code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  package org.openqa.selenium.io;
  
  import static org.assertj.core.api.Assertions.assertThat;
  
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.Random;
  import org.junit.jupiter.api.Tag;
  import org.junit.jupiter.api.Test;
  
  @Tag("UnitTests")
  class FileHandlerTest {
  
    @Test
    void testFileCopy() throws IOException {
      File newFile = File.createTempFile("testFileCopy", "dst");
      File tmpFile = writeTestFile(File.createTempFile("FileUtilTest", "src"));
      assertThat(newFile.length()).isZero();
      assertThat(tmpFile.length()).isPositive();
  
      try {
        // Copy it.
        FileHandler.copy(tmpFile, newFile);
  
        assertThat(newFile.length()).isEqualTo(tmpFile.length());
      } finally {
        tmpFile.delete();
        newFile.delete();
      }
    }
  
    private File writeTestFile(File file) throws IOException {
      byte[] byteArray = new byte[16384];
      new Random().nextBytes(byteArray);
      OutputStream out = new FileOutputStream(file);
      out.write(byteArray);
      out.close();
      file.deleteOnExit();
      return file;
    }
  }
  