Bug 1706608 - Part 4: Modify the gTest TestURLQueryStringStripper. r=dimi

Because the URLQueryStringStripper will no longer access the pref
directly. We need to use the gTest and make it to wait the pref change
been set to the stripper to do the test properly.

Differential Revision: https://phabricator.services.mozilla.com/D116849

toolkit/components/antitracking/test/gtest/TestURLQueryStringStripper.cpp

@@ -10,6 +10,7 @@
 #include "nsStringFwd.h"
 
 #include "mozilla/Preferences.h"
+#include "mozilla/SpinEventLoopUntil.h"
 #include "mozilla/URLQueryStringStripper.h"
 
 using namespace mozilla;
@@ -38,10 +39,45 @@ void DoTest(const nsACString& aTestURL, const nsACString& aExpectedURL,
   }
 }
 
+class StripListObserver final : public nsIURLQueryStrippingListObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIURLQUERYSTRIPPINGLISTOBSERVER
+
+  bool IsStillWaiting() { return mWaitingObserver; }
+  void StartWaitingObserver() { mWaitingObserver = true; }
+
+  StripListObserver() : mWaitingObserver(false) {
+    mService = do_GetService("@mozilla.org/query-stripping-list-service;1");
+    mService->RegisterAndRunObserver(this);
+  }
+
+ private:
+  ~StripListObserver() {
+    mService->UnregisterObserver(this);
+    mService = nullptr;
+  }
+
+  bool mWaitingObserver;
+  nsCOMPtr<nsIURLQueryStrippingListService> mService;
+};
+
+NS_IMPL_ISUPPORTS(StripListObserver, nsIURLQueryStrippingListObserver)
+
+NS_IMETHODIMP
+StripListObserver::OnQueryStrippingListUpdate(const nsAString& aStripList,
+                                              const nsACString& aAllowList) {
+  mWaitingObserver = false;
+  return NS_OK;
+}
+
 TEST(TestURLQueryStringStripper, TestPrefDisabled)
 {
   // Disable the query string stripping by the pref and make sure the stripping
   // is disabled.
+  // Note that we don't need to run a dummy test to create the
+  // URLQueryStringStripper here because the stripper will never be created if
+  // the query stripping is disabled.
   Preferences::SetCString(kPrefQueryStrippingList, "fooBar foobaz");
   Preferences::SetBool(kPrefQueryStrippingEnabled, false);
 
@@ -53,9 +89,21 @@ TEST(TestURLQueryStringStripper, TestPrefDisabled)
 TEST(TestURLQueryStringStripper, TestEmptyStripList)
 {
   // Make sure there is no error if the strip list is empty.
-  Preferences::SetCString(kPrefQueryStrippingList, "");
   Preferences::SetBool(kPrefQueryStrippingEnabled, true);
 
+  // To create the URLQueryStringStripper, we need to run a dummy test after
+  // the query stripping is enabled. By doing this, the stripper will be
+  // initiated and we are good to test.
+  DoTest("https://example.com/"_ns, ""_ns, false);
+
+  // Set the strip list to empty and wait until the pref setting is set to the
+  // stripper.
+  RefPtr<StripListObserver> observer = new StripListObserver();
+  observer->StartWaitingObserver();
+  Preferences::SetCString(kPrefQueryStrippingList, "");
+  MOZ_ALWAYS_TRUE(mozilla::SpinEventLoopUntil(
+      [&]() -> bool { return !observer->IsStillWaiting(); }));
+
   DoTest("https://example.com/"_ns, ""_ns, false);
   DoTest("https://example.com/?Barfoo=123"_ns, ""_ns, false);
   DoTest("https://example.com/?fooBar=123&foobaz"_ns, ""_ns, false);
@@ -63,9 +111,19 @@ TEST(TestURLQueryStringStripper, TestEmptyStripList)
 
 TEST(TestURLQueryStringStripper, TestStripping)
 {
-  Preferences::SetCString(kPrefQueryStrippingList, "fooBar foobaz");
   Preferences::SetBool(kPrefQueryStrippingEnabled, true);
 
+  // A dummy test to initiate the URLQueryStringStripper.
+  DoTest("https://example.com/"_ns, ""_ns, false);
+
+  // Set the pref and create an observer to wait the pref setting is set to the
+  // stripper.
+  RefPtr<StripListObserver> observer = new StripListObserver();
+  observer->StartWaitingObserver();
+  Preferences::SetCString(kPrefQueryStrippingList, "fooBar foobaz");
+  MOZ_ALWAYS_TRUE(mozilla::SpinEventLoopUntil(
+      [&]() -> bool { return !observer->IsStillWaiting(); }));
+
   // Test the stripping.
   DoTest("https://example.com/"_ns, ""_ns, false);
   DoTest("https://example.com/?Barfoo=123"_ns, ""_ns, false);
@@ -85,7 +143,10 @@ TEST(TestURLQueryStringStripper, TestStripping)
          "https://example.com/?AfoobazB=123"_ns, false);
 
   // Change the strip list pref to see if it is updated properly.
+  observer->StartWaitingObserver();
   Preferences::SetCString(kPrefQueryStrippingList, "Barfoo bazfoo");
+  MOZ_ALWAYS_TRUE(mozilla::SpinEventLoopUntil(
+      [&]() -> bool { return !observer->IsStillWaiting(); }));
 
   DoTest("https://example.com/?fooBar=123"_ns, ""_ns, false);
   DoTest("https://example.com/?fooBar=123&foobaz"_ns, ""_ns, false);