diff -r 000000000000 -r 6474c204b198 extensions/universalchardet/tests/CharsetDetectionTests.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/extensions/universalchardet/tests/CharsetDetectionTests.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 et sw=4 tw=80: */
+var gExpectedCharset;
+var gOldPref;
+var gDetectorList;
+var gTestIndex;
+var gLocalDir;
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+function CharsetDetectionTests(aTestFile, aExpectedCharset, aDetectorList)
+{
+    gExpectedCharset = aExpectedCharset;
+    gDetectorList = aDetectorList;
+
+    InitDetectorTests();
+
+    var fileURI = gLocalDir + aTestFile;
+    $("testframe").src = fileURI;
+
+    SimpleTest.waitForExplicitFinish();
+}
+
+function InitDetectorTests()
+{
+    var prefService = Cc["@mozilla.org/preferences-service;1"]
+        .getService(Ci.nsIPrefBranch);
+    var str = Cc["@mozilla.org/supports-string;1"]
+        .createInstance(Ci.nsISupportsString);
+    var loader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
+        .getService(Ci.mozIJSSubScriptLoader);
+    var ioService = Cc['@mozilla.org/network/io-service;1']
+        .getService(Ci.nsIIOService);
+    loader.loadSubScript("chrome://mochikit/content/chrome-harness.js");
+
+    try {
+        gOldPref = prefService
+            .getComplexValue("intl.charset.detector",
+                             Ci.nsIPrefLocalizedString).data;
+    } catch (e) {
+        gOldPref = "";
+    }
+    SetDetectorPref(gDetectorList[0]);
+    gTestIndex = 0;
+    $("testframe").onload = DoDetectionTest;
+
+    if (gExpectedCharset == "default") {
+        // No point trying to be generic here, because we have plenty of other
+        // unit tests that fail if run using a non-windows-1252 locale.
+        gExpectedCharset = "windows-1252";
+    }
+
+    // Get the local directory. This needs to be a file: URI because chrome:
+    // URIs are always UTF-8 (bug 617339) and we are testing decoding from other
+    // charsets.
+    var jar = getJar(getRootDirectory(window.location.href));
+    var dir = jar ?
+                extractJarToTmp(jar) :
+                getChromeDir(getResolvedURI(window.location.href));
+    gLocalDir = ioService.newFileURI(dir).spec;
+}
+
+function SetDetectorPref(aPrefValue)
+{
+    var prefService = Cc["@mozilla.org/preferences-service;1"]
+                      .getService(Ci.nsIPrefBranch);
+    var str = Cc["@mozilla.org/supports-string;1"]
+              .createInstance(Ci.nsISupportsString);
+    str.data = aPrefValue;
+    prefService.setComplexValue("intl.charset.detector",
+                                Ci.nsISupportsString, str);
+    gCurrentDetector = aPrefValue;
+}
+
+function DoDetectionTest() {
+    var iframeDoc = $("testframe").contentDocument;
+    var charset = iframeDoc.characterSet;
+
+    is(charset, gExpectedCharset,
+       "decoded as " + gExpectedCharset + " by " + gDetectorList[gTestIndex]);
+
+    if (++gTestIndex < gDetectorList.length) {
+        SetDetectorPref(gDetectorList[gTestIndex]);
+        iframeDoc.location.reload();
+    } else {
+        CleanUpDetectionTests();
+    }
+}
+
+function CleanUpDetectionTests() {
+    SetDetectorPref(gOldPref);
+    SimpleTest.finish();
+}
+