path: root/testing/web-platform/tests/streams/readable-byte-streams/read-min.any.js

// META: global=window,worker,shadowrealm
// META: script=../resources/rs-utils.js
// META: script=../resources/test-utils.js
'use strict';

// View buffers are detached after pull() returns, so record the information at the time that pull() was called.
function extractViewInfo(view) {
  return {
    constructor: view.constructor,
    bufferByteLength: view.buffer.byteLength,
    byteOffset: view.byteOffset,
    byteLength: view.byteLength
  };
}

promise_test(async t => {
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.unreached_func('pull() should not be called'),
  });
  const reader = rs.getReader({ mode: 'byob' });
  await promise_rejects_js(t, TypeError, reader.read(new Uint8Array(1), { min: 0 }));
}, 'ReadableStream with byte source: read({ min }) rejects if min is 0');

promise_test(async t => {
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.unreached_func('pull() should not be called'),
  });
  const reader = rs.getReader({ mode: 'byob' });
  await promise_rejects_js(t, TypeError, reader.read(new Uint8Array(1), { min: -1 }));
}, 'ReadableStream with byte source: read({ min }) rejects if min is negative');

promise_test(async t => {
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.unreached_func('pull() should not be called'),
  });
  const reader = rs.getReader({ mode: 'byob' });
  await promise_rejects_js(t, RangeError, reader.read(new Uint8Array(1), { min: 2 }));
}, 'ReadableStream with byte source: read({ min }) rejects if min is larger than view\'s length (Uint8Array)');

promise_test(async t => {
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.unreached_func('pull() should not be called'),
  });
  const reader = rs.getReader({ mode: 'byob' });
  await promise_rejects_js(t, RangeError, reader.read(new Uint16Array(1), { min: 2 }));
}, 'ReadableStream with byte source: read({ min }) rejects if min is larger than view\'s length (Uint16Array)');

promise_test(async t => {
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.unreached_func('pull() should not be called'),
  });
  const reader = rs.getReader({ mode: 'byob' });
  await promise_rejects_js(t, RangeError, reader.read(new DataView(new ArrayBuffer(1)), { min: 2 }));
}, 'ReadableStream with byte source: read({ min }) rejects if min is larger than view\'s length (DataView)');

promise_test(async t => {
  let pullCount = 0;
  const byobRequests = [];
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      const byobRequest = c.byobRequest;
      const view = byobRequest.view;
      byobRequests[pullCount] = {
        nonNull: byobRequest !== null,
        viewNonNull: view !== null,
        viewInfo: extractViewInfo(view)
      };
      if (pullCount === 0) {
        view[0] = 0x01;
        view[1] = 0x02;
        byobRequest.respond(2);
      } else if (pullCount === 1) {
        view[0] = 0x03;
        byobRequest.respond(1);
      } else if (pullCount === 2) {
        view[0] = 0x04;
        byobRequest.respond(1);
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });
  const read1 = reader.read(new Uint8Array(3), { min: 3 });
  const read2 = reader.read(new Uint8Array(1));

  const result1 = await read1;
  assert_false(result1.done, 'first result should not be done');
  assert_typed_array_equals(result1.value, new Uint8Array([0x01, 0x02, 0x03]), 'first result value');

  const result2 = await read2;
  assert_false(result2.done, 'second result should not be done');
  assert_typed_array_equals(result2.value, new Uint8Array([0x04]), 'second result value');

  assert_equals(pullCount, 3, 'pull() must have been called 3 times');

  {
    const byobRequest = byobRequests[0];
    assert_true(byobRequest.nonNull, 'first byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'first byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'first view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 3, 'first view.buffer.byteLength should be 3');
    assert_equals(viewInfo.byteOffset, 0, 'first view.byteOffset should be 0');
    assert_equals(viewInfo.byteLength, 3, 'first view.byteLength should be 3');
  }

