"use strict";

Components.utils.import("resource://gre/modules/osfile.jsm");
Components.utils.import("resource://gre/modules/commonjs/sdk/core/promise.js");
Components.utils.import("resource://gre/modules/Task.jsm");

// The following are used to compare against a well-tested reference
// implementation of file I/O.
Components.utils.import("resource://gre/modules/NetUtil.jsm");
Components.utils.import("resource://gre/modules/FileUtils.jsm");
Components.utils.import("resource://gre/modules/Services.jsm");

let myok = ok;
let myis = is;
let myinfo = info;
let myisnot = isnot;

let isPromise = function ispromise(value) {
  return value != null && typeof value == "object" && "then" in value;
};

let maketest = function(prefix, test) {
  let utils = {
    ok: function ok(t, m) {
      myok(t, prefix + ": " + m);
    },
    is: function is(l, r, m) {
      myis(l, r, prefix + ": " + m);
    },
    isnot: function isnot(l, r, m) {
      myisnot(l, r, prefix + ": " + m);
    },
    info: function info(m) {
      myinfo(prefix + ": " + m);
    },
    fail: function fail(m) {
      utils.ok(false, m);
    },
    okpromise: function okpromise(t, m) {
      return t.then(
        function onSuccess() {
          util.ok(true, m);
        },
        function onFailure() {
          util.ok(false, m);
        }
      );
    }
  };
  return function runtest() {
    utils.info("Entering");
    try {
      let result = test.call(this, utils);
      if (!isPromise(result)) {
        throw new TypeError("The test did not return a promise");
      }
      utils.info("This was a promise");
      // The test returns a promise
      result = result.then(function test_complete() {
        utils.info("Complete");
      }, function catch_uncaught_errors(err) {
        utils.fail("Uncaught error " + err);
        if (err && typeof err == "object" && "stack" in err) {
          utils.fail("at " + err.stack);
        }
      });
      return result;
    } catch (x) {
      utils.fail("Error " + x + " at " + x.stack);
      return null;
    }
  };
};

/**
 * Fetch asynchronously the contents of a file using xpcom.
 *
 * Used for comparing xpcom-based results to os.file-based results.
 *
 * @param {string} path The _absolute_ path to the file.
 * @return {promise}
 * @resolves {string} The contents of the file.
 */
let reference_fetch_file = function reference_fetch_file(path, test) {
  test.info("Fetching file " + path);
  let promise = Promise.defer();
  let file = new FileUtils.File(path);
  NetUtil.asyncFetch(file,
    function(stream, status) {
      if (!Components.isSuccessCode(status)) {
        promise.reject(status);
        return;
      }
      let result, reject;
      try {
        result = NetUtil.readInputStreamToString(stream, stream.available());
      } catch (x) {
        reject = x;
      }
      stream.close();
      if (reject) {
        promise.reject(reject);
      } else {
        promise.resolve(result);
      }
  });
  return promise.promise;
};

/**
 * Compare asynchronously the contents two files using xpcom.
 *
 * Used for comparing xpcom-based results to os.file-based results.
 *
 * @param {string} a The _absolute_ path to the first file.
 * @param {string} b The _absolute_ path to the second file.
 *
 * @resolves {null}
 */
let reference_compare_files = function reference_compare_files(a, b, test) {
  test.info("Comparing files " + a + " and " + b);
  let a_contents = yield reference_fetch_file(a, test);
  let b_contents = yield reference_fetch_file(b, test);
  is(a_contents, b_contents, "Contents of files " + a + " and " + b + " match");
};

let reference_dir_contents = function reference_dir_contents(path) {
  let result = [];
  let entries = new FileUtils.File(path).directoryEntries;
  while (entries.hasMoreElements()) {
    let entry = entries.getNext().QueryInterface(Components.interfaces.nsILocalFile);
    result.push(entry.path);
  }
  return result;
};

let test = maketest("Main", function main(test) {
  return Task.spawn(function() {
    SimpleTest.waitForExplicitFinish();
    yield test_constants();
    yield test_path();
    yield test_open();
    yield test_stat();
    yield test_debug();
    yield test_info_features_detect();
    yield test_read_write();
    yield test_read_write_all();
    yield test_position();
    yield test_copy();
    yield test_mkdir();
    yield test_iter();
    yield test_exists();
    yield test_debug_test();
    yield test_system_shutdown();
    yield test_duration();
    info("Test is over");
    SimpleTest.finish();
  });
});

