1 files changed, 775 insertions, 0 deletions
diff --git a/netwerk/test/unit/test_backgroundfilesaver.js b/netwerk/test/unit/test_backgroundfilesaver.js
new file mode 100644
index 0000000000..696884f356
--- /dev/null
+++ b/netwerk/test/unit/test_backgroundfilesaver.js
@@ -0,0 +1,775 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests components that implement nsIBackgroundFileSaver.
+ */
+
+////////////////////////////////////////////////////////////////////////////////
+//// Globals
+
+"use strict";
+
+ChromeUtils.defineModuleGetter(
+  this,
+  "FileUtils",
+  "resource://gre/modules/FileUtils.jsm"
+);
+ChromeUtils.defineModuleGetter(
+  this,
+  "NetUtil",
+  "resource://gre/modules/NetUtil.jsm"
+);
+ChromeUtils.defineModuleGetter(
+  this,
+  "FileTestUtils",
+  "resource://testing-common/FileTestUtils.jsm"
+);
+
+const BackgroundFileSaverOutputStream = Components.Constructor(
+  "@mozilla.org/network/background-file-saver;1?mode=outputstream",
+  "nsIBackgroundFileSaver"
+);
+
+const BackgroundFileSaverStreamListener = Components.Constructor(
+  "@mozilla.org/network/background-file-saver;1?mode=streamlistener",
+  "nsIBackgroundFileSaver"
+);
+
+const StringInputStream = Components.Constructor(
+  "@mozilla.org/io/string-input-stream;1",
+  "nsIStringInputStream",
+  "setData"
+);
+
+const REQUEST_SUSPEND_AT = 1024 * 1024 * 4;
+const TEST_DATA_SHORT = "This test string is written to the file.";
+const TEST_FILE_NAME_1 = "test-backgroundfilesaver-1.txt";
+const TEST_FILE_NAME_2 = "test-backgroundfilesaver-2.txt";
+const TEST_FILE_NAME_3 = "test-backgroundfilesaver-3.txt";
+
+// A map of test data length to the expected SHA-256 hashes
+const EXPECTED_HASHES = {
+  // No data
+  0: "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+  // TEST_DATA_SHORT
+  40: "f37176b690e8744ee990a206c086cba54d1502aa2456c3b0c84ef6345d72a192",
+  // TEST_DATA_SHORT + TEST_DATA_SHORT
+  80: "780c0e91f50bb7ec922cc11e16859e6d5df283c0d9470f61772e3d79f41eeb58",
+  // TEST_DATA_LONG
+  4718592: "372cb9e5ce7b76d3e2a5042e78aa72dcf973e659a262c61b7ff51df74b36767b",
+  // TEST_DATA_LONG + TEST_DATA_LONG
+  9437184: "693e4f8c6855a6fed4f5f9370d12cc53105672f3ff69783581e7d925984c41d3",
+};
+
+const gTextDecoder = new TextDecoder();
+
+// Generate a long string of data in a moderately fast way.
+const TEST_256_CHARS = new Array(257).join("-");
+const DESIRED_LENGTH = REQUEST_SUSPEND_AT * 1.125;
+const TEST_DATA_LONG = new Array(1 + DESIRED_LENGTH / 256).join(TEST_256_CHARS);
+Assert.equal(TEST_DATA_LONG.length, DESIRED_LENGTH);
+
+/**
+ * Returns a reference to a temporary file that is guaranteed not to exist and
+ * is cleaned up later. See FileTestUtils.getTempFile for details.
+ */
+function getTempFile(leafName) {
+  return FileTestUtils.getTempFile(leafName);
+}
+
+/**
+ * Helper function for converting a binary blob to its hex equivalent.
+ *
+ * @param str
+ *        String possibly containing non-printable chars.
+ * @return A hex-encoded string.
+ */
+function toHex(str) {
+  var hex = "";
+  for (var i = 0; i < str.length; i++) {
+    hex += ("0" + str.charCodeAt(i).toString(16)).slice(-2);
+  }
+  return hex;
+}
+
+/**
+ * Ensures that the given file contents are equal to the given string.
+ *
+ * @param aFile
+ *        nsIFile whose contents should be verified.
+ * @param aExpectedContents
+ *        String containing the octets that are expected in the file.
+ *
+ * @return {Promise}
+ * @resolves When the operation completes.
+ * @rejects Never.
