1 files changed, 174 insertions, 0 deletions
diff --git a/browser/base/content/test/about/browser_aboutNetError_native_fallback.js b/browser/base/content/test/about/browser_aboutNetError_native_fallback.js
new file mode 100644
index 0000000000..4a87ad5cce
--- /dev/null
+++ b/browser/base/content/test/about/browser_aboutNetError_native_fallback.js
@@ -0,0 +1,174 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+let oldProxyType = Services.prefs.getIntPref("network.proxy.type");
+
+function reset() {
+  Services.prefs.clearUserPref("network.trr.display_fallback_warning");
+  Services.prefs.clearUserPref("network.trr.mode");
+  Services.prefs.clearUserPref("network.dns.native-is-localhost");
+  Services.prefs.clearUserPref("doh-rollout.disable-heuristics");
+  Services.prefs.setIntPref("network.proxy.type", oldProxyType);
+  Services.prefs.clearUserPref("network.trr.uri");
+
+  Services.dns.setHeuristicDetectionResult(Ci.nsITRRSkipReason.TRR_OK);
+}
+
+// This helper verifies that the given url loads correctly
+async function verifyLoad(url, testName) {
+  let browser;
+  await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    () => {
+      gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser, url);
+      browser = gBrowser.selectedBrowser;
+    },
+    true
+  );
+
+  await SpecialPowers.spawn(browser, [{ url, testName }], function (args) {
+    const doc = content.document;
+    ok(
+      doc.documentURI == args.url,
+      "Should have loaded page: " + args.testName
+    );
+  });
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+}
+
+// This helper verifies that loading the given url will lead to an error -- the fallback warning if the parameter is true
+async function verifyError(url, fallbackWarning, testName) {
+  // Clear everything.
+  Services.telemetry.clearEvents();
+  await TestUtils.waitForCondition(() => {
+    let events = Services.telemetry.snapshotEvents(
+      Ci.nsITelemetry.DATASET_PRERELEASE_CHANNELS,
+      true
+    ).content;
+    return !events || !events.length;
+  });
+  Services.telemetry.setEventRecordingEnabled("security.doh.neterror", true);
+
+  let browser;
+  let pageLoaded;
+  await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    () => {
+      gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser, url);
+      browser = gBrowser.selectedBrowser;
+      pageLoaded = BrowserTestUtils.waitForErrorPage(browser);
+    },
+    false
+  );
+
+  info("Loading and waiting for the net error");
+  await pageLoaded;
+
+  await SpecialPowers.spawn(
+    browser,
+    [{ url, fallbackWarning, testName }],
+    function (args) {
+      const doc = content.document;
+
+      ok(doc.documentURI.startsWith("about:neterror"));
+      "Should be showing error page: " + args.testName;
+
+      const titleEl = doc.querySelector(".title-text");
+      const actualDataL10nID = titleEl.getAttribute("data-l10n-id");
+      if (args.fallbackWarning) {
+        is(
+          actualDataL10nID,
+          "dns-not-found-native-fallback-title2",
+          "Correct fallback warning error page title is set: " + args.testName
+        );
+      } else {
+        ok(
+          actualDataL10nID != "dns-not-found-native-fallback-title2",
+          "Should not show fallback warning: " + args.testName
+        );
+      }
+    }
+  );
+
+  if (fallbackWarning) {
+    let loadEvent = await TestUtils.waitForCondition(() => {
+      let events = Services.telemetry.snapshotEvents(
+        Ci.nsITelemetry.DATASET_PRERELEASE_CHANNELS,
+        true
+      ).content;
+      return events?.find(
+        e => e[1] == "security.doh.neterror" && e[2] == "load"
+      );
+    }, "recorded telemetry for the load");
+    loadEvent.shift();
+    Assert.deepEqual(loadEvent, [
+      "security.doh.neterror",
+      "load",
+      "dohwarning",
+      "NativeFallbackWarning",
+      {
+        mode: "0",
+        provider_key: "0.0.0.0",
+        skip_reason: "TRR_HEURISTIC_TRIPPED_CANARY",
+      },
+    ]);
+  }
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+}
+
+// This test verifies that the native fallback warning appears in the desired scenarios, and only in those scenarios
+add_task(async function nativeFallbackWarnings() {
+  Services.prefs.setBoolPref("network.dns.native-is-localhost", true);
+
+  // Disable heuristics since they will attempt to connect to external servers
+  Services.prefs.setBoolPref("doh-rollout.disable-heuristics", true);
+
+  // Set a local TRR to prevent external connections
+  Services.prefs.setCharPref("network.trr.uri", "https://0.0.0.0/dns-query");
+
+  registerCleanupFunction(reset);
+
+  // Test without DoH
+  Services.prefs.setIntPref(
+    "network.trr.mode",
+    Ci.nsIDNSService.MODE_NATIVEONLY
+  );
+
+  Services.dns.clearCache(true);
+  await verifyLoad("https://www.example.com/", "valid url, no error");
+
+  // Should not trigger the native fallback warning
+  await verifyError("https://does-not-exist.test", false, "non existent url");
+
+  // We need to disable proxy, otherwise TRR isn't used for name resolution.
+  Services.prefs.setIntPref("network.proxy.type", 0);
+
+  // Switch to TRR first
+  Services.prefs.setIntPref(
+    "network.trr.mode",
+    Ci.nsIDNSService.MODE_NATIVEONLY
+  );
+  Services.prefs.setBoolPref("network.trr.display_fallback_warning", true);
+
+  // Simulate a tripped canary network
+  Services.dns.setHeuristicDetectionResult(
+    Ci.nsITRRSkipReason.TRR_HEURISTIC_TRIPPED_CANARY
+  );
+
+  // We should see the fallback warning displayed in both of these scenarios
+  Services.dns.clearCache(true);
+  await verifyError(
+    "https://www.example.com",
+    true,
+    "canary heuristic tripped"
+  );
+  await verifyError(
+    "https://does-not-exist.test",
+    true,
+    "canary heuristic tripped - non existent url"
+  );
+
+  reset();
+});