1 files changed, 120 insertions, 0 deletions
diff --git a/browser/components/firefoxview/tests/browser/browser_dragDrop_after_opening_fxViewTab.js b/browser/components/firefoxview/tests/browser/browser_dragDrop_after_opening_fxViewTab.js
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+++ b/browser/components/firefoxview/tests/browser/browser_dragDrop_after_opening_fxViewTab.js
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+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests that dragging and dropping tabs into tabbrowser works as intended
+ * after opening the Firefox View tab for RTL builds. There was an issue where
+ * tabs from dragged links were not dropped in the correct tab indexes
+ * for RTL builds because logic for RTL builds did not take into consideration
+ * hidden tabs like the Firefox View tab. This test makes sure that this behavior does not reoccur.
+ */
+add_task(async function () {
+  info("Setting browser to RTL locale");
+  await SpecialPowers.pushPrefEnv({ set: [["intl.l10n.pseudo", "bidi"]] });
+
+  // window.RTL_UI doesn't update in existing windows when this pref is changed,
+  // so we need to test in a new window.
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+
+  const TEST_ROOT = getRootDirectory(gTestPath).replace(
+    "chrome://mochitests/content",
+    "https://example.com"
+  );
+  let newTab = win.gBrowser.tabs[0];
+
+  let waitForTestTabPromise = BrowserTestUtils.waitForNewTab(
+    win.gBrowser,
+    TEST_ROOT + "file_new_tab_page.html"
+  );
+  let testTab = await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    TEST_ROOT + "file_new_tab_page.html"
+  );
+  await waitForTestTabPromise;
+
+  let linkSrcEl = win.document.querySelector("a");
+  ok(linkSrcEl, "Link exists");
+
+  let dropPromise = BrowserTestUtils.waitForEvent(
+    win.gBrowser.tabContainer,
+    "drop"
+  );
+
+  /**
+   * There should be 2 tabs:
+   * 1. new tab (auto-generated)
+   * 2. test tab
+   */
+  is(win.gBrowser.visibleTabs.length, 2, "There should be 2 tabs");
+
+  // Now open Firefox View tab
+  info("Opening Firefox View tab");
+  await openFirefoxViewTab(win);
+
+  /**
+   * There should be 2 visible tabs:
+   * 1. new tab (auto-generated)
+   * 2. test tab
+   * Firefox View tab is hidden.
+   */
+  is(
+    win.gBrowser.visibleTabs.length,
+    2,
+    "There should still be 2 visible tabs after opening Firefox View tab"
+  );
+
+  info("Switching to test tab");
+  await BrowserTestUtils.switchTab(win.gBrowser, testTab);
+
+  let waitForDraggedTabPromise = BrowserTestUtils.waitForNewTab(
+    win.gBrowser,
+    "https://example.com/#test"
+  );
+
+  info("Dragging link between test tab and new tab");
+  EventUtils.synthesizeDrop(
+    linkSrcEl,
+    testTab,
+    [[{ type: "text/plain", data: "https://example.com/#test" }]],
+    "link",
+    win,
+    win,
+    {
+      clientX: testTab.getBoundingClientRect().right,
+    }
+  );
+
+  info("Waiting for drop event");
+  await dropPromise;
+  info("Waiting for dragged tab to be created");
+  let draggedTab = await waitForDraggedTabPromise;
+
+  /**
+   * There should be 3 visible tabs:
+   * 1. new tab (auto-generated)
+   * 2. new tab from dragged link
+   * 3. test tab
+   *
+   * In RTL build, it should appear in the following order:
+   * <test tab> <link dragged tab> <new tab> | <FxView tab>
+   */
+  is(win.gBrowser.visibleTabs.length, 3, "There should be 3 tabs");
+  is(
+    win.gBrowser.visibleTabs.indexOf(newTab),
+    0,
+    "New tab should still be rightmost visible tab"
+  );
+  is(
+    win.gBrowser.visibleTabs.indexOf(draggedTab),
+    1,
+    "Dragged link should positioned at new index"
+  );
+  is(
+    win.gBrowser.visibleTabs.indexOf(testTab),
+    2,
+    "Test tab should be to the left of dragged tab"
+  );
+
+  await BrowserTestUtils.closeWindow(win);
+  await SpecialPowers.popPrefEnv();
+});