+ */
+function promiseVerifyContents(aFile, aExpectedContents) {
+  return new Promise(resolve => {
+    NetUtil.asyncFetch(
+      {
+        uri: NetUtil.newURI(aFile),
+        loadUsingSystemPrincipal: true,
+      },
+      function(aInputStream, aStatus) {
+        Assert.ok(Components.isSuccessCode(aStatus));
+        let contents = NetUtil.readInputStreamToString(
+          aInputStream,
+          aInputStream.available()
+        );
+        if (contents.length <= TEST_DATA_SHORT.length * 2) {
+          Assert.equal(contents, aExpectedContents);
+        } else {
+          // Do not print the entire content string to the test log.
+          Assert.equal(contents.length, aExpectedContents.length);
+          Assert.ok(contents == aExpectedContents);
+        }
+        resolve();
+      }
+    );
+  });
+}
+
+/**
+ * Waits for the given saver object to complete.
+ *
+ * @param aSaver
+ *        The saver, with the output stream or a stream listener implementation.
+ * @param aOnTargetChangeFn
+ *        Optional callback invoked with the target file name when it changes.
+ *
+ * @return {Promise}
+ * @resolves When onSaveComplete is called with a success code.
+ * @rejects With an exception, if onSaveComplete is called with a failure code.
+ */
+function promiseSaverComplete(aSaver, aOnTargetChangeFn) {
+  return new Promise((resolve, reject) => {
+    aSaver.observer = {
+      onTargetChange: function BFSO_onSaveComplete(aSaver, aTarget) {
+        if (aOnTargetChangeFn) {
+          aOnTargetChangeFn(aTarget);
+        }
+      },
+      onSaveComplete: function BFSO_onSaveComplete(aSaver, aStatus) {
+        if (Components.isSuccessCode(aStatus)) {
+          resolve();
+        } else {
+          reject(new Components.Exception("Saver failed.", aStatus));
+        }
+      },
+    };
+  });
+}
+
+/**
+ * Feeds a string to a BackgroundFileSaverOutputStream.
+ *
+ * @param aSourceString
+ *        The source data to copy.
+ * @param aSaverOutputStream
+ *        The BackgroundFileSaverOutputStream to feed.
+ * @param aCloseWhenDone
+ *        If true, the output stream will be closed when the copy finishes.
+ *
+ * @return {Promise}
+ * @resolves When the copy completes with a success code.
+ * @rejects With an exception, if the copy fails.
+ */
+function promiseCopyToSaver(aSourceString, aSaverOutputStream, aCloseWhenDone) {
+  return new Promise((resolve, reject) => {
+    let inputStream = new StringInputStream(
+      aSourceString,
+      aSourceString.length
+    );
+    let copier = Cc[
+      "@mozilla.org/network/async-stream-copier;1"
+    ].createInstance(Ci.nsIAsyncStreamCopier);
+    copier.init(
+      inputStream,
+      aSaverOutputStream,
+      null,
+      false,
+      true,
+      0x8000,
+      true,
+      aCloseWhenDone
+    );
+    copier.asyncCopy(
+      {
+        onStartRequest() {},
+        onStopRequest(aRequest, aStatusCode) {
+          if (Components.isSuccessCode(aStatusCode)) {
+            resolve();
+          } else {
+            reject(new Components.Exception(aStatusCode));
+          }
+        },
+      },
+      null
+    );
+  });
+}
+
+/**
+ * Feeds a string to a BackgroundFileSaverStreamListener.
+ *
+ * @param aSourceString
+ *        The source data to copy.
+ * @param aSaverStreamListener
+ *        The BackgroundFileSaverStreamListener to feed.
+ * @param aCloseWhenDone
+ *        If true, the output stream will be closed when the copy finishes.
+ *
+ * @return {Promise}
+ * @resolves When the operation completes with a success code.
+ * @rejects With an exception, if the operation fails.
