packages/inference/src/vendor/fetch-event-source/parse.spec.ts

import { expect, it, describe } from "vitest";
const fail = (msg: string) => { throw new Error(msg) };

/**
 This file is a part of fetch-event-source package (as of v2.0.1)
 https://github.com/Azure/fetch-event-source/blob/v2.0.1/src/parse.spec.ts

 Full package can be used after it is made compatible with nodejs:
 https://github.com/Azure/fetch-event-source/issues/20

 Below is the fetch-event-source package license:

 MIT License

 Copyright (c) Microsoft Corporation.

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE

 */

import * as parse from './parse';

describe('parse', () => {
    const encoder = new TextEncoder();
    const decoder = new TextDecoder();

    describe('getLines', () => {
        it('single line', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual('id: abc');
                expect(fieldLength).toEqual(2);
            });

            // act:
            next(encoder.encode('id: abc\n'));
            
            // assert:
            expect(lineNum).toBe(1);
        });

        it('multiple lines', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual(lineNum === 1 ? 'id: abc' : 'data: def');
                expect(fieldLength).toEqual(lineNum === 1 ? 2 : 4);
            });
            
            // act:
            next(encoder.encode('id: abc\n'));
            next(encoder.encode('data: def\n'));
            
            // assert:
            expect(lineNum).toBe(2);
        });

        it('single line split across multiple arrays', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual('id: abc');
                expect(fieldLength).toEqual(2);
            });

            // act:
            next(encoder.encode('id: a'));
            next(encoder.encode('bc\n'));
            
            // assert:
            expect(lineNum).toBe(1);
        });

        it('multiple lines split across multiple arrays', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual(lineNum === 1 ? 'id: abc' : 'data: def');
                expect(fieldLength).toEqual(lineNum === 1 ? 2 : 4);
            });
            
            // act:
            next(encoder.encode('id: ab'));
            next(encoder.encode('c\nda'));
            next(encoder.encode('ta: def\n'));
            
            // assert:
            expect(lineNum).toBe(2);
        });

        it('new line', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual('');
                expect(fieldLength).toEqual(-1);
            });

            // act:
            next(encoder.encode('\n'));
            
            // assert:
            expect(lineNum).toBe(1);
        });

        it('comment line', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual(': this is a comment');
                expect(fieldLength).toEqual(0);
            });

            // act:
            next(encoder.encode(': this is a comment\n'));
            
            // assert:
            expect(lineNum).toBe(1);
        });

        it('line with no field', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual('this is an invalid line');
                expect(fieldLength).toEqual(-1);
            });

            // act:
            next(encoder.encode('this is an invalid line\n'));
            
            // assert:
            expect(lineNum).toBe(1);
        });

        it('line with multiple colons', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual('id: abc: def');
                expect(fieldLength).toEqual(2);
            });

            // act:
            next(encoder.encode('id: abc: def\n'));
            
            // assert:
            expect(lineNum).toBe(1);
        });

        it('single byte array with multiple lines separated by \\n', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual(lineNum === 1 ? 'id: abc' : 'data: def');
                expect(fieldLength).toEqual(lineNum === 1 ? 2 : 4);
            });

            // act:
            next(encoder.encode('id: abc\ndata: def\n'));
            
            // assert:
            expect(lineNum).toBe(2);
        });

        it('single byte array with multiple lines separated by \\r', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual(lineNum === 1 ? 'id: abc' : 'data: def');
                expect(fieldLength).toEqual(lineNum === 1 ? 2 : 4);
            });

            // act:
            next(encoder.encode('id: abc\rdata: def\r'));
            
            // assert:
            expect(lineNum).toBe(2);
        });

        it('single byte array with multiple lines separated by \\r\\n', () => {
            // arrange:
            let lineNum = 0;
            const next = parse.getLines((line, fieldLength) => {
                ++lineNum;
                expect(decoder.decode(line)).toEqual(lineNum === 1 ? 'id: abc' : 'data: def');
                expect(fieldLength).toEqual(lineNum === 1 ? 2 : 4);
            });

            // act:
            next(encoder.encode('id: abc\r\ndata: def\r\n'));
            