/**
 * A file that we know exists and that can be used for reading.
 */
let EXISTING_FILE = OS.Path.join("chrome", "toolkit", "components",
  "osfile", "tests", "mochi", "main_test_osfile_async.js");

/**
 * Test that OS.Constants is defined correctly.
 */
let test_constants = maketest("constants", function constants(test) {
  return Task.spawn(function() {
    test.isnot(OS.Constants, null, "OS.Constants exists");
    test.ok(OS.Constants.Win || OS.Constants.libc, "OS.Constants.Win exists or OS.Constants.Unix exists");
    test.isnot(OS.Constants.Path, null, "OS.Constants.Path exists");
    test.isnot(OS.Constants.Sys, null, "OS.Constants.Sys exists");
  });
});

/**
 * Test that OS.Constants.Path paths are consistent.
 */
let test_path = maketest("path",  function path(test) {
  return Task.spawn(function() {
    test.ok(OS.Path, "OS.Path exists");
    test.ok(OS.Constants.Path, "OS.Constants.Path exists");
    test.is(OS.Constants.Path.tmpDir, Services.dirsvc.get("TmpD", Components.interfaces.nsIFile).path, "OS.Constants.Path.tmpDir is correct");
    test.is(OS.Constants.Path.profileDir, Services.dirsvc.get("ProfD", Components.interfaces.nsIFile).path, "OS.Constants.Path.profileDir is correct");
    test.is(OS.Constants.Path.localProfileDir, Services.dirsvc.get("ProfLD", Components.interfaces.nsIFile).path, "OS.Constants.Path.localProfileDir is correct");
  });
});

/**
 * Test OS.File.open for reading:
 * - with an existing file (should succeed);
 * - with a non-existing file (should fail);
 * - with inconsistent arguments (should fail).
 */
let test_open = maketest("open",  function open(test) {
  return Task.spawn(function() {
    // Attempt to open a file that does not exist, ensure that it yields the
    // appropriate error.
    try {
      let fd = yield OS.File.open(OS.Path.join(".", "This file does not exist"));
      test.ok(false, "File opening 1 succeeded (it should fail)" + fd);
    } catch (err) {
      test.ok(true, "File opening 1 failed " + err);
      test.ok(err instanceof OS.File.Error, "File opening 1 returned a file error");
      test.ok(err.becauseNoSuchFile, "File opening 1 informed that the file does not exist");
    }

    // Attempt to open a file with the wrong args, so that it fails before
    // serialization, ensure that it yields the appropriate error.
    test.info("Attempting to open a file with wrong arguments");
    try {
      let fd = yield OS.File.open(1, 2, 3);
      test.ok(false, "File opening 2 succeeded (it should fail)" + fd);
    } catch (err) {
      test.ok(true, "File opening 2 failed " + err);
      test.ok(!(err instanceof OS.File.Error), "File opening 2 returned something that is not a file error");
      test.ok(err.constructor.name == "TypeError", "File opening 2 returned a TypeError");
    }

    // Attempt to open a file correctly
    test.info("Attempting to open a file correctly");
    let openedFile = yield OS.File.open(EXISTING_FILE);
    test.ok(true, "File opened correctly");

    test.info("Attempting to close a file correctly");
    yield openedFile.close();

    test.info("Attempting to close a file again");
    yield openedFile.close();
  });
});

/**
 * Test OS.File.stat and OS.File.prototype.stat
 */
let test_stat = maketest("stat", function stat(test) {
  return Task.spawn(function() {
    // Open a file and stat it
    let file = yield OS.File.open(EXISTING_FILE);
    let stat1;

    try {
      test.info("Stating file");
      stat1 = yield file.stat();
      test.ok(true, "stat has worked " + stat1);
      test.ok(stat1, "stat is not empty");
    } finally {
      yield file.close();
    }

    // Stat the same file without opening it
    test.info("Stating a file without opening it");
    let stat2 = yield OS.File.stat(EXISTING_FILE);
    test.ok(true, "stat 2 has worked " + stat2);
    test.ok(stat2, "stat 2 is not empty");
    for (let key in stat2) {
      test.is("" + stat1[key], "" + stat2[key], "Stat field " + key + "is the same");
    }
  });
});

