Issue 4202 - Fix failing AndroidWebRequestTest.testXMLHttpRequest

libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/AndroidWebRequestTest.java

Index: libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/AndroidWebRequestTest.java
===================================================================
--- a/libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/AndroidWebRequestTest.java
+++ b/libadblockplus-android-tests/src/org/adblockplus/libadblockplus/tests/AndroidWebRequestTest.java
@@ -13,16 +13,17 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 package org.adblockplus.libadblockplus.tests;
 
 import org.adblockplus.android.AndroidWebRequest;
+import org.adblockplus.libadblockplus.FilterEngine;
 import org.adblockplus.libadblockplus.JsValue;
 import org.adblockplus.libadblockplus.ServerResponse;
 
 import org.junit.Test;
 
 public class AndroidWebRequestTest extends BaseJsTest
 {
     @Override
@@ -63,23 +64,27 @@
             jsEngine.evaluate("foo.responseText.substr(0, 14)").asString());
         JsValue jsHeaders = jsEngine.evaluate("foo.responseHeaders");
         assertNotNull(jsHeaders);
         assertFalse(jsHeaders.isUndefined());
         assertFalse(jsHeaders.isNull());
         assertTrue(jsHeaders.isObject());
         assertEquals(
             "text/plain",
-            jsEngine.evaluate("foo.responseHeaders['Content-Type'].substr(0,10)").asString());
+            jsEngine.evaluate("foo.responseHeaders['content-type'].substr(0,10)").asString());
         assertTrue(jsEngine.evaluate("foo.responseHeaders['location']").isUndefined());
     }
 
     @Test
     public void testXMLHttpRequest()
     {
+        // creating not used anywhere FilterEngine object is not as useless as it seems:
+        // it loads compat.js JsEngine to add XMLHttpRequest class support
+        new FilterEngine(jsEngine);
+
         jsEngine.evaluate(
             "var result;\n" +
             "var request = new XMLHttpRequest();\n" +
             "request.open('GET', 'https://easylist-downloads.adblockplus.org/easylist.txt');\n" +
             "request.setRequestHeader('X', 'Y');\n" +
             "request.setRequestHeader('X2', 'Y2');\n" +
             "request.overrideMimeType('text/plain');\n" +
             "request.addEventListener('load',function() {result=request.responseText;}, false);\n" +