+ */
+function promisePumpToSaver(
+  aSourceString,
+  aSaverStreamListener,
+  aCloseWhenDone
+) {
+  return new Promise((resolve, reject) => {
+    aSaverStreamListener.QueryInterface(Ci.nsIStreamListener);
+    let inputStream = new StringInputStream(
+      aSourceString,
+      aSourceString.length
+    );
+    let pump = Cc["@mozilla.org/network/input-stream-pump;1"].createInstance(
+      Ci.nsIInputStreamPump
+    );
+    pump.init(inputStream, 0, 0, true);
+    pump.asyncRead({
+      onStartRequest: function PPTS_onStartRequest(aRequest) {
+        aSaverStreamListener.onStartRequest(aRequest);
+      },
+      onStopRequest: function PPTS_onStopRequest(aRequest, aStatusCode) {
+        aSaverStreamListener.onStopRequest(aRequest, aStatusCode);
+        if (Components.isSuccessCode(aStatusCode)) {
+          resolve();
+        } else {
+          reject(new Components.Exception(aStatusCode));
+        }
+      },
+      onDataAvailable: function PPTS_onDataAvailable(
+        aRequest,
+        aInputStream,
+        aOffset,
+        aCount
+      ) {
+        aSaverStreamListener.onDataAvailable(
+          aRequest,
+          aInputStream,
+          aOffset,
+          aCount
+        );
+      },
+    });
+  });
+}
+
+var gStillRunning = true;
+
+////////////////////////////////////////////////////////////////////////////////
+//// Tests
+
+add_task(function test_setup() {
+  // Wait 10 minutes, that is half of the external xpcshell timeout.
+  do_timeout(10 * 60 * 1000, function() {
+    if (gStillRunning) {
+      do_throw("Test timed out.");
+    }
+  });
+});
+
+add_task(async function test_normal() {
+  // This test demonstrates the most basic use case.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  // Create the object implementing the output stream.
+  let saver = new BackgroundFileSaverOutputStream();
+
+  // Set up callbacks for completion and target file name change.
+  let receivedOnTargetChange = false;
+  function onTargetChange(aTarget) {
+    Assert.ok(destFile.equals(aTarget));
+    receivedOnTargetChange = true;
+  }
+  let completionPromise = promiseSaverComplete(saver, onTargetChange);
+
+  // Set the target file.
+  saver.setTarget(destFile, false);
+
+  // Write some data and close the output stream.
+  await promiseCopyToSaver(TEST_DATA_SHORT, saver, true);
+
+  // Indicate that we are ready to finish, and wait for a successful callback.
+  saver.finish(Cr.NS_OK);
+  await completionPromise;
+
+  // Only after we receive the completion notification, we can also be sure that
+  // we've received the target file name change notification before it.
+  Assert.ok(receivedOnTargetChange);
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(async function test_combinations() {
+  let initialFile = getTempFile(TEST_FILE_NAME_1);
+  let renamedFile = getTempFile(TEST_FILE_NAME_2);
+
+  // Keep track of the current file.
+  let currentFile = null;
+  function onTargetChange(aTarget) {
+    currentFile = null;
+    info("Target file changed to: " + aTarget.leafName);
+    currentFile = aTarget;
+  }
+
+  // Tests various combinations of events and behaviors for both the stream
+  // listener and the output stream implementations.
+  for (let testFlags = 0; testFlags < 32; testFlags++) {
+    let keepPartialOnFailure = !!(testFlags & 1);
+    let renameAtSomePoint = !!(testFlags & 2);
+    let cancelAtSomePoint = !!(testFlags & 4);
+    let useStreamListener = !!(testFlags & 8);
+    let useLongData = !!(testFlags & 16);
+
+    let startTime = Date.now();
+    info(
+      "Starting keepPartialOnFailure = " +
+        keepPartialOnFailure +
+        ", renameAtSomePoint = " +
+        renameAtSomePoint +
+        ", cancelAtSomePoint = " +
+        cancelAtSomePoint +
+        ", useStreamListener = " +
+        useStreamListener +
+        ", useLongData = " +
+        useLongData
+    );
+
+    // Create the object and register the observers.
+    currentFile = null;
+    let saver = useStreamListener
+      ? new BackgroundFileSaverStreamListener()
+      : new BackgroundFileSaverOutputStream();
+    saver.enableSha256();
+    let completionPromise = promiseSaverComplete(saver, onTargetChange);
+
+    // Start feeding the first chunk of data to the saver.  In case we are using
+    // the stream listener, we only write one chunk.
+    let testData = useLongData ? TEST_DATA_LONG : TEST_DATA_SHORT;
+    let feedPromise = useStreamListener
+      ? promisePumpToSaver(testData + testData, saver)
+      : promiseCopyToSaver(testData, saver, false);
+
+    // Set a target output file.
+    saver.setTarget(initialFile, keepPartialOnFailure);
+
+    // Wait for the first chunk of data to be copied.
+    await feedPromise;
+
+    if (renameAtSomePoint) {
+      saver.setTarget(renamedFile, keepPartialOnFailure);
+    }
+
+    if (cancelAtSomePoint) {
+      saver.finish(Cr.NS_ERROR_FAILURE);
+    }
+
+    // Feed the second chunk of data to the saver.
