Index: test/WebRequest.cpp
===================================================================
--- a/test/WebRequest.cpp
+++ b/test/WebRequest.cpp
@@ -17,6 +17,7 @@
 
 #include <sstream>
 #include "BaseJsTest.h"
+#include "JsLatch.h"
 
 namespace
 {
@@ -25,8 +26,6 @@
   public:
     AdblockPlus::ServerResponse GET(const std::string& url, const AdblockPlus::HeaderList& requestHeaders) const
     {
-      std::this_thread::sleep_for(std::chrono::milliseconds(50));
-
       AdblockPlus::ServerResponse result;
       result.status = NS_OK;
       result.responseStatus = 123;
@@ -64,9 +63,9 @@
 
 TEST_F(MockWebRequestTest, SuccessfulRequest)
 {
-  jsEngine->Evaluate("_webRequest.GET('http://example.com/', {X: 'Y'}, function(result) {foo = result;} )");
-  ASSERT_TRUE(jsEngine->Evaluate("this.foo")->IsUndefined());
-  std::this_thread::sleep_for(std::chrono::milliseconds(200));
+  JsTestingLatch latch(engine, "latch");
+  jsEngine->Evaluate("_webRequest.GET('http://example.com/', {X: 'Y'}, function(result) {foo = result; latch.Arrive();} )");
+  latch.Wait();
   ASSERT_EQ(AdblockPlus::WebRequest::NS_OK, jsEngine->Evaluate("foo.status")->AsInt());
   ASSERT_EQ(123, jsEngine->Evaluate("foo.responseStatus")->AsInt());
   ASSERT_EQ("http://example.com/\nX\nY", jsEngine->Evaluate("foo.responseText")->AsString());
@@ -78,11 +77,9 @@
 {
   // This URL should redirect to easylist-downloads.adblockplus.org and we
   // should get the actual filter list back.
-  jsEngine->Evaluate("_webRequest.GET('https://easylist-downloads.adblockplus.org/easylist.txt', {}, function(result) {foo = result;} )");
-  do
-  {
-    std::this_thread::sleep_for(std::chrono::milliseconds(200));
-  } while (jsEngine->Evaluate("this.foo")->IsUndefined());
+  JsTestingLatch latch(engine, "latch");
+  jsEngine->Evaluate("_webRequest.GET('https://easylist-downloads.adblockplus.org/easylist.txt', {}, function(result) {foo = result; latch.Arrive();} )");
+  latch.Wait();
   ASSERT_EQ("text/plain", jsEngine->Evaluate("foo.responseHeaders['content-type'].substr(0, 10)")->AsString());
   ASSERT_EQ(AdblockPlus::WebRequest::NS_OK, jsEngine->Evaluate("foo.status")->AsInt());
   ASSERT_EQ(200, jsEngine->Evaluate("foo.responseStatus")->AsInt());
@@ -94,7 +91,7 @@
 TEST_F(DefaultWebRequestTest, XMLHttpRequest)
 {
   AdblockPlus::FilterEngine filterEngine(jsEngine);
-
+  JsTestingLatch latch(engine, "latch");
   jsEngine->Evaluate("\
     var result;\
     var request = new XMLHttpRequest();\
@@ -102,13 +99,10 @@
     request.setRequestHeader('X', 'Y');\
     request.setRequestHeader('X2', 'Y2');\
     request.overrideMimeType('text/plain');\
-    request.addEventListener('load', function() {result = request.responseText;}, false);\
-    request.addEventListener('error', function() {result = 'error';}, false);\
+    request.addEventListener('load', function() {result = request.responseText; latch.Arrive();}, false);\
+    request.addEventListener('error', function() {result = 'error'; latch.Arrive();}, false);\
     request.send(null);");
-  do
-  {
-    std::this_thread::sleep_for(std::chrono::milliseconds(200));
-  } while (jsEngine->Evaluate("result")->IsUndefined());
+  latch.Wait();
   ASSERT_EQ(AdblockPlus::WebRequest::NS_OK, jsEngine->Evaluate("request.channel.status")->AsInt());
   ASSERT_EQ(200, jsEngine->Evaluate("request.status")->AsInt());
   ASSERT_EQ("[Adblock Plus ", jsEngine->Evaluate("result.substr(0, 14)")->AsString());