapper = jest.fn().mockReturnValue(unmapperOutput);301        class MyNextArbitrary extends Arbitrary<any> {302          generate = generate;303          canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;304          shrink = shrink;305        }306        // Act307        const arb = new MyNextArbitrary().map(() => Symbol(), unmapper);308        const out = arb.canShrinkWithoutContext(originalValue);309        // Assert310        expect(out).toBe(outputCanGenerate);311        expect(unmapper).toHaveBeenCalledTimes(1);312        expect(unmapper).toHaveBeenCalledWith(originalValue);313        expect(canShrinkWithoutContext).toHaveBeenCalledTimes(1);314        expect(canShrinkWithoutContext).toHaveBeenCalledWith(unmapperOutput);315      }316    );317    it('should try to unmap the value and stop on error in case of failing unmapper function', () => {318      // Arrange319      const generate = jest.fn();320      const canShrinkWithoutContext = jest.fn();321      const shrink = jest.fn();322      const originalValue = Symbol();323      const unmapper = jest.fn().mockImplementation(() => {324        throw new Error('Unable to unmap such value');325      });326      class MyNextArbitrary extends Arbitrary<any> {327        generate = generate;328        canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;329        shrink = shrink;330      }331      // Act332      const arb = new MyNextArbitrary().map(() => Symbol(), unmapper);333      const out = arb.canShrinkWithoutContext(originalValue);334      // Assert335      expect(out).toBe(false);336      expect(unmapper).toHaveBeenCalledTimes(1);337      expect(unmapper).toHaveBeenCalledWith(originalValue);338      expect(canShrinkWithoutContext).not.toHaveBeenCalled();339    });340    it('should return a mapped version of the stream produced by the source arbitrary for the unmapped value when provided an unmapper function', () => {341      // Arrange342      const expectedStreamValuesFromSource = Stream.of(343        new Value('titi', undefined),344        new Value('toto', undefined),345        new Value('tutu', undefined)346      );347      const generate = jest.fn();348      const canShrinkWithoutContext = jest.fn();349      const shrink = jest.fn().mockReturnValueOnce(expectedStreamValuesFromSource);350      const originalValue = Symbol();351      const unmapperOutput = 'tata';352      const unmapper = jest.fn().mockReturnValue('tata');353      class MyNextArbitrary extends Arbitrary<any> {354        generate = generate;355        canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;356        shrink = shrink;357      }358      // Act359      const arb = new MyNextArbitrary().map((tag) => Symbol.for(tag), unmapper);360      const shrinks = [...arb.shrink(originalValue, undefined)];361      // Assert362      expect(shrinks.map((s) => s.value)).toEqual([Symbol.for('titi'), Symbol.for('toto'), Symbol.for('tutu')]);363      expect(unmapper).toHaveBeenCalledTimes(1);364      expect(unmapper).toHaveBeenCalledWith(originalValue);365      expect(shrink).toHaveBeenCalledTimes(1);366      expect(shrink).toHaveBeenCalledWith(unmapperOutput, undefined);367    });368  });369  describe('chain', () => {370    it('should chain the values produced by the original arbitrary on generate', () => {371      // Arrange372      const expectedBiasFactor = 48;373      const generate = jest.fn();374      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;375      const shrink = jest.fn();376      const choiceRoot = new Value(1, Symbol());377      generate.mockReturnValueOnce(choiceRoot);378      const generateChained = jest.fn();379      const canShrinkWithoutContextChained = jest.fn() as any as (value: unknown) => value is any;380      const shrinkChained = jest.fn();381      const choiceChained = new Value(50, Symbol());382      generateChained.mockReturnValueOnce(choiceChained);383      class MyNextArbitrary extends Arbitrary<any> {384        generate = generate;385        canShrinkWithoutContext = canShrinkWithoutContext;386        shrink = shrink;387      }388      class MyNextChainedArbitrary extends Arbitrary<any> {389        generate = generateChained;390        canShrinkWithoutContext = canShrinkWithoutContextChained;391        shrink = shrinkChained;392      }393      const chainer = jest.fn();394      chainer.mockReturnValueOnce(new MyNextChainedArbitrary());395      // Act396      const arb = new MyNextArbitrary().chain(chainer);397      const g = arb.generate(mrngNoCall, expectedBiasFactor);398      // Assert399      expect(g.value).toBe(choiceChained.value); // value has been chained400      expect(generate).toHaveBeenCalledWith(mrngNoCall, expectedBiasFactor); // the two calls to generate401      expect(generateChained).toHaveBeenCalledWith(mrngNoCall, expectedBiasFactor); // they share the same Random402      expect(chainer).toHaveBeenCalledWith(choiceRoot.value); // chainer was called with output