            // assert:
            expect(lineNum).toBe(2);
        });
    });

    describe('getMessages', () => {
        it('happy path', () => {
            // arrange:
            let msgNum = 0;
            const next = parse.getMessages(id => {
                expect(id).toEqual('abc');
            }, retry => {
                expect(retry).toEqual(42);
            }, msg => {
                ++msgNum;
                expect(msg).toEqual({
                    retry: 42,
                    id: 'abc',
                    event: 'def',
                    data: 'ghi'
                });
            });

            // act:
            next(encoder.encode('retry: 42'), 5);
            next(encoder.encode('id: abc'), 2);
            next(encoder.encode('event:def'), 5);
            next(encoder.encode('data:ghi'), 4);
            next(encoder.encode(''), -1);

            // assert:
            expect(msgNum).toBe(1);
        });

        it('skip unknown fields', () => {
            let msgNum = 0;
            const next = parse.getMessages(id => {
                expect(id).toEqual('abc');
            }, _retry => {
                fail('retry should not be called');
            }, msg => {
                ++msgNum;
                expect(msg).toEqual({
                    id: 'abc',
                    data: '',
                    event: '',
                    retry: undefined,
                });
            });

            // act:
            next(encoder.encode('id: abc'), 2);
            next(encoder.encode('foo: null'), 3);
            next(encoder.encode(''), -1);

            // assert:
            expect(msgNum).toBe(1);
        });
        
        it('ignore non-integer retry', () => {
            let msgNum = 0;
            const next = parse.getMessages(_id => {
                fail('id should not be called');
            }, _retry => {
                fail('retry should not be called');
            }, msg => {
                ++msgNum;
                expect(msg).toEqual({
                    id: '',
                    data: '',
                    event: '',
                    retry: undefined,
                });
            });

            // act:
            next(encoder.encode('retry: def'), 5);
            next(encoder.encode(''), -1);

            // assert:
            expect(msgNum).toBe(1);
        });

        it('skip comment-only messages', () => {
            // arrange:
            let msgNum = 0;
            const next = parse.getMessages(id => {
                expect(id).toEqual('123');
            }, _retry => {
                fail('retry should not be called');
            }, msg => {
                ++msgNum;
                expect(msg).toEqual({
                    retry: undefined,
                    id: '123',
                    event: 'foo ',
                    data: '',
                });
            });

            // act:
            next(encoder.encode('id:123'), 2);
            next(encoder.encode(':'), 0);
            next(encoder.encode(':    '), 0);
            next(encoder.encode('event: foo '), 5);
            next(encoder.encode(''), -1);

            // assert:
            expect(msgNum).toBe(1);
        });

        it('should append data split across multiple lines', () => {
            // arrange:
            let msgNum = 0;
            const next = parse.getMessages(_id => {
                fail('id should not be called');
            }, _retry => {
                fail('retry should not be called');
            }, msg => {
                ++msgNum;
                expect(msg).toEqual({
                    data: 'YHOO\n+2\n\n10',
                    id: '',
                    event: '',
                    retry: undefined,
                });
            });

            // act:
            next(encoder.encode('data:YHOO'), 4);
            next(encoder.encode('data: +2'), 4);
            next(encoder.encode('data'), 4);
            next(encoder.encode('data: 10'), 4);
            next(encoder.encode(''), -1);

            // assert:
            expect(msgNum).toBe(1);
        });

        it('should reset id if sent multiple times', () => {
            // arrange:
            const expectedIds = ['foo', ''];
            let idsIdx = 0;
            let msgNum = 0;
            const next = parse.getMessages(id => {
                expect(id).toEqual(expectedIds[idsIdx]);
                ++idsIdx;
            }, _retry => {
                fail('retry should not be called');
            }, msg => {
                ++msgNum;
                expect(msg).toEqual({
                    data: '',
                    id: '',
                    event: '',
                    retry: undefined,
                });
            });

            // act:
            next(encoder.encode('id: foo'), 2);
            next(encoder.encode('id'), 2);
            next(encoder.encode(''), -1);

            // assert:
            expect(idsIdx).toBe(2);
            expect(msgNum).toBe(1);
        });
    });
});