1 files changed, 87 insertions, 0 deletions
diff --git a/browser/components/shell/test/browser_setDesktopBackgroundPreview.js b/browser/components/shell/test/browser_setDesktopBackgroundPreview.js
new file mode 100644
index 0000000000..b2dbe13db8
--- /dev/null
+++ b/browser/components/shell/test/browser_setDesktopBackgroundPreview.js
@@ -0,0 +1,87 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Check whether the preview image for setDesktopBackground is rendered
+ * correctly, without stretching
+ */
+
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "about:logo",
+    },
+    async browser => {
+      const dialogLoad = BrowserTestUtils.domWindowOpened(null, async win => {
+        await BrowserTestUtils.waitForEvent(win, "load");
+        Assert.equal(
+          win.document.documentElement.getAttribute("windowtype"),
+          "Shell:SetDesktopBackground",
+          "Opened correct window"
+        );
+        return true;
+      });
+
+      const image = content.document.images[0];
+      EventUtils.synthesizeMouseAtCenter(image, { type: "contextmenu" });
+
+      const menu = document.getElementById("contentAreaContextMenu");
+      await BrowserTestUtils.waitForPopupEvent(menu, "shown");
+      const menuClosed = BrowserTestUtils.waitForPopupEvent(menu, "hidden");
+
+      const menuItem = document.getElementById("context-setDesktopBackground");
+      try {
+        menu.activateItem(menuItem);
+      } catch (ex) {
+        ok(
+          menuItem.hidden,
+          "should only fail to activate when menu item is hidden"
+        );
+        ok(
+          !ShellService.canSetDesktopBackground,
+          "Should only hide when not able to set the desktop background"
+        );
+        is(
+          AppConstants.platform,
+          "linux",
+          "Should always be able to set desktop background on non-linux platforms"
+        );
+        todo(false, "Skipping test on this configuration");
+
+        menu.hidePopup();
+        await menuClosed;
+        return;
+      }
+
+      await menuClosed;
+
+      const win = await dialogLoad;
+
+      /* setDesktopBackground.js does a setTimeout to wait for correct
+       dimensions. If we don't wait here we could read the preview dimensions
+       before they're changed to match the screen */
+      await TestUtils.waitForTick();
+
+      const canvas = win.document.getElementById("screen");
+      const screenRatio = screen.width / screen.height;
+      const previewRatio = canvas.clientWidth / canvas.clientHeight;
+
+      info(`Screen dimensions are ${screen.width}x${screen.height}`);
+      info(`Screen's raw ratio is ${screenRatio}`);
+      info(
+        `Preview dimensions are ${canvas.clientWidth}x${canvas.clientHeight}`
+      );
+      info(`Preview's raw ratio is ${previewRatio}`);
+
+      Assert.ok(
+        previewRatio < screenRatio + 0.01 && previewRatio > screenRatio - 0.01,
+        "Preview's aspect ratio is within ±.01 of screen's"
+      );
+
+      win.close();
+
+      await menuClosed;
+    }
+  );
+});