+    if (!useStreamListener) {
+      await promiseCopyToSaver(testData, saver, true);
+    }
+
+    // Wait for completion, and ensure we succeeded or failed as expected.
+    if (!cancelAtSomePoint) {
+      saver.finish(Cr.NS_OK);
+    }
+    try {
+      await completionPromise;
+      if (cancelAtSomePoint) {
+        do_throw("Failure expected.");
+      }
+    } catch (ex) {
+      if (!cancelAtSomePoint || ex.result != Cr.NS_ERROR_FAILURE) {
+        throw ex;
+      }
+    }
+
+    if (!cancelAtSomePoint) {
+      // In this case, the file must exist.
+      Assert.ok(currentFile.exists());
+      let expectedContents = testData + testData;
+      await promiseVerifyContents(currentFile, expectedContents);
+      Assert.equal(
+        EXPECTED_HASHES[expectedContents.length],
+        toHex(saver.sha256Hash)
+      );
+      currentFile.remove(false);
+
+      // If the target was really renamed, the old file should not exist.
+      if (renamedFile.equals(currentFile)) {
+        Assert.ok(!initialFile.exists());
+      }
+    } else if (!keepPartialOnFailure) {
+      // In this case, the file must not exist.
+      Assert.ok(!initialFile.exists());
+      Assert.ok(!renamedFile.exists());
+    } else {
+      // In this case, the file may or may not exist, because canceling can
+      // interrupt the asynchronous operation at any point, even before the file
+      // has been created for the first time.
+      if (initialFile.exists()) {
+        initialFile.remove(false);
+      }
+      if (renamedFile.exists()) {
+        renamedFile.remove(false);
+      }
+    }
+
+    info("Test case completed in " + (Date.now() - startTime) + " ms.");
+  }
+});
+
+add_task(async function test_setTarget_after_close_stream() {
+  // This test checks the case where we close the output stream before we call
+  // the setTarget method.  All the data should be buffered and written anyway.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  // Test the case where the file does not already exists first, then the case
+  // where the file already exists.
+  for (let i = 0; i < 2; i++) {
+    let saver = new BackgroundFileSaverOutputStream();
+    saver.enableSha256();
+    let completionPromise = promiseSaverComplete(saver);
+
+    // Copy some data to the output stream of the file saver.  This data must
+    // be shorter than the internal component's pipe buffer for the test to
+    // succeed, because otherwise the test would block waiting for the write to
+    // complete.
+    await promiseCopyToSaver(TEST_DATA_SHORT, saver, true);
+
+    // Set the target file and wait for the output to finish.
+    saver.setTarget(destFile, false);
+    saver.finish(Cr.NS_OK);
+    await completionPromise;
+
+    // Verify results.
+    await promiseVerifyContents(destFile, TEST_DATA_SHORT);
+    Assert.equal(
+      EXPECTED_HASHES[TEST_DATA_SHORT.length],
+      toHex(saver.sha256Hash)
+    );
+  }
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(async function test_setTarget_fast() {
+  // This test checks a fast rename of the target file.
+  let destFile1 = getTempFile(TEST_FILE_NAME_1);
+  let destFile2 = getTempFile(TEST_FILE_NAME_2);
+  let saver = new BackgroundFileSaverOutputStream();
+  let completionPromise = promiseSaverComplete(saver);
+
+  // Set the initial name after the stream is closed, then rename immediately.
+  await promiseCopyToSaver(TEST_DATA_SHORT, saver, true);
+  saver.setTarget(destFile1, false);
+  saver.setTarget(destFile2, false);
+
+  // Wait for all the operations to complete.
+  saver.finish(Cr.NS_OK);
+  await completionPromise;
+
+  // Verify results and clean up.
+  Assert.ok(!destFile1.exists());
+  await promiseVerifyContents(destFile2, TEST_DATA_SHORT);
+  destFile2.remove(false);
+});
+
+add_task(async function test_setTarget_multiple() {
+  // This test checks multiple renames of the target file.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+  let saver = new BackgroundFileSaverOutputStream();
+  let completionPromise = promiseSaverComplete(saver);
+
+  // Rename both before and after the stream is closed.
+  saver.setTarget(getTempFile(TEST_FILE_NAME_2), false);
+  saver.setTarget(getTempFile(TEST_FILE_NAME_3), false);
+  await promiseCopyToSaver(TEST_DATA_SHORT, saver, true);
+  saver.setTarget(getTempFile(TEST_FILE_NAME_2), false);
+  saver.setTarget(destFile, false);
+
+  // Wait for all the operations to complete.
