preserves/implementations/javascript/test/codec.test.ts

import {
    Value,
    Dictionary,
    decode, decodeWithAnnotations, encodeWithAnnotations,
    isDecodeError, isShortPacket,
    Bytes, Record,
    annotate,
    strip, peel,
    preserves,
} from '../src/index';
import './test-utils';

import * as fs from 'fs';

const Discard = Record.makeConstructor('discard', []);
const Capture = Record.makeConstructor('capture', ['pattern']);
const Observe = Record.makeConstructor('observe', ['pattern']);

describe('record constructors', () => {
    it('should have constructorInfo', () => {
        expect(Discard.constructorInfo.label).toEqual(Symbol.for('discard'));
        expect(Capture.constructorInfo.label).toEqual(Symbol.for('capture'));
        expect(Observe.constructorInfo.label).toEqual(Symbol.for('observe'));
        expect(Discard.constructorInfo.arity).toEqual(0);
        expect(Capture.constructorInfo.arity).toEqual(1);
        expect(Observe.constructorInfo.arity).toEqual(1);
    });
})

describe('RecordConstructorInfo', () => {
    const C1 = Record.makeBasicConstructor([1], ['x', 'y']);
    const C2 = Record.makeBasicConstructor([1], ['z', 'w']);
    it('instance comparison should ignore pointer and fieldname differences', () => {
        expect(C1(9,9)).is(C2(9,9));
        expect(C1(9,9)).not.is(C2(9,8));
    });
    it('comparison based on pointer equality should not work', () => {
        expect(C1.constructorInfo).not.toBe(C2.constructorInfo);
    });
    it('comparison based on .equals should work', () => {
        expect(C1.constructorInfo).toEqual(C2.constructorInfo);
    });
});

describe('records', () => {
    it('should have correct getConstructorInfo', () => {
        expect(Discard().getConstructorInfo()).toEqual(Discard.constructorInfo);
        expect(Capture(Discard()).getConstructorInfo()).toEqual(Capture.constructorInfo);
        expect(Observe(Capture(Discard())).getConstructorInfo()).toEqual(Observe.constructorInfo);
    });
});

describe('parsing from subarray', () => {
    it('should maintain alignment of nextbytes', () => {
        const u = Uint8Array.of(1, 1, 1, 1, 0xb1, 0x03, 0x33, 0x33, 0x33);
        const bs = Bytes.from(u.subarray(4));
        expect(decode(bs)).is("333");
    });
});

describe('common test suite', () => {
    const samples_bin = fs.readFileSync(__dirname + '/../../../tests/samples.bin');
    const samples = decodeWithAnnotations(samples_bin);

    const TestCases = Record.makeConstructor('TestCases', ['cases']);

    function DS(bs: Bytes) {
        return decode(bs);
    }
    function D(bs: Bytes) {
        return decodeWithAnnotations(bs);
    }
    function E(v: Value) {
        return encodeWithAnnotations(v);
    }

    const expectedValues = {
        annotation1: { forward: annotate(9, "abc"),
                       back: 9 },
        annotation2: { forward: annotate([[], annotate([], "x")], "abc", "def"),
                       back: [[], []] },
        annotation3: { forward: annotate(5,
                                         annotate(2, 1),
                                         annotate(4, 3)),
                       back: 5 },
        annotation5: { forward: annotate(new Record(Symbol.for('R'),
                                                    [annotate(Symbol.for('f'),
                                                              Symbol.for('af'))]),
                                         Symbol.for('ar')),
                       back: new Record(Symbol.for('R'), [Symbol.for('f')]) },
        annotation6: { forward: new Record(annotate(Symbol.for('R'),
                                                    Symbol.for('ar')),
                                           [annotate(Symbol.for('f'),
                                                     Symbol.for('af'))]),
                       back: new Record(Symbol.for('R'), [Symbol.for('f')]) },
        annotation7: { forward: annotate([], Symbol.for('a'), Symbol.for('b'), Symbol.for('c')),
                       back: [] },
        list1: { forward: [1, 2, 3, 4],
                 back: [1, 2, 3, 4] },
        record2: { value: Observe(new Record(Symbol.for("speak"), [
            Discard(),
            Capture(Discard())
        ])) },
    };

    type Variety = 'normal' | 'nondeterministic' | 'decode';

    function runTestCase(variety: Variety, tName: string, binaryForm: Bytes, annotatedTextForm: Value) {
        describe(tName, () => {
            const textForm = strip(annotatedTextForm);
            const {forward, back} = (function () {
                const entry = expectedValues[tName] || {value: textForm};
                if ('value' in entry) {
                    return {forward: entry.value, back: entry.value};
                } else if ('forward' in entry && 'back' in entry) {
                    return entry;
                } else {
                    throw new Error('Invalid expectedValues entry for ' + tName);
                }
            })();
            it('should match the expected value', () => expect(textForm).is(back));
            it('should round-trip', () => expect(DS(E(textForm))).is(back));
            it('should go forward', () => expect(DS(E(forward))).is(back));
            it('should go back', () => expect(DS(binaryForm)).is(back));
            it('should go back with annotations',
               () => expect(D(E(annotatedTextForm))).is(annotatedTextForm));
            if (variety !== 'decode' && variety !== 'nondeterministic') {
                it('should encode correctly', () => expect(E(forward)).is(binaryForm));
                it('should encode correctly with annotations',
                   () => expect(E(annotatedTextForm)).is(binaryForm));
            }
        });
    }

    const tests = peel(TestCases._.cases(peel(samples))) as Dictionary<Value>;
    tests.forEach((t0: Value, tName0: Value) => {
        const tName = Symbol.keyFor(strip(tName0) as symbol);
        const t = peel(t0) as Record;
        switch (t.label) {
            case Symbol.for('Test'):
                runTestCase('normal', tName, strip(t[0]) as Bytes, t[1]);
                break;
            case Symbol.for('NondeterministicTest'):
                runTestCase('nondeterministic', tName, strip(t[0]) as Bytes, t[1]);
                break;
            case Symbol.for('DecodeTest'):
                runTestCase('decode', tName, strip(t[0]) as Bytes, t[1]);
                break;
            case Symbol.for('DecodeError'):
                describe(tName, () => {
                    it('should fail with DecodeError', () => {
                        expect(() => D(strip(t[0]) as Bytes))
                            .toThrowFilter(e => isDecodeError(e) && !isShortPacket(e));
                    });
                });
                break;
            case Symbol.for('DecodeEOF'): // fall through
            case Symbol.for('DecodeShort'):
                describe(tName, () => {
                    it('should fail with ShortPacket', () => {
                        expect(() => D(strip(t[0]) as Bytes))
                            .toThrowFilter(e => isShortPacket(e));
                    });
                });
                break;
            case Symbol.for('ParseError'):
            case Symbol.for('ParseEOF'):
            case Symbol.for('ParseShort'):
                /* Skipped for now, until we have an implementation of text syntax */
                break;
            default:{
                const e = new Error(preserves`Unsupported test kind ${t}`);
                console.error(e);
                throw e;
            }
        }
    });
});