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// Copyright (c) 2025 Cloudflare, Inc.
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// Licensed under the Apache 2.0 license found in the LICENSE file or at:
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//     https://opensource.org/licenses/Apache-2.0
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import { writeSync, ReadStream } from 'node:fs';
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import { Buffer } from 'node:buffer';
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import { Readable } from 'node:stream';
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import assert from 'node:assert';
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export const processStdioPropertiesTest = {
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  test() {
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    assert.strictEqual(process.stdin.fd, 0, 'stdin should have fd 0');
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    assert(
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      process.stdin instanceof Readable,
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      'stdin should be instance of Readable'
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    );
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    assert(
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      process.stdin instanceof ReadStream,
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      'stdin should be instance of ReadStream'
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    );
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  },
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};
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export const fdBasedOperationsTest = {
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  test() {
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    const message = 'Direct writeSync to stdout\n';
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    const buffer = Buffer.from(message);
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    const bytesWritten = writeSync(1, buffer);
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    assert.strictEqual(
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      bytesWritten,
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      buffer.length,
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      'writeSync should return correct byte count'
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    );
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    const errorMessage = 'Direct writeSync to stderr\n';
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    const errorBuffer = Buffer.from(errorMessage);
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    const errorBytesWritten = writeSync(2, errorBuffer);
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    assert.strictEqual(
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      errorBytesWritten,
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      errorBuffer.length,
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      'writeSync to stderr should return correct byte count'
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    );
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  },
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};
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export const largeWriteTruncationTest = {
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  test() {
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    const largeBuffer = Buffer.alloc(4001 * 5, 'A'.repeat(4000) + '\n');
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    largeBuffer[0] = 66;
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    largeBuffer[4001 * 5 - 1] = 67;
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    const bytesWritten = writeSync(1, largeBuffer);
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    assert.strictEqual(
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      bytesWritten,
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      16 * 1024,
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      'Direct fd write should be truncated to 16KiB'
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    );
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  },
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};