/**
 * Test feature detection using OS.File.Info.prototype on main thread
 */
let test_info_features_detect = maketest("features_detect", function features_detect(test) {
  return Task.spawn(function() {
    if (OS.Constants.Win) {
      // see if winBirthDate is defined
      if ("winBirthDate" in OS.File.Info.prototype) {
        test.ok(true, "winBirthDate is defined");
      } else {
        test.fail("winBirthDate not defined though we are under Windows");
      }
    } else if (OS.Constants.libc) {
      // see if unixGroup is defined
      if ("unixGroup" in OS.File.Info.prototype) {
        test.ok(true, "unixGroup is defined");
      } else {
        test.fail("unixGroup is not defined though we are under Unix");
      }
    }
  });
});

/**
 * Test OS.File.prototype.{read, readTo, write}
 */
let test_read_write = maketest("read_write", function read_write(test) {
  return Task.spawn(function() {
    // Test readTo/write
    let currentDir = yield OS.File.getCurrentDirectory();
    let pathSource = OS.Path.join(currentDir, EXISTING_FILE);
    let pathDest = OS.Path.join(OS.Constants.Path.tmpDir,
      "osfile async test.tmp");

    let fileSource = yield OS.File.open(pathSource);
    test.info("Input file opened");
    let fileDest = yield OS.File.open(pathDest,
      { truncate: true, read: true, write: true});
    test.info("Output file opened");

    let stat = yield fileSource.stat();
    test.info("Input stat worked");
    let size = stat.size;
    let array = new Uint8Array(size);

    try {
      test.info("Now calling readTo");
      let readLength = yield fileSource.readTo(array);
      test.info("ReadTo worked");
      test.is(readLength, size, "ReadTo got all bytes");
      let writeLength = yield fileDest.write(array);
      test.info("Write worked");
      test.is(writeLength, size, "Write wrote all bytes");

      // Test read
      yield fileSource.setPosition(0);
      let readAllResult = yield fileSource.read();
      test.info("ReadAll worked");
      test.is(readAllResult.length, size, "ReadAll read all bytes");
      test.is(Array.prototype.join.call(readAllResult),
              Array.prototype.join.call(array),
              "ReadAll result is correct");
    } finally {
      // Close stuff
      yield fileSource.close();
      yield fileDest.close();
      test.info("Files are closed");
    }

    stat = yield OS.File.stat(pathDest);
    test.is(stat.size, size, "Both files have the same size");
    yield reference_compare_files(pathSource, pathDest, test);

    // Cleanup.
    OS.File.remove(pathDest);
  });
});

/**
 * Test OS.File.prototype.{writeAtomic}
 */
let test_read_write_all = maketest("read_write_all", function read_write_all(test) {
  return Task.spawn(function() {
    let pathDest = OS.Path.join(OS.Constants.Path.tmpDir,
      "osfile async test read writeAtomic.tmp");
    let tmpPath = pathDest + ".tmp";

    // Check that read + writeAtomic performs a correct copy
    let currentDir = yield OS.File.getCurrentDirectory();
    let pathSource = OS.Path.join(currentDir, EXISTING_FILE);
    let contents = yield OS.File.read(pathSource);
    test.ok(contents, "Obtained contents");
    let options = {tmpPath: tmpPath};
    let optionsBackup = {tmpPath: tmpPath};
    let bytesWritten = yield OS.File.writeAtomic(pathDest, contents, options);
    test.is(contents.byteLength, bytesWritten, "Wrote the correct number of bytes");

    // Check that options are not altered
    test.is(Object.keys(options).length, Object.keys(optionsBackup).length,
            "The number of options was not changed");
    for (let k in options) {
      test.is(options[k], optionsBackup[k], "Option was not changed");
    }
    yield reference_compare_files(pathSource, pathDest, test);

    // Check that temporary file was removed
    test.info("Compare complete");
    test.ok(!(new FileUtils.File(tmpPath).exists()), "Temporary file was removed");

    // Check that writeAtomic fails if noOverwrite is true and the destination
    // file already exists!
    let view = new Uint8Array(contents.buffer, 10, 200);
    try {
      options = {tmpPath: tmpPath, noOverwrite: true};
      yield OS.File.writeAtomic(pathDest, view, options);
      test.fail("With noOverwrite, writeAtomic should have refused to overwrite file");
    } catch (err) {
      test.info("With noOverwrite, writeAtomic correctly failed");
      test.ok(err instanceof OS.File.Error, "writeAtomic correctly failed with a file error");
      test.ok(err.becauseExists, "writeAtomic file error confirmed that the file already exists");
    }
    yield reference_compare_files(pathSource, pathDest, test);
    test.ok(!(new FileUtils.File(tmpPath).exists()), "Temporary file was removed");

