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446import { describe, it, expect } from 'vitest';
import { ReadableStreamBlockReader, readUntilBoundary } from '../reader';
import {
utf8Encode,
iterableToStream,
streamChunks,
streamText,
} from './utils';
// NOTE(@kitten): This is pretty dense set of tests, but they simply are designed
// to reach 100% test coverage (pnpm test --coverage)
describe(ReadableStreamBlockReader, () => {
it('allows block-wise reads from a byte stream emitting right-sized chunks', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 3, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5, 6, 7]));
await expect(reader.read()).resolves.toEqual(
new Uint8Array([8, 9, 10, 11])
);
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows block-wise reads from a byte stream emitting undersized chunks (even)', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 4, chunkSize: 3 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5, 6, 7]));
await expect(reader.read()).resolves.toEqual(
new Uint8Array([8, 9, 10, 11])
);
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows block-wise reads from a byte stream emitting undersized chunks (uneven)', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 5, chunkSize: 3 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5, 6, 7]));
await expect(reader.read()).resolves.toEqual(
new Uint8Array([8, 9, 10, 11])
);
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(new Uint8Array([12, 13, 14]));
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows block-wise reads from a byte stream emitting oversized chunks (even)', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 3, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 3);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([3, 4, 5]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([6, 7, 8]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([9, 10, 11]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows block-wise reads from a byte stream emitting oversized chunks (uneven)', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 2, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 3);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([3, 4, 5]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(new Uint8Array([6, 7]));
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows block-wise reads from a byte stream emitting multiply-oversized chunks (even)', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 2, chunkSize: 5 })
);
const reader = new ReadableStreamBlockReader(stream, 2);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([2, 3]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([6, 7]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([8, 9]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows partial final blocks to be returned when `true` is passed to read()', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 2, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 3);
await expect(reader.read(true)).resolves.toEqual(new Uint8Array([0, 1, 2]));
await expect(reader.read(true)).resolves.toEqual(new Uint8Array([3, 4, 5]));
await expect(reader.read(true)).resolves.toEqual(new Uint8Array([6, 7]));
await expect(reader.read(true)).resolves.toEqual(null);
});
it('allows block-wise reads from a byte stream emitting multiply-oversized chunks (uneven)', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 1, chunkSize: 5 })
);
const reader = new ReadableStreamBlockReader(stream, 2);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([2, 3]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(new Uint8Array([4]));
});
it('allows block-wise reads from a byte stream emitting multiply-oversized chunks (single)', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 1, chunkSize: 10 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5, 6, 7]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(new Uint8Array([8, 9]));
});
it('allows skipping bytes for undersized chunks at end of blocks', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 4, chunkSize: 2 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.skip(2)).resolves.toBe(0);
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(new Uint8Array([6, 7]));
});
it('allows skipping bytes for undersized chunks at beginning of blocks', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 4, chunkSize: 2 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.skip(2)).resolves.toBe(0);
await expect(reader.read()).resolves.toEqual(new Uint8Array([2, 3, 4, 5]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(new Uint8Array([6, 7]));
});
it('allows skipping bytes for oversized chunks at end of blocks', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 1, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 2);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1]));
await expect(reader.skip(2)).resolves.toBe(0);
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows skipping bytes for oversized chunks at beginning of blocks', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 1, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 2);
await expect(reader.skip(2)).resolves.toBe(0);
await expect(reader.read()).resolves.toEqual(new Uint8Array([2, 3]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows skipping bytes for multiply-oversized chunks', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 1, chunkSize: 6 })
);
const reader = new ReadableStreamBlockReader(stream, 2);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1]));
await expect(reader.skip(2)).resolves.toBe(0);
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows skipping uneven number of bytes', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 3, chunkSize: 2 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.read()).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.skip(2)).resolves.toBe(0);
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows skipping excessive number of bytes', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 3, chunkSize: 2 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
await expect(reader.skip(8)).resolves.toBe(2);
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('allows pulling chunks as-is with matching input size', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 2, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 2);