of generate403    });404    it('should properly shrink output of generate by calling back shrink with the right context', () => {405      // Arrange406      const expectedBiasFactor = 48;407      const generate = jest.fn();408      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;409      const shrink = jest.fn();410      const choiceRoot = new Value(1, Symbol());411      generate.mockReturnValueOnce(choiceRoot);412      const shrinkRoot1 = new Value(10, Symbol());413      const shrinkRoot2 = new Value(11, Symbol());414      const shrinkRoot3 = new Value(15, Symbol());415      shrink.mockReturnValueOnce(Stream.of(shrinkRoot1, shrinkRoot2, shrinkRoot3));416      const generateChained = jest.fn();417      const canShrinkWithoutContextChained = jest.fn() as any as (value: unknown) => value is any;418      const shrinkChained = jest.fn();419      const choiceChained = new Value(50, Symbol());420      const choiceShrink1Chained = new Value(58, Symbol()); // chain will be called for each sub-shrink of root421      const choiceShrink2Chained = new Value(57, Symbol());422      const choiceShrink3Chained = new Value(16, Symbol());423      generateChained424        .mockReturnValueOnce(choiceChained)425        .mockReturnValueOnce(choiceShrink1Chained)426        .mockReturnValueOnce(choiceShrink2Chained)427        .mockReturnValueOnce(choiceShrink3Chained);428      const shrinkChained1 = new Value(25, Symbol());429      const shrinkChained2 = new Value(51, Symbol());430      shrinkChained.mockReturnValueOnce(Stream.of(shrinkChained1, shrinkChained2));431      class MyNextArbitrary extends Arbitrary<any> {432        generate = generate;433        canShrinkWithoutContext = canShrinkWithoutContext;434        shrink = shrink;435      }436      class MyNextChainedArbitrary extends Arbitrary<any> {437        generate = generateChained;438        canShrinkWithoutContext = canShrinkWithoutContextChained;439        shrink = shrinkChained;440      }441      const chainer = jest.fn();442      chainer.mockReturnValue(new MyNextChainedArbitrary());443      // Act444      const arb = new MyNextArbitrary().chain(chainer);445      const g = arb.generate(mrngNoCall, expectedBiasFactor);446      const shrinks = arb.shrink(g.value, g.context);447      // Assert448      expect([...shrinks].map((v) => v.value)).toEqual([449        choiceShrink1Chained.value,450        choiceShrink2Chained.value,451        choiceShrink3Chained.value,452        shrinkChained1.value,453        shrinkChained2.value,454      ]); // shrink of source chained, then the one of original chained455      expect(generateChained).toHaveBeenNthCalledWith(4, expect.any(Random), expectedBiasFactor); // sub-sequent calls re-use the original bias456      expect(chainer).toHaveBeenCalledWith(choiceRoot.value); // original call457      expect(chainer).toHaveBeenCalledWith(shrinkRoot1.value); // chained during shrink458      expect(chainer).toHaveBeenCalledWith(shrinkRoot2.value); // chained during shrink459      expect(chainer).toHaveBeenCalledWith(shrinkRoot3.value); // chained during shrink460    });461    it('should properly shrink output of shrink by calling back shrink with the right context', () => {462      // Arrange463      const expectedBiasFactor = 48;464      const generate = jest.fn();465      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;466      const shrink = jest.fn();467      const choiceRoot = new Value(1, Symbol());468      generate.mockReturnValueOnce(choiceRoot);469      const shrinkRoot1 = new Value(10, Symbol());470      const shrinkRoot2 = new Value(11, Symbol()); // will not be iterated (getNthOrLast(0))471      const shrinkRoot3 = new Value(15, Symbol()); // will not be iterated (getNthOrLast(0))472      shrink.mockReturnValueOnce(Stream.of(shrinkRoot1, shrinkRoot2, shrinkRoot3));473      const shrinkRoot11 = new Value(310, Symbol());474      shrink.mockReturnValueOnce(Stream.of(shrinkRoot11));475      const generateChained = jest.fn();476      const canShrinkWithoutContextChained = jest.fn() as any as (value: unknown) => value is any;477      const shrinkChained = jest.fn();478      const choiceChained = new Value(50, Symbol());479      const choiceShrink1Chained = new Value(58, Symbol()); // chain will be called for each iterated sub-shrink of root (->10)480      const choiceShrink2Chained = new Value(57, Symbol()); // ->310 - 11 and 15 will not be retrieved (getNthOrLast(0))481      generateChained482        .mockReturnValueOnce(choiceChained)483        .mockReturnValueOnce(choiceShrink1Chained)484        .mockReturnValueOnce(choiceShrink2Chained);485      const shrinkChained1 = new Value(25, Symbol());486      const shrinkChained2 = new Value(51, Symbol());487      shrinkChained.mockReturnValueOnce(Stream.of(shrinkChained1, shrinkChained2));488      const shrinkChained11 = new Value(125, Symbol());489      const shrinkChained12 = new Value(151, Symbol());490      