+  saver.finish(Cr.NS_OK);
+  await completionPromise;
+
+  // Verify results and clean up.
+  Assert.ok(!getTempFile(TEST_FILE_NAME_2).exists());
+  Assert.ok(!getTempFile(TEST_FILE_NAME_3).exists());
+  await promiseVerifyContents(destFile, TEST_DATA_SHORT);
+  destFile.remove(false);
+});
+
+add_task(async function test_enableAppend() {
+  // This test checks append mode with hashing disabled.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  // Test the case where the file does not already exists first, then the case
+  // where the file already exists.
+  for (let i = 0; i < 2; i++) {
+    let saver = new BackgroundFileSaverOutputStream();
+    saver.enableAppend();
+    let completionPromise = promiseSaverComplete(saver);
+
+    saver.setTarget(destFile, false);
+    await promiseCopyToSaver(TEST_DATA_LONG, saver, true);
+
+    saver.finish(Cr.NS_OK);
+    await completionPromise;
+
+    // Verify results.
+    let expectedContents =
+      i == 0 ? TEST_DATA_LONG : TEST_DATA_LONG + TEST_DATA_LONG;
+    await promiseVerifyContents(destFile, expectedContents);
+  }
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(async function test_enableAppend_setTarget_fast() {
+  // This test checks a fast rename of the target file in append mode.
+  let destFile1 = getTempFile(TEST_FILE_NAME_1);
+  let destFile2 = getTempFile(TEST_FILE_NAME_2);
+
+  // Test the case where the file does not already exists first, then the case
+  // where the file already exists.
+  for (let i = 0; i < 2; i++) {
+    let saver = new BackgroundFileSaverOutputStream();
+    saver.enableAppend();
+    let completionPromise = promiseSaverComplete(saver);
+
+    await promiseCopyToSaver(TEST_DATA_SHORT, saver, true);
+
+    // The first time, we start appending to the first file and rename to the
+    // second file.  The second time, we start appending to the second file,
+    // that was created the first time, and rename back to the first file.
+    let firstFile = i == 0 ? destFile1 : destFile2;
+    let secondFile = i == 0 ? destFile2 : destFile1;
+    saver.setTarget(firstFile, false);
+    saver.setTarget(secondFile, false);
+
+    saver.finish(Cr.NS_OK);
+    await completionPromise;
+
+    // Verify results.
+    Assert.ok(!firstFile.exists());
+    let expectedContents =
+      i == 0 ? TEST_DATA_SHORT : TEST_DATA_SHORT + TEST_DATA_SHORT;
+    await promiseVerifyContents(secondFile, expectedContents);
+  }
+
+  // Clean up.
+  destFile1.remove(false);
+});
+
+add_task(async function test_enableAppend_hash() {
+  // This test checks append mode, also verifying that the computed hash
+  // includes the contents of the existing data.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  // Test the case where the file does not already exists first, then the case
+  // where the file already exists.
+  for (let i = 0; i < 2; i++) {
+    let saver = new BackgroundFileSaverOutputStream();
+    saver.enableAppend();
+    saver.enableSha256();
+    let completionPromise = promiseSaverComplete(saver);
+
+    saver.setTarget(destFile, false);
+    await promiseCopyToSaver(TEST_DATA_LONG, saver, true);
+
+    saver.finish(Cr.NS_OK);
+    await completionPromise;
+
+    // Verify results.
+    let expectedContents =
+      i == 0 ? TEST_DATA_LONG : TEST_DATA_LONG + TEST_DATA_LONG;
+    await promiseVerifyContents(destFile, expectedContents);
+    Assert.equal(
+      EXPECTED_HASHES[expectedContents.length],
+      toHex(saver.sha256Hash)
+    );
+  }
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(async function test_finish_only() {
+  // This test checks creating the object and doing nothing.
+  let saver = new BackgroundFileSaverOutputStream();
+  function onTargetChange(aTarget) {
+    do_throw("Should not receive the onTargetChange notification.");
+  }
+  let completionPromise = promiseSaverComplete(saver, onTargetChange);
+  saver.finish(Cr.NS_OK);
+  await completionPromise;
+});
+
+add_task(async function test_empty() {
+  // This test checks we still create an empty file when no data is fed.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  let saver = new BackgroundFileSaverOutputStream();
+  let completionPromise = promiseSaverComplete(saver);
+
+  saver.setTarget(destFile, false);
+  await promiseCopyToSaver("", saver, true);
+
+  saver.finish(Cr.NS_OK);
+  await completionPromise;
+
+  // Verify results.