    // Now write a subset
    let START = 10;
    let LENGTH = 100;
    view = new Uint8Array(contents.buffer, START, LENGTH);
    bytesWritten = yield OS.File.writeAtomic(pathDest, view, {tmpPath: tmpPath});
    test.is(bytesWritten, LENGTH, "Partial write wrote the correct number of bytes");
    let array2 = yield OS.File.read(pathDest);
    let view1 = new Uint8Array(contents.buffer, START, LENGTH);
    test.is(view1.length, array2.length, "Re-read partial write with the correct number of bytes");
    for (let i = 0; i < LENGTH; ++i) {
      if (view1[i] != array2[i]) {
        test.is(view1[i], array2[i], "Offset " + i + " is correct");
      }
      test.ok(true, "Compared re-read of partial write");
    }

    // Check that writeAtomic fails if there is no tmpPath.
    // FIXME: Remove this as part of bug 793660
    try {
      yield OS.File.writeAtomic(pathDest, contents, {});
      test.fail("Without a tmpPath, writeAtomic should have failed");
    } catch (err) {
      test.ok(true, "Without a tmpPath, writeAtomic has failed as expected");
    }

    // Write strings, default encoding
    let ARBITRARY_STRING = "aeiouyâêîôûçß•";
    yield OS.File.writeAtomic(pathDest, ARBITRARY_STRING, {tmpPath: tmpPath});
    let array = yield OS.File.read(pathDest);
    let IN_STRING = (new TextDecoder()).decode(array);
    test.is(ARBITRARY_STRING, IN_STRING, "String write + read with default encoding works");

    yield OS.File.writeAtomic(pathDest, ARBITRARY_STRING, {tmpPath: tmpPath, encoding: "utf-16"});
    array = yield OS.File.read(pathDest);
    IN_STRING = (new TextDecoder("utf-16")).decode(array);
    test.is(ARBITRARY_STRING, IN_STRING, "String write + read with utf-16 encoding works");

    // Cleanup.
    OS.File.remove(pathDest);

    // Same tests with |flush: false|
    // Check that read + writeAtomic performs a correct copy
    options = {tmpPath: tmpPath, flush: false};
    optionsBackup = {tmpPath: tmpPath, flush: false};
    bytesWritten = yield OS.File.writeAtomic(pathDest, contents, options);
    test.is(contents.byteLength, bytesWritten, "Wrote the correct number of bytes (without flush)");

    // Check that options are not altered
    test.is(Object.keys(options).length, Object.keys(optionsBackup).length,
            "The number of options was not changed (without flush)");
    for (let k in options) {
      test.is(options[k], optionsBackup[k], "Option was not changed (without flush)");
    }
    yield reference_compare_files(pathSource, pathDest, test);

    // Check that temporary file was removed
    test.info("Compare complete (without flush)");
    test.ok(!(new FileUtils.File(tmpPath).exists()), "Temporary file was removed (without flush)");

    // Check that writeAtomic fails if noOverwrite is true and the destination
    // file already exists!
    view = new Uint8Array(contents.buffer, 10, 200);
    try {
      options = {tmpPath: tmpPath, noOverwrite: true, flush: false};
      yield OS.File.writeAtomic(pathDest, view, options);
      test.fail("With noOverwrite, writeAtomic should have refused to overwrite file (without flush)");
    } catch (err) {
      test.info("With noOverwrite, writeAtomic correctly failed (without flush)");
      test.ok(err instanceof OS.File.Error, "writeAtomic correctly failed with a file error (without flush)");
      test.ok(err.becauseExists, "writeAtomic file error confirmed that the file already exists (without flush)");
    }
    yield reference_compare_files(pathSource, pathDest, test);
    test.ok(!(new FileUtils.File(tmpPath).exists()), "Temporary file was removed (without flush)");

    // Now write a subset
    START = 10;
    LENGTH = 100;
    view = new Uint8Array(contents.buffer, START, LENGTH);
    bytesWritten = yield OS.File.writeAtomic(pathDest, view, {tmpPath: tmpPath, flush: false});
    test.is(bytesWritten, LENGTH, "Partial write wrote the correct number of bytes (without flush)");
    array2 = yield OS.File.read(pathDest);
    view1 = new Uint8Array(contents.buffer, START, LENGTH);
    test.is(view1.length, array2.length, "Re-read partial write with the correct number of bytes (without flush)");
    for (let i = 0; i < LENGTH; ++i) {
      if (view1[i] != array2[i]) {
        test.is(view1[i], array2[i], "Offset " + i + " is correct (without flush)");
      }
      test.ok(true, "Compared re-read of partial write (without flush)");
    }