  {
    const byobRequest = byobRequests[1];
    assert_true(byobRequest.nonNull, 'second byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'second byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'second view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 3, 'second view.buffer.byteLength should be 3');
    assert_equals(viewInfo.byteOffset, 2, 'second view.byteOffset should be 2');
    assert_equals(viewInfo.byteLength, 1, 'second view.byteLength should be 1');
  }

  {
    const byobRequest = byobRequests[2];
    assert_true(byobRequest.nonNull, 'third byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'third byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'third view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 1, 'third view.buffer.byteLength should be 1');
    assert_equals(viewInfo.byteOffset, 0, 'third view.byteOffset should be 0');
    assert_equals(viewInfo.byteLength, 1, 'third view.byteLength should be 1');
  }

}, 'ReadableStream with byte source: read({ min }), then read()');

promise_test(async t => {
  let pullCount = 0;
  const byobRequests = [];
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      const byobRequest = c.byobRequest;
      const view = byobRequest.view;
      byobRequests[pullCount] = {
        nonNull: byobRequest !== null,
        viewNonNull: view !== null,
        viewInfo: extractViewInfo(view)
      };
      if (pullCount === 0) {
        view[0] = 0x01;
        view[1] = 0x02;
        byobRequest.respond(2);
      } else if (pullCount === 1) {
        view[0] = 0x03;
        byobRequest.respond(1);
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });

  const result = await reader.read(new DataView(new ArrayBuffer(3)), { min: 3 });
  assert_false(result.done, 'result should not be done');
  assert_equals(result.value.constructor, DataView, 'result.value must be a DataView');
  assert_equals(result.value.byteOffset, 0, 'result.value.byteOffset');
  assert_equals(result.value.byteLength, 3, 'result.value.byteLength');
  assert_equals(result.value.buffer.byteLength, 3, 'result.value.buffer.byteLength');
  assert_array_equals([...new Uint8Array(result.value.buffer)], [0x01, 0x02, 0x03], `result.value.buffer contents`);

  assert_equals(pullCount, 2, 'pull() must have been called 2 times');

  {
    const byobRequest = byobRequests[0];
    assert_true(byobRequest.nonNull, 'first byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'first byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'first view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 3, 'first view.buffer.byteLength should be 3');
    assert_equals(viewInfo.byteOffset, 0, 'first view.byteOffset should be 0');
    assert_equals(viewInfo.byteLength, 3, 'first view.byteLength should be 3');
  }

  {
    const byobRequest = byobRequests[1];
    assert_true(byobRequest.nonNull, 'second byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'second byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'second view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 3, 'second view.buffer.byteLength should be 3');
    assert_equals(viewInfo.byteOffset, 2, 'second view.byteOffset should be 2');
    assert_equals(viewInfo.byteLength, 1, 'second view.byteLength should be 1');
  }

}, 'ReadableStream with byte source: read({ min }) with a DataView');

promise_test(async t => {
  let pullCount = 0;
  const byobRequests = [];
  const rs = new ReadableStream({
    type: 'bytes',
    start: t.step_func((c) => {
      c.enqueue(new Uint8Array([0x01]));
    }),
    pull: t.step_func((c) => {
      const byobRequest = c.byobRequest;
      const view = byobRequest.view;
      byobRequests[pullCount] = {
        nonNull: byobRequest !== null,
        viewNonNull: view !== null,
        viewInfo: extractViewInfo(view)
      };
      if (pullCount === 0) {
        view[0] = 0x02;
        view[1] = 0x03;
        byobRequest.respond(2);
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });

  const result = await reader.read(new Uint8Array(3), { min: 3 });
  assert_false(result.done, 'first result should not be done');
  assert_typed_array_equals(result.value, new Uint8Array([0x01, 0x02, 0x03]), 'first result value');

  assert_equals(pullCount, 1, 'pull() must have only been called once');

  const byobRequest = byobRequests[0];
  assert_true(byobRequest.nonNull, 'first byobRequest must not be null');
  assert_true(byobRequest.viewNonNull, 'first byobRequest.view must not be null');
  const viewInfo = byobRequest.viewInfo;
  assert_equals(viewInfo.constructor, Uint8Array, 'first view.constructor should be Uint8Array');
  assert_equals(viewInfo.bufferByteLength, 3, 'first view.buffer.byteLength should be 3');
  assert_equals(viewInfo.byteOffset, 1, 'first view.byteOffset should be 1');
  assert_equals(viewInfo.byteLength, 2, 'first view.byteLength should be 2');

