1 files changed, 126 insertions, 0 deletions
diff --git a/browser/components/downloads/test/browser/browser_download_overwrite.js b/browser/components/downloads/test/browser/browser_download_overwrite.js
new file mode 100644
index 0000000000..7be16aa565
--- /dev/null
+++ b/browser/components/downloads/test/browser/browser_download_overwrite.js
@@ -0,0 +1,126 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_ROOT = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://example.com"
+);
+
+var MockFilePicker = SpecialPowers.MockFilePicker;
+MockFilePicker.init(window);
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/toolkit/content/tests/browser/common/mockTransfer.js",
+  this
+);
+
+add_setup(async function () {
+  // head.js has helpers that write to a nice unique file we can use.
+  await createDownloadedFile(gTestTargetFile.path, "Hello.\n");
+  ok(gTestTargetFile.exists(), "We created a test file.");
+
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.download.always_ask_before_handling_new_types", false],
+      ["browser.download.useDownloadDir", false],
+    ],
+  });
+  // Set up the file picker.
+  let destDir = gTestTargetFile.parent;
+
+  MockFilePicker.displayDirectory = destDir;
+  MockFilePicker.showCallback = function (fp) {
+    MockFilePicker.setFiles([gTestTargetFile]);
+    return MockFilePicker.returnOK;
+  };
+  registerCleanupFunction(function () {
+    MockFilePicker.cleanup();
+    if (gTestTargetFile.exists()) {
+      gTestTargetFile.remove(false);
+    }
+  });
+});
+
+// If we download a file and the user accepts overwriting an existing one,
+// we shouldn't first delete that file before moving the .part file into
+// place.
+add_task(async function test_overwrite_does_not_delete_first() {
+  let unregisteredTransfer = false;
+  let transferCompletePromise = new Promise(resolve => {
+    mockTransferCallback = resolve;
+  });
+  mockTransferRegisterer.register();
+
+  registerCleanupFunction(function () {
+    if (!unregisteredTransfer) {
+      mockTransferRegisterer.unregister();
+    }
+  });
+
+  // Now try and download a thing to the file:
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      opening: TEST_ROOT + "foo.txt",
+      waitForLoad: false,
+      waitForStateStop: true,
+    },
+    async function () {
+      ok(await transferCompletePromise, "download should succeed");
+      ok(
+        gTestTargetFile.exists(),
+        "File should still exist and not have been deleted."
+      );
+      // Note: the download transfer is fake so data won't have been written to
+      // the file, so we can't verify that the download actually overwrites data
+      // like this.
+      mockTransferRegisterer.unregister();
+      unregisteredTransfer = true;
+    }
+  );
+});
+
+// If we download a file and the user accepts overwriting an existing one,
+// we should successfully overwrite its contents.
+add_task(async function test_overwrite_works() {
+  let publicDownloads = await Downloads.getList(Downloads.PUBLIC);
+  // First ensure we catch the download finishing.
+  let downloadFinishedPromise = new Promise(resolve => {
+    publicDownloads.addView({
+      onDownloadChanged(download) {
+        info("Download changed!");
+        if (download.succeeded || download.error) {
+          info("Download succeeded or errored");
+          publicDownloads.removeView(this);
+          publicDownloads.removeFinished();
+          resolve(download);
+        }
+      },
+    });
+  });
+  // Now try and download a thing to the file:
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      opening: TEST_ROOT + "foo.txt",
+      waitForLoad: false,
+      waitForStateStop: true,
+    },
+    async function () {
+      info("wait for download to finish");
+      let download = await downloadFinishedPromise;
+      ok(download.succeeded, "Download should succeed");
+      ok(
+        gTestTargetFile.exists(),
+        "File should still exist and not have been deleted."
+      );
+      let contents = new TextDecoder().decode(
+        await IOUtils.read(gTestTargetFile.path)
+      );
+      info("Got: " + contents);
+      ok(contents.startsWith("Dummy"), "The file was overwritten.");
+    }
+  );
+});