    // Cleanup.
    OS.File.remove(pathDest);

  });
});

/**
 * Test file.{getPosition, setPosition}
 */
let test_position = maketest("position", function position(test) {
  return Task.spawn(function() {
    let file = yield OS.File.open(EXISTING_FILE);

    try {
      let stat = yield file.stat();
      test.info("Obtained file length");

      let view = new Uint8Array(stat.size);
      yield file.readTo(view);
      test.info("First batch of content read");

      let CHUNK_SIZE = 178;// An arbitrary number of bytes to read from the file
      let pos = yield file.getPosition();
      test.info("Obtained position");
      test.is(pos, view.byteLength, "getPosition returned the end of the file");
      pos = yield file.setPosition(-CHUNK_SIZE, OS.File.POS_END);
      test.info("Changed position");
      test.is(pos, view.byteLength - CHUNK_SIZE, "setPosition returned the correct position");

      let view2 = new Uint8Array(CHUNK_SIZE);
      yield file.readTo(view2);
      test.info("Read the end of the file");
      for (let i = 0; i < CHUNK_SIZE; ++i) {
        if (view2[i] != view[i + view.byteLength - CHUNK_SIZE]) {
          test.is(view2[i], view[i], "setPosition put us in the right position");
        }
      }
    } finally {
      yield file.close();
    }
  });
});

/**
 * Test OS.File.prototype.{copy, move}
 */
let test_copy = maketest("copy", function copy(test) {
  return Task.spawn(function() {
    let currentDir = yield OS.File.getCurrentDirectory();
    let pathSource = OS.Path.join(currentDir, EXISTING_FILE);
    let pathDest = OS.Path.join(OS.Constants.Path.tmpDir,
      "osfile async test 2.tmp");
    yield OS.File.copy(pathSource, pathDest);
    test.info("Copy complete");
    yield reference_compare_files(pathSource, pathDest, test);
    test.info("First compare complete");

    let pathDest2 = OS.Path.join(OS.Constants.Path.tmpDir,
      "osfile async test 3.tmp");
    yield OS.File.move(pathDest, pathDest2);
    test.info("Move complete");
    yield reference_compare_files(pathSource, pathDest2, test);
    test.info("Second compare complete");
    OS.File.remove(pathDest2);

    try {
      let field = yield OS.File.open(pathDest);
      test.fail("I should not have been able to open " + pathDest);
      file.close();
    } catch (err) {
      test.ok(err, "Could not open a file after it has been moved away " + err);
      test.ok(err instanceof OS.File.Error, "Error is an OS.File.Error");
      test.ok(err.becauseNoSuchFile, "Error mentions that the file does not exist");
    }
  });
});

/**
 * Test OS.File.{removeEmptyDir, makeDir}
 */
let test_mkdir = maketest("mkdir", function mkdir(test) {
  return Task.spawn(function() {
    const DIRNAME = "test_dir.tmp";

    // Cleanup
    yield OS.File.removeEmptyDir(DIRNAME, {ignoreAbsent: true});

    // Remove an absent directory with ignoreAbsent
    yield OS.File.removeEmptyDir(DIRNAME, {ignoreAbsent: true});
    test.ok(true, "Removing an absent directory with ignoreAbsent succeeds");

    // Remove an absent directory without ignoreAbsent
    try {
      yield OS.File.removeEmptyDir(DIRNAME);
      test.fail("Removing an absent directory without ignoreAbsent should have failed");
    } catch (err) {
      test.ok(err, "Removing an absent directory without ignoreAbsent throws the right error");
      test.ok(err instanceof OS.File.Error, "Error is an OS.File.Error");
      test.ok(err.becauseNoSuchFile, "Error mentions that the file does not exist");
    }

    // Creating a directory (should succeed)
    test.ok(true, "Creating a directory");
    yield OS.File.makeDir(DIRNAME);
    let stat = yield OS.File.stat(DIRNAME);
    test.ok(stat.isDir, "I have effectively created a directory");

    // Creating a directory with ignoreExisting (should succeed)
    try {
      yield OS.File.makeDir(DIRNAME, {ignoreExisting: true});
      test.ok(true, "Creating a directory with ignoreExisting succeeds");
    } catch(err) {
      test.ok(false, "Creating a directory with ignoreExisting fails");
    }