shrinkChained.mockReturnValueOnce(Stream.of(shrinkChained11, shrinkChained12));491      class MyNextArbitrary extends Arbitrary<any> {492        generate = generate;493        canShrinkWithoutContext = canShrinkWithoutContext;494        shrink = shrink;495      }496      class MyNextChainedArbitrary extends Arbitrary<any> {497        generate = generateChained;498        canShrinkWithoutContext = canShrinkWithoutContextChained;499        shrink = shrinkChained;500      }501      const chainer = jest.fn();502      chainer.mockReturnValue(new MyNextChainedArbitrary());503      // Act504      const arb = new MyNextArbitrary().chain(chainer);505      const g = arb.generate(mrngNoCall, expectedBiasFactor);506      const firstShrunkValue = arb.shrink(g.value, g.context).getNthOrLast(0)!;507      const shrinks = arb.shrink(firstShrunkValue.value, firstShrunkValue.context);508      // Assert509      expect([...shrinks].map((v) => v.value)).toEqual([510        choiceShrink2Chained.value,511        shrinkChained11.value,512        shrinkChained12.value,513      ]);514      expect(generateChained).toHaveBeenNthCalledWith(2, expect.any(Random), expectedBiasFactor); // sub-sequent calls re-use the original bias515      expect(chainer).toHaveBeenCalledWith(choiceRoot.value); // original call516      expect(chainer).toHaveBeenCalledWith(shrinkRoot1.value); // chained during shrink517      expect(chainer).not.toHaveBeenCalledWith(shrinkRoot2.value); // chained during shrink (skipped due to getNthOrLast(0)518      expect(chainer).not.toHaveBeenCalledWith(shrinkRoot3.value); // chained during shrink (skipped due to getNthOrLast(0)519      expect(chainer).toHaveBeenCalledWith(shrinkRoot11.value); // chained during second shrink (returned choiceShrink2Chained)520    });521    it('should stop shrink on source if it exhausted it once', () => {522      // Arrange523      const expectedBiasFactor = 48;524      const generate = jest.fn();525      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;526      const shrink = jest.fn();527      const choiceRoot = new Value(1, Symbol());528      generate.mockReturnValueOnce(choiceRoot);529      const shrinkRoot1 = new Value(10, Symbol());530      const shrinkRoot2 = new Value(11, Symbol());531      shrink.mockReturnValueOnce(Stream.of(shrinkRoot1, shrinkRoot2));532      const generateChained = jest.fn();533      const canShrinkWithoutContextChained = jest.fn() as any as (value: unknown) => value is any;534      const shrinkChained = jest.fn();535      const choiceChained = new Value(50, Symbol());536      const choiceShrink1Chained = new Value(58, Symbol());537      const choiceShrink2Chained = new Value(57, Symbol());538      generateChained539        .mockReturnValueOnce(choiceChained)540        .mockReturnValueOnce(choiceShrink1Chained)541        .mockReturnValueOnce(choiceShrink2Chained);542      const shrinkChained1 = new Value(25, Symbol());543      const shrinkChained2 = new Value(51, Symbol());544      shrinkChained.mockReturnValueOnce(Stream.of(shrinkChained1, shrinkChained2));545      const shrinkChained11 = new Value(125, Symbol());546      const shrinkChained12 = new Value(151, Symbol());547      shrinkChained.mockReturnValueOnce(Stream.of(shrinkChained11, shrinkChained12));548      class MyNextArbitrary extends Arbitrary<any> {549        generate = generate;550        canShrinkWithoutContext = canShrinkWithoutContext;551        shrink = shrink;552      }553      class MyNextChainedArbitrary extends Arbitrary<any> {554        generate = generateChained;555        canShrinkWithoutContext = canShrinkWithoutContextChained;556        shrink = shrinkChained;557      }558      const chainer = jest.fn();559      chainer.mockReturnValue(new MyNextChainedArbitrary());560      // Act561      const arb = new MyNextArbitrary().chain(chainer);562      const g = arb.generate(mrngNoCall, expectedBiasFactor);563      const shrunkValue = arb.shrink(g.value, g.context).getNthOrLast(2)!; // source will be exhausted it only declares two shrunk values564      const shrinks = arb.shrink(shrunkValue.value, shrunkValue.context);565      // Assert566      expect([...shrinks].map((v) => v.value)).toEqual([shrinkChained11.value, shrinkChained12.value]);567      expect(shrink).toHaveBeenCalledTimes(1); // not called back on second call to shrink568    });569    it('should always return false for canShrinkWithoutContext when not provided any unchain function', () => {570      // Arrange571      const generate = jest.fn();572      const canShrinkWithoutContext = jest.fn();573      const shrink = jest.fn();574      class MyNextArbitrary extends Arbitrary<any> {575        generate = generate;576        canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;577        shrink = shrink;578      }579      // Act580      const arb = new MyNextArbitrary().chain(() => new MyNextArbitrary());581      const out = arb.canShrinkWithoutContext('');582      // Assert583      expect(out).toBe(false);584      expect(canShrinkWithoutContext).not.toHaveBeenCalled();585    });586    it('should return empty stream when shrinking without any context and not provided any unchainer function', () => {587      // Arrange588      const generate = jest.fn();589      const canShrinkWithoutContext = jest.fn();590      const shrink = jest.fn();591      class MyNextArbitrary extends Arbitrary<any> {592        generate = generate;593        canShrinkWithoutContext = canShrinkWithoutContext as any as (value: unknown) => value is any;594        shrink = shrink;595      }596      // Act597      const arb = new MyNextArbitrary().chain(() => new MyNextArbitrary());598      const shrinks = arb.shrink('', undefined);599      // Assert600      expect([...shrinks]).toHaveLength(0);601      expect(shrink).not.toHaveBeenCalled();602    });603  });604  describe('noShrink', () => {605    it('should simply return the original instance of Value on generate', () => {606      // Arrange607      const expectedBiasFactor = 48;608      const generate = jest.fn();609      const canShrinkWithoutContext = jest.fn() as any as (value: unknown) => value is any;610      const shrink = jest.fn();611      const choice = new Value(1, Symbol());612      generate.mockReturnValueOnce(choice);613      class MyNextArbitrary extends Arbitrary<any> {614        generate = generate;615        canShrinkWithoutContext = canShrinkWithoutContext;616        shrink = shrink;617      }618      // Act619      const arb = new MyNextArbitrary().noShrink();620      const g = arb.generate(mrngNoCall, expectedBiasFactor);621      // Assert622      expect(g).toBe(choice); // just returning the instance of the source arbitrary (including its context)623      expect(generate).toHaveBeenCalledWith(mrngNoCall, expectedBiasFactor);624    });625    it('should override default shrink with function returning an empty Stream', () => {626      // Arrange627      const shrink = jest.fn();628      class MyNextArbitrary extends Arbitrary<any> {629        generate(): Value<any> {630          throw new Error('Not implemented.');631        }632        canShrinkWithoutContext(value: unknown): value is any {633          throw new Error('Not implemented.');634        }635        shrink = shrink;636      }637      const fakeArbitrary: Arbitrary<any> = new MyNextArbitrary();638      const noShrinkArbitrary = fakeArbitrary.noShrink();639      // Act640      const out = noShrinkArbitrary.shrink(5, Symbol());641      // Assert642      expect([...out]).toHaveLength(0);643      expect(shrink).not.toHaveBeenCalled();644    });645    it('should return itself when called twice', () => {646      // Arrange647      class MyNextArbitrary extends Arbitrary<any> {648        generate(): Value<any> {649          throw new Error('Not implemented.');650        }651        canShrinkWithoutContext(value: unknown): value is any {652          throw new Error('Not implemented.');653        }654        shrink(): Stream<Value<any>> {655          throw new Error('Not implemented.');656        }657      }658      const fakeArbitrary: Arbitrary<any> = new MyNextArbitrary();659      // Act660      const firstNoShrink = fakeArbitrary.noShrink();661      const secondNoShrink = firstNoShrink.noShrink();662      // Assert663      expect(secondNoShrink).toBe(firstNoShrink);664    });665  });666  describe('noBias', () => {667    it('should override passed bias with undefined', () => {668      // Arrange669      const generate = jest.fn();670      class MyNextArbitrary extends Arbitrary<any> {671        generate = generate;672        canShrinkWithoutContext(value: unknown): value is any {673          throw new Error('Not implemented.');674        }675        shrink(): Stream<Value<any>> {676          throw new Error('Not implemented.');677        }678      }679      const fakeArbitrary: Arbitrary<any> = new MyNextArbitrary();680      const noBiasArbitrary = fakeArbitrary.noBias();681      // Act682      noBiasArbitrary.generate(mrngNoCall, 42);683      // Assert684      expect(generate).toHaveBeenCalledTimes(1);685      expect(generate).toHaveBeenCalledWith(mrngNoCall, undefined);686    });687    it('should return itself when called twice', () => {688      // Arrange689      class MyNextArbitrary extends Arbitrary<any> {690        generate(): Value<any> {691          throw new Error('Not implemented.');692        }693        canShrinkWithoutContext(value: unknown): value is any {694          throw new Error('Not implemented.');695        }696        shrink(): Stream<Value<any>> {697          throw new Error('Not implemented.');698        }699      }700      const fakeArbitrary: Arbitrary<any> = new MyNextArbitrary();701      // Act702      const firstNoBias = fakeArbitrary.noBias();703      const secondNoBias = firstNoBias.noBias();704      // Assert705      expect(secondNoBias).toBe(firstNoBias);706    });707  });...

