1 files changed, 125 insertions, 0 deletions
diff --git a/browser/components/sessionstore/test/browser_restore_reversed_z_order.js b/browser/components/sessionstore/test/browser_restore_reversed_z_order.js
new file mode 100644
index 0000000000..33d96fd8da
--- /dev/null
+++ b/browser/components/sessionstore/test/browser_restore_reversed_z_order.js
@@ -0,0 +1,125 @@
+"use strict";
+
+const PRIMARY_WINDOW = window;
+
+let gTestURLsMap = new Map([
+  ["about:about", null],
+  ["about:license", null],
+  ["about:robots", null],
+  ["about:mozilla", null],
+]);
+let gBrowserState;
+
+add_setup(async function () {
+  let windows = [];
+  let count = 0;
+  for (let url of gTestURLsMap.keys()) {
+    let window = !count
+      ? PRIMARY_WINDOW
+      : await BrowserTestUtils.openNewBrowserWindow();
+    let browserLoaded = BrowserTestUtils.browserLoaded(
+      window.gBrowser.selectedBrowser
+    );
+    BrowserTestUtils.loadURIString(window.gBrowser.selectedBrowser, url);
+    await browserLoaded;
+    // Capture the title.
+    gTestURLsMap.set(url, window.gBrowser.selectedTab.label);
+    // Minimize the before-last window, to have a different window feature added
+    // to the test.
+    if (count == gTestURLsMap.size - 1) {
+      let activated = BrowserTestUtils.waitForEvent(
+        windows[count - 1],
+        "activate"
+      );
+      window.minimize();
+      await activated;
+    }
+    windows.push(window);
+    ++count;
+  }
+
+  // Wait until we get the lastest history from all windows.
+  await Promise.all(windows.map(window => TabStateFlusher.flushWindow(window)));
+
+  gBrowserState = ss.getBrowserState();
+
+  await promiseAllButPrimaryWindowClosed();
+});
+
+add_task(async function test_z_indices_are_saved_correctly() {
+  let state = JSON.parse(gBrowserState);
+  Assert.equal(
+    state.windows.length,
+    gTestURLsMap.size,
+    "Correct number of windows saved"
+  );
+
+  // Check if we saved state in correct order of creation.
+  let idx = 0;
+  for (let url of gTestURLsMap.keys()) {
+    Assert.equal(
+      state.windows[idx].tabs[0].entries[0].url,
+      url,
+      `Window #${idx} is stored in correct creation order`
+    );
+    ++idx;
+  }
+
+  // Check if we saved a valid zIndex (no null, no undefined or no 0).
+  for (let window of state.windows) {
+    Assert.ok(window.zIndex, "A valid zIndex is stored");
+  }
+
+  Assert.equal(
+    state.windows[0].zIndex,
+    3,
+    "Window #1 should have the correct z-index"
+  );
+  Assert.equal(
+    state.windows[1].zIndex,
+    2,
+    "Window #2 should have correct z-index"
+  );
+  Assert.equal(
+    state.windows[2].zIndex,
+    1,
+    "Window #3 should be the topmost window"
+  );
+  Assert.equal(
+    state.windows[3].zIndex,
+    4,
+    "Minimized window should be the last window to restore"
+  );
+});
+
+add_task(async function test_windows_are_restored_in_reversed_z_order() {
+  await promiseBrowserState(gBrowserState);
+
+  let indexedTabLabels = [...gTestURLsMap.values()];
+  let tabsRestoredLabels = BrowserWindowTracker.orderedWindows.map(
+    window => window.gBrowser.selectedTab.label
+  );
+
+  Assert.equal(
+    tabsRestoredLabels[0],
+    indexedTabLabels[2],
+    "First restored tab should be last used tab"
+  );
+  Assert.equal(
+    tabsRestoredLabels[1],
+    indexedTabLabels[1],
+    "Second restored tab is correct"
+  );
+  Assert.equal(
+    tabsRestoredLabels[2],
+    indexedTabLabels[0],
+    "Third restored tab is correct"
+  );
+  Assert.equal(
+    tabsRestoredLabels[3],
+    indexedTabLabels[3],
+    "Last restored tab should be a minimized window"
+  );
+
+  await promiseAllButPrimaryWindowClosed();
+});