1 files changed, 56 insertions, 0 deletions
diff --git a/toolkit/components/reader/test/browser_readerMode_hidden_nodes.js b/toolkit/components/reader/test/browser_readerMode_hidden_nodes.js
new file mode 100644
index 0000000000..38a5955f61
--- /dev/null
+++ b/toolkit/components/reader/test/browser_readerMode_hidden_nodes.js
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test that the reader mode button appears and works properly on
+ * reader-able content.
+ */
+const TEST_PREFS = [["reader.parse-on-load.enabled", true]];
+
+const TEST_PATH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://example.com"
+);
+
+var readerButton = document.getElementById("reader-mode-button");
+
+add_task(async function test_reader_button() {
+  registerCleanupFunction(function () {
+    // Reset test prefs.
+    TEST_PREFS.forEach(([name, value]) => {
+      Services.prefs.clearUserPref(name);
+    });
+    while (gBrowser.tabs.length > 1) {
+      gBrowser.removeCurrentTab();
+    }
+  });
+
+  // Set required test prefs.
+  TEST_PREFS.forEach(([name, value]) => {
+    Services.prefs.setBoolPref(name, value);
+  });
+
+  let tab = (gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser));
+  is_element_hidden(
+    readerButton,
+    "Reader mode button is not present on a new tab"
+  );
+  // Point tab to a test page that is not reader-able due to hidden nodes.
+  let url = TEST_PATH + "readerModeArticleHiddenNodes.html";
+  let paintPromise = BrowserTestUtils.waitForContentEvent(
+    tab.linkedBrowser,
+    "MozAfterPaint",
+    false,
+    e =>
+      e.originalTarget.location.href.endsWith("HiddenNodes.html") &&
+      e.originalTarget.document.readyState == "complete"
+  );
+  BrowserTestUtils.loadURIString(tab.linkedBrowser, url);
+  await paintPromise;
+
+  is_element_hidden(
+    readerButton,
+    "Reader mode button is still not present on tab with unreadable content."
+  );
+});