04.js

Source:04.js

1/* Question 04 (stretch)2This is a STRETCH QUESTION.3Given a size in bits convert it to relevant size in B/KB/MB/GB/TB. Round your answers to two decimal places at most. Use base 10 for sizes.4- 1 B5- 1 kB == 1000 B6- 1 MB == 1000 kB7- 1 GB == 1000 MB8- 1 TB == 1000 GB9More info on these in case you are curious:10https://en.wikipedia.org/wiki/Byte#Unit_symbol11Examples:12- filesize(1)        => "1B"13- filesize(1000)     => "1kB"14- filesize(1000000)  => "1MB"15- filesize(1500000)  => "1.5MB"16- filesize(1250000000) => "1.25GB"17- filesize(9000000000000) => "9TB"18*/19// 1 B20// 10 B21// 100 B22// 1000 kB23const units = ["B", "B", "B", "kB", "kB", "kB", "MB", "MB", "MB"];24const someSize = 123456;25const length = String(someSize).length;26const chosenUnit = units[length - 1];27const shrunkSize = someSize / 10 ** (length - 1);28const roundedShrunkSize = Math.round(shrunkSize * 100) / 100;29console.log(length, chosenUnit, shrunkSize, roundedShrunkSize);30const shrinkAndRound = (value) => {31  const length = String(value).length;32  const shrunkValue = value / 10 ** (length - 1);33  return Math.round(shrunkValue * 100) / 100;34};35const fileSize = (size) => {36  if (size < 1000) {37    const unit = "B";38    return shrinkAndRound(size) + unit;39  }40  if (size < 1000000) {41    const unit = "kB";42    return shrinkAndRound(size) + unit;43  }44  if (size < 1000000000) {45    const unit = "MB";46    return shrinkAndRound(size) + unit;47  }48  if (size < 1000000000000) {49    const unit = "GB";50    return shrinkAndRound(size) + unit;51  }52  if (size < 1000000000000000) {53    const unit = "TB";54    return shrinkAndRound(size) + unit;55  }56};57const betterFileSizeMaybeQuestionMark = (originalSize) => {58  const unitList = [];59  for (unit of ["B", "kB", "MB", "GB", "TB"]) {60    unitList.push(unit);61    unitList.push(unit);62    unitList.push(unit);63  }64  let size = originalSize;65  let howManyTimes = 0;66  while (size > 1) {67    size = size / 10;68    howManyTimes++;69  }70  console.log(size, howManyTimes, originalSize, unitList);71  return size * 10 + unitList[howManyTimes - 1];72};73const result = betterFileSizeMaybeQuestionMark(123456);...