}, 'ReadableStream with byte source: enqueue(), then read({ min })');

promise_test(async t => {
  let pullCount = 0;
  const byobRequests = [];
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      const byobRequest = c.byobRequest;
      const view = byobRequest.view;
      byobRequests[pullCount] = {
        nonNull: byobRequest !== null,
        viewNonNull: view !== null,
        viewInfo: extractViewInfo(view)
      };
      if (pullCount === 0) {
        c.enqueue(new Uint8Array([0x01, 0x02]));
      } else if (pullCount === 1) {
        c.enqueue(new Uint8Array([0x03]));
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });

  const result = await reader.read(new Uint8Array(3), { min: 3 });
  assert_false(result.done, 'first result should not be done');
  assert_typed_array_equals(result.value, new Uint8Array([0x01, 0x02, 0x03]), 'first result value');

  assert_equals(pullCount, 2, 'pull() must have been called 2 times');

  {
    const byobRequest = byobRequests[0];
    assert_true(byobRequest.nonNull, 'first byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'first byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'first view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 3, 'first view.buffer.byteLength should be 3');
    assert_equals(viewInfo.byteOffset, 0, 'first view.byteOffset should be 0');
    assert_equals(viewInfo.byteLength, 3, 'first view.byteLength should be 3');
  }

  {
    const byobRequest = byobRequests[1];
    assert_true(byobRequest.nonNull, 'second byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'second byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'second view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 3, 'second view.buffer.byteLength should be 3');
    assert_equals(viewInfo.byteOffset, 2, 'second view.byteOffset should be 2');
    assert_equals(viewInfo.byteLength, 1, 'second view.byteLength should be 1');
  }

}, 'ReadableStream with byte source: read({ min: 3 }) on a 3-byte Uint8Array, then multiple enqueue() up to 3 bytes');

promise_test(async t => {
  let pullCount = 0;
  const byobRequests = [];
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      const byobRequest = c.byobRequest;
      const view = byobRequest.view;
      byobRequests[pullCount] = {
        nonNull: byobRequest !== null,
        viewNonNull: view !== null,
        viewInfo: extractViewInfo(view)
      };
      if (pullCount === 0) {
        c.enqueue(new Uint8Array([0x01, 0x02]));
      } else if (pullCount === 1) {
        c.enqueue(new Uint8Array([0x03]));
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });

  const result = await reader.read(new Uint8Array(5), { min: 3 });
  assert_false(result.done, 'first result should not be done');
  assert_typed_array_equals(result.value, new Uint8Array([0x01, 0x02, 0x03, 0, 0]).subarray(0, 3), 'first result value');

  assert_equals(pullCount, 2, 'pull() must have been called 2 times');

  {
    const byobRequest = byobRequests[0];
    assert_true(byobRequest.nonNull, 'first byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'first byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'first view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 5, 'first view.buffer.byteLength should be 5');
    assert_equals(viewInfo.byteOffset, 0, 'first view.byteOffset should be 0');
    assert_equals(viewInfo.byteLength, 5, 'first view.byteLength should be 5');
  }

  {
    const byobRequest = byobRequests[1];
    assert_true(byobRequest.nonNull, 'second byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'second byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'second view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 5, 'second view.buffer.byteLength should be 5');
    assert_equals(viewInfo.byteOffset, 2, 'second view.byteOffset should be 2');
    assert_equals(viewInfo.byteLength, 3, 'second view.byteLength should be 3');
  }

