1 files changed, 67 insertions, 0 deletions
diff --git a/toolkit/components/reader/test/browser_readerMode_colorSchemePref.js b/toolkit/components/reader/test/browser_readerMode_colorSchemePref.js
new file mode 100644
index 0000000000..0bee6eaf05
--- /dev/null
+++ b/toolkit/components/reader/test/browser_readerMode_colorSchemePref.js
@@ -0,0 +1,67 @@
+/* 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/. */
+
+"use strict";
+
+const TEST_PATH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://example.com"
+);
+
+async function testColorScheme(aPref, aExpectation) {
+  // Set the browser content theme to light or dark.
+  Services.prefs.setIntPref("browser.theme.content-theme", aPref);
+
+  // Reader Mode Color Scheme Preference must be manually set by the user, will
+  // default to "auto" initially.
+  Services.prefs.setCharPref("reader.color_scheme", aExpectation);
+
+  let aBodyExpectation = aExpectation;
+  if (aBodyExpectation === "auto") {
+    aBodyExpectation = aPref === 1 ? "light" : "dark";
+  }
+
+  // Open a browser tab, enter reader mode, and test if we have the valid
+  // reader mode color scheme preference pre-selected.
+  await BrowserTestUtils.withNewTab(
+    TEST_PATH + "readerModeArticle.html",
+    async function (browser) {
+      let pageShownPromise = BrowserTestUtils.waitForContentEvent(
+        browser,
+        "AboutReaderContentReady"
+      );
+
+      let readerButton = document.getElementById("reader-mode-button");
+      readerButton.click();
+      await pageShownPromise;
+
+      let colorScheme = Services.prefs.getCharPref("reader.color_scheme");
+
+      Assert.equal(colorScheme, aExpectation);
+
+      await SpecialPowers.spawn(browser, [aBodyExpectation], expectation => {
+        let bodyClass = content.document.body.className;
+        ok(
+          bodyClass.includes(expectation),
+          "The body of the test document has the correct color scheme."
+        );
+      });
+    }
+  );
+}
+
+/**
+ * Test that opening reader mode maintains the correct color scheme preference
+ * until the user manually sets a different color scheme.
+ */
+add_task(async function () {
+  await testColorScheme(0, "auto");
+  await testColorScheme(1, "auto");
+  await testColorScheme(0, "light");
+  await testColorScheme(1, "light");
+  await testColorScheme(0, "dark");
+  await testColorScheme(1, "dark");
+  await testColorScheme(0, "sepia");
+  await testColorScheme(1, "sepia");
+});