+  Assert.ok(destFile.exists());
+  Assert.equal(destFile.fileSize, 0);
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(async function test_empty_hash() {
+  // This test checks the hash of an empty file, both in normal and append mode.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  // Test normal mode first, then append mode.
+  for (let i = 0; i < 2; i++) {
+    let saver = new BackgroundFileSaverOutputStream();
+    if (i == 1) {
+      saver.enableAppend();
+    }
+    saver.enableSha256();
+    let completionPromise = promiseSaverComplete(saver);
+
+    saver.setTarget(destFile, false);
+    await promiseCopyToSaver("", saver, true);
+
+    saver.finish(Cr.NS_OK);
+    await completionPromise;
+
+    // Verify results.
+    Assert.equal(destFile.fileSize, 0);
+    Assert.equal(EXPECTED_HASHES[0], toHex(saver.sha256Hash));
+  }
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(async function test_invalid_hash() {
+  let saver = new BackgroundFileSaverStreamListener();
+  let completionPromise = promiseSaverComplete(saver);
+  // We shouldn't be able to get the hash if hashing hasn't been enabled
+  try {
+    saver.sha256Hash;
+    do_throw("Shouldn't be able to get hash if hashing not enabled");
+  } catch (ex) {
+    if (ex.result != Cr.NS_ERROR_NOT_AVAILABLE) {
+      throw ex;
+    }
+  }
+  // Enable hashing, but don't feed any data to saver
+  saver.enableSha256();
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+  saver.setTarget(destFile, false);
+  // We don't wait on promiseSaverComplete, so the hash getter can run before
+  // or after onSaveComplete is called. However, the expected behavior is the
+  // same in both cases since the hash is only valid when the save completes
+  // successfully.
+  saver.finish(Cr.NS_ERROR_FAILURE);
+  try {
+    saver.sha256Hash;
+    do_throw("Shouldn't be able to get hash if save did not succeed");
+  } catch (ex) {
+    if (ex.result != Cr.NS_ERROR_NOT_AVAILABLE) {
+      throw ex;
+    }
+  }
+  // Wait for completion so that the worker thread finishes dealing with the
+  // target file. We expect it to fail.
+  try {
+    await completionPromise;
+    do_throw("completionPromise should throw");
+  } catch (ex) {
+    if (ex.result != Cr.NS_ERROR_FAILURE) {
+      throw ex;
+    }
+  }
+});
+
+add_task(async function test_signature() {
+  // Check that we get a signature if the saver is finished.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  let saver = new BackgroundFileSaverOutputStream();
+  let completionPromise = promiseSaverComplete(saver);
+
+  try {
+    saver.signatureInfo;
+    do_throw("Can't get signature if saver is not complete");
+  } catch (ex) {
+    if (ex.result != Cr.NS_ERROR_NOT_AVAILABLE) {
+      throw ex;
+    }
+  }
+
+  saver.enableSignatureInfo();
+  saver.setTarget(destFile, false);
+  await promiseCopyToSaver(TEST_DATA_SHORT, saver, true);
+
+  saver.finish(Cr.NS_OK);
+  await completionPromise;
+  await promiseVerifyContents(destFile, TEST_DATA_SHORT);
+
+  // signatureInfo is an empty nsIArray
+  Assert.equal(0, saver.signatureInfo.length);
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(async function test_signature_not_enabled() {
+  // Check that we get a signature if the saver is finished on Windows.
+  let destFile = getTempFile(TEST_FILE_NAME_1);
+
+  let saver = new BackgroundFileSaverOutputStream();
+  let completionPromise = promiseSaverComplete(saver);
+  saver.setTarget(destFile, false);
+  await promiseCopyToSaver(TEST_DATA_SHORT, saver, true);
+
+  saver.finish(Cr.NS_OK);
+  await completionPromise;
+  try {
+    saver.signatureInfo;
+    do_throw("Can't get signature if not enabled");
+  } catch (ex) {
+    if (ex.result != Cr.NS_ERROR_NOT_AVAILABLE) {
+      throw ex;
+    }
+  }
+
+  // Clean up.
+  destFile.remove(false);
+});
+
+add_task(function test_teardown() {
+  gStillRunning = false;
+});