}, 'ReadableStream with byte source: read({ min: 3 }) on a 5-byte Uint8Array, then multiple enqueue() up to 3 bytes');

promise_test(async t => {
  let pullCount = 0;
  const byobRequests = [];
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      const byobRequest = c.byobRequest;
      const view = byobRequest.view;
      byobRequests[pullCount] = {
        nonNull: byobRequest !== null,
        viewNonNull: view !== null,
        viewInfo: extractViewInfo(view)
      };
      if (pullCount === 0) {
        c.enqueue(new Uint8Array([0x01, 0x02]));
      } else if (pullCount === 1) {
        c.enqueue(new Uint8Array([0x03, 0x04]));
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });

  const result = await reader.read(new Uint8Array(5), { min: 3 });
  assert_false(result.done, 'first result should not be done');
  assert_typed_array_equals(result.value, new Uint8Array([0x01, 0x02, 0x03, 0x04, 0]).subarray(0, 4), 'first result value');

  assert_equals(pullCount, 2, 'pull() must have been called 2 times');

  {
    const byobRequest = byobRequests[0];
    assert_true(byobRequest.nonNull, 'first byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'first byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'first view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 5, 'first view.buffer.byteLength should be 5');
    assert_equals(viewInfo.byteOffset, 0, 'first view.byteOffset should be 0');
    assert_equals(viewInfo.byteLength, 5, 'first view.byteLength should be 5');
  }

  {
    const byobRequest = byobRequests[1];
    assert_true(byobRequest.nonNull, 'second byobRequest must not be null');
    assert_true(byobRequest.viewNonNull, 'second byobRequest.view must not be null');
    const viewInfo = byobRequest.viewInfo;
    assert_equals(viewInfo.constructor, Uint8Array, 'second view.constructor should be Uint8Array');
    assert_equals(viewInfo.bufferByteLength, 5, 'second view.buffer.byteLength should be 5');
    assert_equals(viewInfo.byteOffset, 2, 'second view.byteOffset should be 2');
    assert_equals(viewInfo.byteLength, 3, 'second view.byteLength should be 3');
  }

}, 'ReadableStream with byte source: read({ min: 3 }) on a 5-byte Uint8Array, then multiple enqueue() up to 4 bytes');

promise_test(async t => {
  const stream = new ReadableStream({
    start(c) {
      const view = new Uint8Array(16);
      view[0] = 0x01;
      view[8] = 0x02;
      c.enqueue(view);
    },
    pull: t.unreached_func('pull() should not be called'),
    type: 'bytes'
  });

  const byobReader = stream.getReader({ mode: 'byob' });
  const result1 = await byobReader.read(new Uint8Array(8), { min: 8 });
  assert_false(result1.done, 'result1.done');

  const view1 = result1.value;
  assert_equals(view1.constructor, Uint8Array, 'result1.value.constructor');
  assert_equals(view1.buffer.byteLength, 8, 'result1.value.buffer.byteLength');
  assert_equals(view1.byteOffset, 0, 'result1.value.byteOffset');
  assert_equals(view1.byteLength, 8, 'result1.value.byteLength');
  assert_equals(view1[0], 0x01, 'result1.value[0]');

  byobReader.releaseLock();

  const reader = stream.getReader();
  const result2 = await reader.read();
  assert_false(result2.done, 'result2.done');

  const view2 = result2.value;
  assert_equals(view2.constructor, Uint8Array, 'result2.value.constructor');
  assert_equals(view2.buffer.byteLength, 16, 'result2.value.buffer.byteLength');
  assert_equals(view2.byteOffset, 8, 'result2.value.byteOffset');
  assert_equals(view2.byteLength, 8, 'result2.value.byteLength');
  assert_equals(view2[0], 0x02, 'result2.value[0]');
}, 'ReadableStream with byte source: enqueue(), read({ min }) partially, then read()');

