Unit test for NULL values in preference validation delegate.

chrome/browser/safe_browsing/preference_validation_delegate_unittest.cc

Index: chrome/browser/safe_browsing/preference_validation_delegate_unittest.cc
diff --git a/chrome/browser/safe_browsing/preference_validation_delegate_unittest.cc b/chrome/browser/safe_browsing/preference_validation_delegate_unittest.cc
index 0e66dc00ed80e9e9806b607197dcf4a5344ea45b..e4d32ef71d50d5ae04ca9672712603658f9cb148 100644
--- a/chrome/browser/safe_browsing/preference_validation_delegate_unittest.cc
+++ b/chrome/browser/safe_browsing/preference_validation_delegate_unittest.cc
@@ -83,6 +83,17 @@ class PreferenceValidationDelegateTest : public testing::Test {
   scoped_ptr<TrackedPreferenceValidationDelegate> instance_;
 };
 
+// Tests that a NULL value results in an incident with no value.
+TEST_F(PreferenceValidationDelegateTest, NullValue) {
+  instance_->OnAtomicPreferenceValidation(kPrefPath_,
+                                          NULL,
+                                          PrefHashStoreTransaction::CLEARED,
+                                          TrackedPreferenceHelper::DONT_RESET);
+  safe_browsing::ClientIncidentReport_IncidentData* incident =
+      incidents_.back();
+  EXPECT_FALSE(incident->tracked_preference().has_atomic_value());

[gab, 2014/06/16 22:33:27]

Optional: instead of returning no serialized value, you may want to return a
special string which you'll know means it was NULL server-side.

This may help in case you somehow start getting reports where the value is
somehow missing; you'd then be able to differentiate NULL values from broken
uploads.

[grt (UTC plus 2), 2014/06/17 02:05:33]

value_state() indicates that it was cleared. i've added this to the test.

+}
+
 // Tests that all supported value types can be stringified into an incident. The
 // parameters for the test are the type of value to test and the expected value
 // string.