    // Creating a directory (should fail)
    try {
      yield OS.File.makeDir(DIRNAME);
      test.fail("Creating over an existing directory should have failed");
    } catch (err) {
      test.ok(err, "Creating over an existing directory throws the right error");
      test.ok(err instanceof OS.File.Error, "Error is an OS.File.Error");
      test.ok(err.becauseExists, "Error mentions that the file already exists");
    }

    // Remove a directory and check the result
    yield OS.File.removeEmptyDir(DIRNAME);
    test.ok(true, "Removing empty directory suceeded");
    try {
      yield OS.File.stat(DIRNAME);
      test.fail("Removing directory should have failed");
    } catch (err) {
      test.ok(err, "Directory was effectively removed");
      test.ok(err instanceof OS.File.Error, "Error is an OS.File.Error");
      test.ok(err.becauseNoSuchFile, "Error mentions that the file does not exist");
    }
  });
});

/**
 * Test OS.File.prototype.{DirectoryIterator}
 */
let test_iter = maketest("iter", function iter(test) {
  return Task.spawn(function() {
    let currentDir = yield OS.File.getCurrentDirectory();

    // Trivial walks through the directory
    test.info("Preparing iteration");
    let iterator = new OS.File.DirectoryIterator(currentDir);
    let temporary_file_name = OS.Path.join(currentDir, "empty-temporary-file.tmp");
    try {
      yield OS.File.remove(temporary_file_name);
    } catch (err) {
      // Ignore errors removing file
    }
    let allFiles1 = yield iterator.nextBatch();
    test.info("Obtained all files through nextBatch");
    test.isnot(allFiles1.length, 0, "There is at least one file");
    test.isnot(allFiles1[0].path, null, "Files have a path");

    // Ensure that we have the same entries with |reference_dir_contents|
    let referenceEntries = new Set();
    for (let entry of reference_dir_contents(currentDir)) {
      referenceEntries.add(entry);
    }
    test.is(referenceEntries.size, allFiles1.length, "All the entries in the directory have been listed");
    for (let entry of allFiles1) {
      test.ok(referenceEntries.has(entry.path), "File " + entry.path + " effectively exists");
    }

    yield iterator.close();
    test.info("Closed iterator");

    test.info("Double closing DirectoryIterator");
    iterator = new OS.File.DirectoryIterator(currentDir);
    yield iterator.close();
    yield iterator.close(); //double closing |DirectoryIterator|
    test.ok(true, "|DirectoryIterator| was closed twice successfully");

    let allFiles2 = [];
    let i = 0;
    iterator = new OS.File.DirectoryIterator(currentDir);
    yield iterator.forEach(function(entry, index) {
      test.is(i++, index, "Getting the correct index");
      allFiles2.push(entry);
    });
    test.info("Obtained all files through forEach");
    is(allFiles1.length, allFiles2.length, "Both runs returned the same number of files");
    for (let i = 0; i < allFiles1.length; ++i) {
      if (allFiles1[i].path != allFiles2[i].path) {
        test.is(allFiles1[i].path, allFiles2[i].path, "Both runs return the same files");
        break;
      }
    }

    // Testing batch iteration + whether an iteration can be stopped early
    let BATCH_LENGTH = 10;
    test.info("Getting some files through nextBatch");
    yield iterator.close();

    iterator = new OS.File.DirectoryIterator(currentDir);
    let someFiles1 = yield iterator.nextBatch(BATCH_LENGTH);
    let someFiles2 = yield iterator.nextBatch(BATCH_LENGTH);
    yield iterator.close();

    iterator = new OS.File.DirectoryIterator(currentDir);
    yield iterator.forEach(function cb(entry, index, iterator) {
      if (index < BATCH_LENGTH) {
        test.is(entry.path, someFiles1[index].path, "Both runs return the same files (part 1)");
      } else if (index < 2*BATCH_LENGTH) {
        test.is(entry.path, someFiles2[index - BATCH_LENGTH].path, "Both runs return the same files (part 2)");
      } else if (index == 2 * BATCH_LENGTH) {
        test.info("Attempting to stop asynchronous forEach");
        return iterator.close();
      } else {
        test.fail("Can we stop an asynchronous forEach? " + index);
      }
      return null;
    });