promise_test(async () => {
  let pullCount = 0;
  const byobRequestDefined = [];
  let byobRequestViewDefined;

  const stream = new ReadableStream({
    async pull(c) {
      byobRequestDefined.push(c.byobRequest !== null);
      const initialByobRequest = c.byobRequest;

      const transferredView = await transferArrayBufferView(c.byobRequest.view);
      transferredView[0] = 0x01;
      c.byobRequest.respondWithNewView(transferredView);

      byobRequestDefined.push(c.byobRequest !== null);
      byobRequestViewDefined = initialByobRequest.view !== null;

      ++pullCount;
    },
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });
  const result = await reader.read(new Uint8Array(1), { min: 1 });
  assert_false(result.done, 'result.done');
  assert_equals(result.value.byteLength, 1, 'result.value.byteLength');
  assert_equals(result.value[0], 0x01, 'result.value[0]');
  assert_equals(pullCount, 1, 'pull() should be called only once');
  assert_true(byobRequestDefined[0], 'byobRequest must not be null before respondWithNewView()');
  assert_false(byobRequestDefined[1], 'byobRequest must be null after respondWithNewView()');
  assert_false(byobRequestViewDefined, 'view of initial byobRequest must be null after respondWithNewView()');
}, 'ReadableStream with byte source: read({ min }), then respondWithNewView() with a transferred ArrayBuffer');

promise_test(async t => {
  const stream = new ReadableStream({
    start(c) {
      c.close();
    },
    pull: t.unreached_func('pull() should not be called'),
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });

  const result = await reader.read(new Uint8Array([0x01]), { min: 1 });
  assert_true(result.done, 'result.done');
  assert_typed_array_equals(result.value, new Uint8Array([0x01]).subarray(0, 0), 'result.value');

  await reader.closed;
}, 'ReadableStream with byte source: read({ min }) on a closed stream');

promise_test(async t => {
  let pullCount = 0;
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      if (pullCount === 0) {
        c.byobRequest.view[0] = 0x01;
        c.byobRequest.respond(1);
      } else if (pullCount === 1) {
        c.close();
        c.byobRequest.respond(0);
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });

  const result = await reader.read(new Uint8Array(3), { min: 3 });
  assert_true(result.done, 'result.done');
  assert_typed_array_equals(result.value, new Uint8Array([0x01, 0, 0]).subarray(0, 1), 'result.value');

  assert_equals(pullCount, 2, 'pull() must have been called 2 times');

  await reader.closed;
}, 'ReadableStream with byte source: read({ min }) when closed before view is filled');

promise_test(async t => {
  let pullCount = 0;
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      if (pullCount === 0) {
        c.byobRequest.view[0] = 0x01;
        c.byobRequest.view[1] = 0x02;
        c.byobRequest.respond(2);
      } else if (pullCount === 1) {
        c.byobRequest.view[0] = 0x03;
        c.byobRequest.respond(1);
        c.close();
      }
      ++pullCount;
    })
  });
  const reader = rs.getReader({ mode: 'byob' });

  const result = await reader.read(new Uint8Array(3), { min: 3 });
  assert_false(result.done, 'result.done');
  assert_typed_array_equals(result.value, new Uint8Array([0x01, 0x02, 0x03]), 'result.value');

  assert_equals(pullCount, 2, 'pull() must have been called 2 times');

  await reader.closed;
}, 'ReadableStream with byte source: read({ min }) when closed immediately after view is filled');

promise_test(async t => {
  const error1 = new Error('error1');
  const stream = new ReadableStream({
    start(c) {
      c.error(error1);
    },
    pull: t.unreached_func('pull() should not be called'),
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });
  const read = reader.read(new Uint8Array(1), { min: 1 });

  await Promise.all([
    promise_rejects_exactly(t, error1, read, 'read() must fail'),
    promise_rejects_exactly(t, error1, reader.closed, 'closed must fail')
  ]);
}, 'ReadableStream with byte source: read({ min }) on an errored stream');