await expect(reader.pull(8)).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.pull(8)).resolves.toEqual(new Uint8Array([4, 5, 6, 7]));
await expect(reader.pull(8)).resolves.toEqual(null);
});
it('allows pulling chunks as-is with matching output size', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 2, chunkSize: 4 })
);
const reader = new ReadableStreamBlockReader(stream, 2);
await expect(reader.pull(8)).resolves.toEqual(new Uint8Array([0, 1, 2, 3]));
await expect(reader.pull()).resolves.toEqual(new Uint8Array([4, 5]));
await expect(reader.pull()).resolves.toEqual(new Uint8Array([6, 7]));
await expect(reader.pull()).resolves.toEqual(null);
});
it('respects pushed back buffers', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 1, chunkSize: 8 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
let chunk: Uint8Array | null;
expect((chunk = await reader.read())).toEqual(new Uint8Array([0, 1, 2, 3]));
reader.pushback(chunk!);
await expect(reader.read()).resolves.toEqual(chunk);
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5, 6, 7]));
await expect(reader.read()).resolves.toEqual(null);
await expect(reader.pull()).resolves.toEqual(null);
});
it('combines pushed back buffers with other buffers', async () => {
const stream = iterableToStream(
streamChunks({ numChunks: 1, chunkSize: 8 })
);
const reader = new ReadableStreamBlockReader(stream, 4);
let chunk: Uint8Array | null;
expect((chunk = await reader.read())).toEqual(new Uint8Array([0, 1, 2, 3]));
reader.pushback(new Uint8Array([1, 2, 3]));
reader.pushback(new Uint8Array([0]));
await expect(reader.read()).resolves.toEqual(chunk);
await expect(reader.read()).resolves.toEqual(new Uint8Array([4, 5, 6, 7]));
await expect(reader.pull()).resolves.toEqual(null);
});
});
describe(readUntilBoundary, () => {
const BOUNDARY = '--boundary\r\n';
it('throws if chunk size is smaller than boundary', async () => {
await expect(async () => {
const stream = iterableToStream(streamText('', 1));
const reader = new ReadableStreamBlockReader(stream, 4);
for await (const _chunk of readUntilBoundary(
reader,
utf8Encode(BOUNDARY)
)) {
// noop
}
}).rejects.toThrow(/Boundary must be shorter/);
});
it('returns bytes until boundary, even between two chunks', async () => {
const stream = iterableToStream(
streamText(`once upon a time...${BOUNDARY}...the end of the story`, 4)
);
const reader = new ReadableStreamBlockReader(stream, 12);
// Reads data until a boundary across two chunks
let output = '';
const decoder = new TextDecoder();
for await (const chunk of readUntilBoundary(reader, utf8Encode(BOUNDARY))) {
expect(chunk).not.toBe(null);
output += decoder.decode(chunk!);
}
expect(output).toBe('once upon a time...');
// Continues exposing data after the boundary:
let after = '';
let chunk: Uint8Array | null;
while ((chunk = await reader.pull())) after += decoder.decode(chunk);
expect(after).toBe('...the end of the story');
});
it('handles boundary-like strings', async () => {
const stream = iterableToStream(
streamText(
`once upon a time...${BOUNDARY.slice(0, -2)}${BOUNDARY}...the end of the story`,
4
)
);
const reader = new ReadableStreamBlockReader(stream, 12);
// Reads data until a boundary across two chunks
let output = '';
const decoder = new TextDecoder();
for await (const chunk of readUntilBoundary(reader, utf8Encode(BOUNDARY))) {
expect(chunk).not.toBe(null);
output += decoder.decode(chunk!);
}
expect(output).toBe(`once upon a time...${BOUNDARY.slice(0, -2)}`);
// Continues exposing data after the boundary:
let after = '';
let chunk: Uint8Array | null;
while ((chunk = await reader.pull())) after += decoder.decode(chunk);
expect(after).toBe('...the end of the story');
});
it('returns immediately when boundary is first item', async () => {
const stream = iterableToStream(
streamText(BOUNDARY + 'test', BOUNDARY.length)
);
const reader = new ReadableStreamBlockReader(stream, BOUNDARY.length);
let chunks = 0;
for await (const chunk of readUntilBoundary(reader, utf8Encode(BOUNDARY))) {
expect(chunk).toEqual(new Uint8Array([]));
chunks++;
}
expect(chunks).toBe(1);
expect(await reader.pull()).toEqual(new Uint8Array(utf8Encode('test')));
});
it('aborts with null yield for EOF', async () => {
const stream = iterableToStream(streamText('some longer string', 4));
const reader = new ReadableStreamBlockReader(stream, 12);
const chunks: (Uint8Array | null)[] = [];
for await (const chunk of readUntilBoundary(reader, utf8Encode(BOUNDARY))) {
if (chunk) {
const copy = new Uint8Array(chunk.byteLength);
copy.set(chunk);
chunks.push(copy);
} else {
chunks.push(chunk);
}
}
expect(chunks).toMatchInlineSnapshot(`
[
Uint8Array [
115,
111,
109,
101,
32,
108,
111,
110,
103,
101,
114,
32,
],
Uint8Array [
115,
116,
114,
105,
110,
103,
],
null,
]
`);
});
it('aborts with null yield for EOF while looking at partial boundary', async () => {
const stream = iterableToStream(
streamText(`some longer string${BOUNDARY.slice(0, 4)}`, 4)
);
const reader = new ReadableStreamBlockReader(stream, 12);
const chunks: (Uint8Array | null)[] = [];
for await (const chunk of readUntilBoundary(reader, utf8Encode(BOUNDARY))) {
if (chunk) {
const copy = new Uint8Array(chunk.byteLength);
copy.set(chunk);
chunks.push(copy);
} else {
chunks.push(chunk);
}
}
expect(chunks).toMatchInlineSnapshot(`
[
Uint8Array [
115,
111,
109,
101,
32,
108,
111,
110,
103,
101,
114,
32,
],
null,
]
`);
});
it('handles randomized boundaries', async () => {
function rand(length: number): string {
let result = '';
const characters =
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
const charactersLength = characters.length;
for (let i = 0; i < length; i++)
result += characters.charAt(
Math.floor(Math.random() * charactersLength)
);
return result;
}
for (let ITERATION = 0; ITERATION < 500; ITERATION++) {
const before = rand(Math.round(Math.random() * 100));
const after = rand(Math.round(Math.random() * 100));
const stream = iterableToStream(
streamText(`${before}${BOUNDARY}${after}`, 4)
);
const reader = new ReadableStreamBlockReader(stream, 12);
// Reads data until a boundary across two chunks
let actual = '';
const decoder = new TextDecoder();
for await (const chunk of readUntilBoundary(reader, utf8Encode(BOUNDARY)))
actual += decoder.decode(chunk!);
expect(actual).toBe(before);
// Continues exposing data after the boundary:
actual = '';
let chunk: Uint8Array | null;
while ((chunk = await reader.pull())) actual += decoder.decode(chunk);
expect(actual).toBe(after);
}
});
});