    // Ensuring that we find new files if they appear
    let file = yield OS.File.open(temporary_file_name, { write: true } );
    file.close();
    iterator = new OS.File.DirectoryIterator(currentDir);
    try {
      let files = yield iterator.nextBatch();
      is(files.length, allFiles1.length + 1, "The directory iterator has noticed the new file");
      let exists = yield iterator.exists();
      test.ok(exists, "After nextBatch, iterator detects that the directory exists");
    } finally {
      yield iterator.close();
    }

    // Ensuring that opening a non-existing directory fails consistently
    // once iteration starts.
    try {
      iterator = null;
      iterator = new OS.File.DirectoryIterator("/I do not exist");
      let exists = yield iterator.exists();
      test.ok(!exists, "Before any iteration, iterator detects that the directory doesn't exist");
      let exn = null;
      try {
        yield iterator.next();
      } catch (ex if ex instanceof OS.File.Error && ex.becauseNoSuchFile) {
        exn = ex;
        let exists = yield iterator.exists();
        test.ok(!exists, "After one iteration, iterator detects that the directory doesn't exist");
      }
      test.ok(exn, "Iterating through a directory that does not exist has failed with becauseNoSuchFile");
    } finally {
      if (iterator) {
        iterator.close();
      }
    }
    test.ok(!!iterator, "The directory iterator for a non-existing directory was correctly created");
  });
});

/**
 * Test OS.File.prototype.{exists}
 */
let test_exists = maketest("exists", function exists(test) {
  return Task.spawn(function() {
    let fileExists = yield OS.File.exists(EXISTING_FILE);
    test.ok(fileExists, "file exists");
    fileExists = yield OS.File.exists(EXISTING_FILE + ".tmp");
    test.ok(!fileExists, "file does not exists");
  });
});

/**
 * Test changes to OS.Shared.DEBUG flag.
 */
let test_debug = maketest("debug", function debug(test) {
  return Task.spawn(function() {
    function testSetDebugPref (pref) {
      try {
        Services.prefs.setBoolPref("toolkit.osfile.log", pref);
      } catch (x) {
        test.fail("Setting OS.Shared.DEBUG to " + pref +
          " should not cause error.");
      } finally {
        test.is(OS.Shared.DEBUG, pref, "OS.Shared.DEBUG is set correctly.");
      }
    }
    testSetDebugPref(true);
    let workerDEBUG = yield OS.File.GET_DEBUG();
    test.is(workerDEBUG, true, "Worker's DEBUG is set.");
    testSetDebugPref(false);
    workerDEBUG = yield OS.File.GET_DEBUG();
    test.is(workerDEBUG, false, "Worker's DEBUG is unset.");
  });
});

/**
 * Test logging in the main thread with set OS.Shared.DEBUG and
 * OS.Shared.TEST flags.
 */
let test_debug_test = maketest("debug_test", function debug_test(test) {
  return Task.spawn(function () {
    // Create a console listener.
    let consoleListener = {
      observe: function (aMessage) {
        // Ignore unexpected messages.
        if (!(aMessage instanceof Components.interfaces.nsIConsoleMessage)) {
          return;
        }
        if (aMessage.message.indexOf("TEST OS") < 0) {
          return;
        }
        test.ok(true, "DEBUG TEST messages are logged correctly.")
      }
    };
    // Set/Unset OS.Shared.DEBUG, OS.Shared.TEST and the console listener.
    function toggleDebugTest (pref) {
      OS.Shared.DEBUG = pref;
      OS.Shared.TEST = pref;
      Services.console[pref ? "registerListener" : "unregisterListener"](
        consoleListener);
    }
    // Save original DEBUG value.
    let originalPref = OS.Shared.DEBUG;
    toggleDebugTest(true);
    // Execution of OS.File.exist method will trigger OS.File.LOG several times.
    let fileExists = yield OS.File.exists(EXISTING_FILE);
    toggleDebugTest(false);
    // Restore DEBUG to its original.
    OS.Shared.DEBUG = originalPref;
  });
});