promise_test(async t => {
  const error1 = new Error('error1');
  let controller;
  const stream = new ReadableStream({
    start(c) {
      controller = c;
    },
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });
  const read = reader.read(new Uint8Array(1), { min: 1 });

  controller.error(error1);

  await Promise.all([
    promise_rejects_exactly(t, error1, read, 'read() must fail'),
    promise_rejects_exactly(t, error1, reader.closed, 'closed must fail')
  ]);
}, 'ReadableStream with byte source: read({ min }), then error()');

promise_test(t => {
  let cancelCount = 0;
  let reason;

  const passedReason = new TypeError('foo');

  const stream = new ReadableStream({
    pull: t.unreached_func('pull() should not be called'),
    cancel(r) {
      if (cancelCount === 0) {
        reason = r;
      }

      ++cancelCount;

      return 'bar';
    },
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });

  const readPromise = reader.read(new Uint8Array(1), { min: 1 }).then(result => {
    assert_true(result.done, 'result.done');
    assert_equals(result.value, undefined, 'result.value');
  });

  const cancelPromise = reader.cancel(passedReason).then(result => {
    assert_equals(result, undefined, 'cancel() return value should be fulfilled with undefined');
    assert_equals(cancelCount, 1, 'cancel() should be called only once');
    assert_equals(reason, passedReason, 'reason should equal the passed reason');
  });

  return Promise.all([readPromise, cancelPromise]);
}, 'ReadableStream with byte source: getReader(), read({ min }), then cancel()');

promise_test(async t => {
  let pullCount = 0;
  let byobRequest;
  const viewInfos = [];
  const rs = new ReadableStream({
    type: 'bytes',
    pull: t.step_func((c) => {
      byobRequest = c.byobRequest;

      viewInfos.push(extractViewInfo(c.byobRequest.view));
      c.byobRequest.view[0] = 0x01;
      c.byobRequest.respond(1);
      viewInfos.push(extractViewInfo(c.byobRequest.view));

      ++pullCount;
    })
  });

  await Promise.resolve();
  assert_equals(pullCount, 0, 'pull() must not have been called yet');

  const reader = rs.getReader({ mode: 'byob' });
  const read = reader.read(new Uint8Array(3), { min: 3 });
  assert_equals(pullCount, 1, 'pull() must have been called once');
  assert_not_equals(byobRequest, null, 'byobRequest should not be null');
  assert_equals(viewInfos[0].byteLength, 3, 'byteLength before respond() should be 3');
  assert_equals(viewInfos[1].byteLength, 2, 'byteLength after respond() should be 2');

  reader.cancel().catch(t.unreached_func('cancel() should not reject'));

  const result = await read;
  assert_true(result.done, 'result.done');
  assert_equals(result.value, undefined, 'result.value');

  assert_equals(pullCount, 1, 'pull() must only be called once');

  await reader.closed;
}, 'ReadableStream with byte source: cancel() with partially filled pending read({ min }) request');

promise_test(async () => {
  let pullCalled = false;

  const stream = new ReadableStream({
    start(c) {
      const view = new Uint8Array(16);
      view[7] = 0x01;
      view[15] = 0x02;
      c.enqueue(view);
    },
    pull() {
      pullCalled = true;
    },
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });

  const result1 = await reader.read(new Uint8Array(8), { min: 8 });
  assert_false(result1.done, 'result1.done');

  const view1 = result1.value;
  assert_equals(view1.byteOffset, 0, 'result1.value.byteOffset');
  assert_equals(view1.byteLength, 8, 'result1.value.byteLength');
  assert_equals(view1[7], 0x01, 'result1.value[7]');

  const result2 = await reader.read(new Uint8Array(8), { min: 8 });
  assert_false(pullCalled, 'pull() must not have been called');
  assert_false(result2.done, 'result2.done');

