FileSystemSyncAccessHandle-truncate.https.worker.js

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This WPT test may be referenced by the following Test IDs:
- /fs/FileSystemSyncAccessHandle-truncate.https.worker.html - WPT Dashboard Interop Dashboard

importScripts("/resources/testharness.js");

importScripts('resources/sync-access-handle-test.js');

'use strict';

sync_access_handle_test((t, handle) => {

  // Without this assertion, the test passes even if truncate is not defined.

  assert_implements(handle.truncate,

    "SyncAccessHandle.truncate is not implemented.");

  handle.truncate(4);

  assert_equals(handle.getSize(), 4);

  handle.truncate(2);

  assert_equals(handle.getSize(), 2);

  handle.truncate(7);

  assert_equals(handle.getSize(), 7);

  handle.truncate(0);

  assert_equals(handle.getSize(), 0);

  assert_throws_js(TypeError, () => handle.truncate(-4));

}, 'test SyncAccessHandle.truncate with different sizes');

sync_access_handle_test((t, handle) => {

  const writeBuffer = new Uint8Array(4);

  writeBuffer.set([96, 97, 98, 99]);

  handle.write(writeBuffer, {at: 0});

  handle.truncate(2);

  let readBuffer = new Uint8Array(6);

  assert_equals(2, handle.read(readBuffer, {at: 0}));

  let expected = new Uint8Array(6);

  expected.set([96, 97, 0, 0, 0, 0]);

  assert_array_equals(expected, readBuffer);

  // Resize the file to 6, expect that everything beyond the old size is '0'.

  handle.truncate(6);

  assert_equals(6, handle.read(readBuffer, {at: 0}));

  assert_array_equals(expected, readBuffer);

}, 'test SyncAccessHandle.truncate after SyncAccessHandle.write');

sync_access_handle_test((t, handle) => {

  const writeBuffer = new Uint8Array(4);

  writeBuffer.set([96, 97, 98, 99]);

  handle.write(writeBuffer, {at: 0});

  // Moves cursor to 2

  handle.truncate(2);

  let readBuffer = new Uint8Array(256);

  assert_equals(handle.read(readBuffer), 0);

  writeBuffer.set([100, 101, 102, 103]);

  handle.write(writeBuffer);

  assert_equals(handle.read(readBuffer, {at: 0}), 6);

  let expected = new Uint8Array(256);

  expected.set([96, 97, 100, 101, 102, 103]);

  assert_array_equals(readBuffer, expected);

  // Resize the file to 10, expect that everything beyond the old size is '0'.

  handle.truncate(10); // file cursor should still be at 6

  // overwrite two bytes

  const writeBuffer2 = new Uint8Array(2);

  writeBuffer2.set([110, 111]);

  handle.write(writeBuffer2);

  expected = new Uint8Array(256);

  expected.set([96, 97, 100, 101, 102, 103, 110, 111, 0, 0]);

  assert_equals(handle.read(readBuffer, {at: 0}), 10);

  assert_array_equals(readBuffer, expected);

}, 'Test truncate effect on cursor');

done();