Using AI Code Generation

1import { shrunkValue } from 'fast-check';2import { shrunkValue } from 'fast-check-monorepo';3import { shrunkValue } from 'fast-check-monorepo/lib/types';4import { shrunkValue } from 'fast-check-monorepo/types';5import { shrunkValue } from 'fast-check-monorepo/types/lib';6import { shrunkValue } from 'fast-check-monorepo/types/lib/types';7import { shrunkValue } from 'fast-check-monorepo/types/types';8import { shrunkValue } from 'fast-check-monorepo/types/types/lib';9import { shrunkValue } from 'fast-check-monorepo/types/types/lib/types';10import { shrunkValue } from 'fast-check-monorepo/types/types/types';11import { shrunkValue } from 'fast-check-monorepo/types/types/types/lib';12import { shrunkValue } from 'fast-check-monorepo/types/types/types/lib/types';13import { shrunkValue } from 'fast-check-monorepo/types/types/types/types';14import { shrunkValue } from 'fast-check-monorepo/types/types/types/types/lib';15import { shrunkValue } from 'fast-check-monorepo/types/types/types/types/lib/types';16import { shrunkValue } from 'fast-check-monorepo/types/types/types/types/types';17import { shrunkValue } from 'fast-check-monorepo/types/types/types/types/types/lib';18import { shrunkValue } from 'fast-check-monorepo/types/types/types/types/types/lib/types';19import { shrunkValue } from 'fast-check-monorepo/types/types/types/types/types/types';20shrunkValue(42

Using AI Code Generation

1import { shrunkValue } from 'fast-check';2const shrunkValue = require('fast-check').shrunkValue;3import { fc } from 'fast-check';4const fc = require('fast-check');5import { fc } from 'fast-check';6const fc = require('fast-check');

Using AI Code Generation

1const fc = require('fast-check')2const value = fc.character().shrinkableFor('a').value3console.log(value)4const fc = require('fast-check')5const value = fc.character().shrinkableFor('a').shrink().value6console.log(value)7const fc = require('fast-check')8const value = fc.character().shrinkableFor('a').shrink().shrink().value9console.log(value)10const fc = require('fast-check')11const value = fc.character().shrinkableFor('a').shrink().shrink().shrink().value12console.log(value)13const fc = require('fast-check')14const value = fc.character().shrinkableFor('a').shrink().shrink().shrink().shrink().value15console.log(value)16const fc = require('fast-check')17const value = fc.character().shrinkableFor('a').shrink().shrink().shrink().shrink().shrink().value18console.log(value)19const fc = require('fast-check')20const value = fc.character().shrinkableFor('a').shrink().shrink().shrink().shrink().shrink().shrink().value21console.log(value)

Using AI Code Generation

1const {shrunkValue} = require('fast-check');2const value = shrunkValue(10, 0.5);3console.log(value);4const {shrunkValue} = require('fast-check/lib/check/arbitrary/definition/ShrunkValue');5const value = shrunkValue(10, 0.5);6console.log(value);

Using AI Code Generation

1const { shrunkValue } = require('fast-check')2const { create } = require('fast-check-monorepo')3const arb = create({4})5console.log(shrunkValue(arb))6{7  "dependencies": {8  }9}

Using AI Code Generation

1import * as fc from 'fast-check';2const unicodeChar = '🚀';3const unicodeCharString = unicodeChar.repeat(10);4const unicodeCharArb = fc.stringOf(fc.char(unicodeChar));5fc.assert(6  fc.property(unicodeCharArb, (unicodeCharString) => {7    const shrunkValue = fc.shrink(unicodeCharArb, unicodeCharString)8    return shrunkValue.includes(unicodeCharString);9  })10);

Automation Testing Tutorials

Learn to execute automation testing from scratch with LambdaTest Learning Hub. Right from setting up the prerequisites to run your first automation test, to following best practices and diving deeper into advanced test scenarios. LambdaTest Learning Hubs compile a list of step-by-step guides to help you be proficient with different test automation frameworks i.e. Selenium, Cypress, TestNG etc.