Bug 1002724 - Test that HTTPS is tried if typed host name doesn't respond via HTTP. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D75085

docshell/test/browser/browser.ini

@@ -153,3 +153,4 @@ skip-if = !e10s # e10s specific test.
 [browser_tab_replace_while_loading.js]
 skip-if = (os == 'linux' && bits == 64 && os_version == '18.04') # Bug 1604237
 [browser_browsing_context_discarded.js]
+[browser_fall_back_to_https.js]

docshell/test/browser/browser_fall_back_to_https.js

@@ -0,0 +1,66 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/*
+ * This test is for bug 1002724.
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=1002724
+ *
+ * When a user enters a host name or IP address in the URL bar, "http" is
+ * assumed.  If the host rejects connections on port 80, we try HTTPS as a
+ * fall-back and only fail if HTTPS connection fails.
+ *
+ * This tests that when a user enters "example.com", it attempts to load
+ * http://example.com:80 (not rejected), and when trying 127.0.0.2
+ * (which rejects connections on port 80), it fails then loads
+ * https://127.0.0.2:443 instead.
+ */
+
+const { UrlbarTestUtils } = ChromeUtils.import(
+  "resource://testing-common/UrlbarTestUtils.jsm"
+);
+
+const bug1002724_tests = [
+  {
+    original: "example.com",
+    expected: "http://example.com",
+    explanation: "Should load HTTP version of example.com",
+  },
+  {
+    original: "127.0.0.2",
+    expected: "https://127.0.0.2",
+    explanation: "Should reject 127.0.0.2 on HTTP but load the HTTPS version",
+  },
+];
+
+async function test_one(test_obj) {
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:blank"
+  );
+  gURLBar.focus();
+  gURLBar.value = test_obj.original;
+
+  let loadPromise = BrowserTestUtils.browserLoaded(tab.linkedBrowser, false);
+  EventUtils.synthesizeKey("KEY_Enter");
+  await loadPromise;
+
+  ok(
+    tab.linkedBrowser.currentURI.spec.startsWith(test_obj.expected),
+    test_obj.explanation
+  );
+
+  BrowserTestUtils.removeTab(tab);
+}
+
+add_task(async function test_bug1002724() {
+  await SpecialPowers.pushPrefEnv(
+    // Disable HSTS preload just in case.
+    { set: [["network.stricttransportsecurity.preloadlist", false]] }
+  );
+
+  for (let test of bug1002724_tests) {
+    await test_one(test);
+  }
+});