  const view2 = result2.value;
  assert_equals(view2.byteOffset, 0, 'result2.value.byteOffset');
  assert_equals(view2.byteLength, 8, 'result2.value.byteLength');
  assert_equals(view2[7], 0x02, 'result2.value[7]');
}, 'ReadableStream with byte source: enqueue(), then read({ min }) with smaller views');

promise_test(async t => {
  const stream = new ReadableStream({
    start(c) {
      c.enqueue(new Uint8Array([0xaa, 0xbb, 0xcc]));
      c.close();
    },
    pull: t.unreached_func('pull() should not be called'),
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });

  await promise_rejects_js(t, TypeError, reader.read(new Uint16Array(2), { min: 2 }), 'read() must fail');
  await promise_rejects_js(t, TypeError, reader.closed, 'reader.closed should reject');
}, 'ReadableStream with byte source: 3 byte enqueue(), then close(), then read({ min }) with 2-element Uint16Array must fail');

promise_test(async t => {
  let controller;
  const stream = new ReadableStream({
    start(c) {
      controller = c;
    },
    pull: t.unreached_func('pull() should not be called'),
    type: 'bytes'
  });

  const reader = stream.getReader({ mode: 'byob' });
  const readPromise = reader.read(new Uint16Array(2), { min: 2 });

  controller.enqueue(new Uint8Array([0xaa, 0xbb, 0xcc]));
  assert_throws_js(TypeError, () => controller.close(), 'controller.close() must throw');

  await promise_rejects_js(t, TypeError, readPromise, 'read() must fail');
  await promise_rejects_js(t, TypeError, reader.closed, 'reader.closed must reject');
}, 'ReadableStream with byte source: read({ min }) with 2-element Uint16Array, then 3 byte enqueue(), then close() must fail');

promise_test(async t => {
  let pullCount = 0;
  let controller;
  const rs = new ReadableStream({
    type: 'bytes',
    start: t.step_func((c) => {
      controller = c;
    }),
    pull: t.step_func((c) => {
      ++pullCount;
    })
  });

  const [reader1, reader2] = rs.tee().map(branch => branch.getReader({ mode: 'byob' }));

  await Promise.resolve();
  assert_equals(pullCount, 0, 'pull() must not have been called yet');

  const read1 = reader1.read(new Uint8Array(3), { min: 3 });
  const read2 = reader2.read(new Uint8Array(1));

  assert_equals(pullCount, 1, 'pull() must have been called once');
  const byobRequest1 = controller.byobRequest;
  assert_equals(byobRequest1.view.byteLength, 3, 'first byobRequest.view.byteLength should be 3');
  byobRequest1.view[0] = 0x01;
  byobRequest1.respond(1);

  const result2 = await read2;
  assert_false(result2.done, 'branch2 first read() should not be done');
  assert_typed_array_equals(result2.value, new Uint8Array([0x01]), 'branch2 first read() value');

  assert_equals(pullCount, 2, 'pull() must have been called 2 times');
  const byobRequest2 = controller.byobRequest;
  assert_equals(byobRequest2.view.byteLength, 2, 'second byobRequest.view.byteLength should be 2');
  byobRequest2.view[0] = 0x02;
  byobRequest2.view[1] = 0x03;
  byobRequest2.respond(2);

  const result1 = await read1;
  assert_false(result1.done, 'branch1 read() should not be done');
  assert_typed_array_equals(result1.value, new Uint8Array([0x01, 0x02, 0x03]), 'branch1 read() value');

  const result3 = await reader2.read(new Uint8Array(2));
  assert_equals(pullCount, 2, 'pull() must only be called 2 times');
  assert_false(result3.done, 'branch2 second read() should not be done');
  assert_typed_array_equals(result3.value, new Uint8Array([0x02, 0x03]), 'branch2 second read() value');
}, 'ReadableStream with byte source: tee() with read({ min }) from branch1 and read() from branch2');