/**
 * Test logging of file descriptors leaks.
 */
let test_system_shutdown = maketest("system_shutdown", function system_shutdown(test) {
  return Task.spawn(function () {
    // Save original DEBUG value.
    let originalDebug = OS.Shared.DEBUG;
    // Create a console listener.
    function getConsoleListener(resource) {
      let consoleListener = {
        observe: function (aMessage) {
          // Ignore unexpected messages.
          if (!(aMessage instanceof Components.interfaces.nsIConsoleMessage)) {
            return;
          }
          if (aMessage.message.indexOf("TEST OS Controller WARNING") < 0) {
            return;
          }
          test.ok(aMessage.message.indexOf("WARNING: File descriptors leaks " +
            "detected.") >= 0, "File descriptors leaks are logged correctly.");
          test.ok(aMessage.message.indexOf(resource) >= 0,
            "Leaked resource is correctly listed in the log.");
          toggleDebugTest(false, resource, consoleListener);
        }
      };
      return consoleListener;
    }
    // Set/Unset testing flags and Services.console listener.
    function toggleDebugTest(startDebug, resource, consoleListener) {
      Services.console[startDebug ? "registerListener" : "unregisterListener"](
        consoleListener || getConsoleListener(resource));
      OS.Shared.TEST = startDebug;
      // If pref is false, restore DEBUG to its original.
      OS.Shared.DEBUG = startDebug || originalDebug;
    }

    let currentDir = yield OS.File.getCurrentDirectory();
    let iterator = new OS.File.DirectoryIterator(currentDir);
    toggleDebugTest(true, currentDir);
    Services.obs.notifyObservers(null, "test.osfile.web-workers-shutdown",
      null);
    yield iterator.close();

    let openedFile = yield OS.File.open(EXISTING_FILE);
    toggleDebugTest(true, EXISTING_FILE);
    Services.obs.notifyObservers(null, "test.osfile.web-workers-shutdown",
      null);
    yield openedFile.close();
  });
});

/**
 * Test optional duration reporting that can be used for telemetry.
 */
let test_duration = maketest("duration", function duration(test) {
  return Task.spawn(function() {
    // Options structure passed to a OS.File copy method.
    let copyOptions = {
      // This field should be overridden with the actual duration
      // measurement.
      outExecutionDuration: null
    };
    let currentDir = yield OS.File.getCurrentDirectory();
    let pathSource = OS.Path.join(currentDir, EXISTING_FILE);
    let copyFile = pathSource + ".bak";
    let testOptions = function testOptions(options) {
      test.info("Gathered method duration time: " +
        options.outExecutionDuration + " MS");
      // Making sure that duration was updated.
      test.ok(typeof options.outExecutionDuration === "number" &&
        options.outExecutionDuration >= 0,
        "Operation duration time was updated correctly with a numeric value.");
    };
    // Testing duration of OS.File.copy.
    yield OS.File.copy(pathSource, copyFile, copyOptions);
    testOptions(copyOptions);
    yield OS.File.remove(copyFile);

    // Trying an operation where options are cloned.
    let pathDest = OS.Path.join(OS.Constants.Path.tmpDir,
      "osfile async test read writeAtomic.tmp");
    let tmpPath = pathDest + ".tmp";
    let contents = yield OS.File.read(pathSource);
    // Options structure passed to a OS.File writeAtomic method.
    let writeAtomicOptions = {
      // This field should be first initialized with the actual
      // duration measurement then progressively incremented.
      outExecutionDuration: null,
      tmpPath: tmpPath
    };
    yield OS.File.writeAtomic(pathDest, contents, writeAtomicOptions);
    testOptions(writeAtomicOptions);
    yield OS.File.remove(pathDest);

    test.info("Ensuring that we can use outExecutionDuration to accumulate durations");

    let ARBITRARY_BASE_DURATION = 5;
    copyOptions = {
      // This field should now be incremented with the actual duration
      // measurement.
      outExecutionDuration: ARBITRARY_BASE_DURATION
    };
    let backupDuration = ARBITRARY_BASE_DURATION;
    // Testing duration of OS.File.copy.
    yield OS.File.copy(pathSource, copyFile, copyOptions);
    test.ok(copyOptions.outExecutionDuration >= backupDuration);

    backupDuration = copyOptions.outExecutionDuration;
    yield OS.File.remove(copyFile, copyOptions);
    test.ok(copyOptions.outExecutionDuration >= backupDuration);

    // Trying an operation where options are cloned.
    // Options structure passed to a OS.File writeAtomic method.
    writeAtomicOptions = {
      // This field should be overridden with the actual duration
      // measurement.
      outExecutionDuration: copyOptions.outExecutionDuration,
      tmpPath: tmpPath
    };
    backupDuration = writeAtomicOptions.outExecutionDuration;
    yield OS.File.writeAtomic(pathDest, contents, writeAtomicOptions);
    test.ok(copyOptions.outExecutionDuration >= backupDuration);
    OS.File.remove(pathDest);

    // Testing an operation that doesn't take arguments at all
    let file = yield OS.File.open(pathSource);
    yield file.stat();
    yield file.close();
  });
});
