Add new UrlPatternIndex test.

components/subresource_filter/core/common/url_pattern_index_unittest.cc

Index: components/subresource_filter/core/common/url_pattern_index_unittest.cc
diff --git a/components/subresource_filter/core/common/url_pattern_index_unittest.cc b/components/subresource_filter/core/common/url_pattern_index_unittest.cc
index 3fe3788b3c5169950f1179c51d0a547e8f2d11b7..b7c2c6eac43baf2e361e23ba4b154100862ed10b 100644
--- a/components/subresource_filter/core/common/url_pattern_index_unittest.cc
+++ b/components/subresource_filter/core/common/url_pattern_index_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "components/subresource_filter/core/common/url_pattern_index.h"
 
+#include <algorithm>
 #include <memory>
 #include <string>
 #include <vector>
@@ -52,6 +53,14 @@ class UrlPatternIndexTest : public ::testing::Test {
         IsThirdParty(url, document_origin), disable_generic_rules);
   }
 
+  bool IsOutOfRange(const flat::UrlRule* rule) const {
+    if (!rule)
+      return false;
+    const auto* data = reinterpret_cast<const uint8_t*>(rule);
+    return data < flat_builder_->GetBufferPointer() ||
+           data >= flat_builder_->GetBufferPointer() + flat_builder_->GetSize();
+  }
+
   void Reset() {
     index_matcher_.reset();
     index_builder_.reset();
@@ -663,4 +672,34 @@ TEST_F(UrlPatternIndexTest, RulesWithSupportedAndUnsupportedTypes) {
       FindMatch("http://example.com", nullptr, kNoElement, kGenericBlock));
 }
 
+TEST_F(UrlPatternIndexTest, FindMatchReturnsCorrectRules) {
+  constexpr size_t kNumOfPatterns = 1024;
+
+  std::vector<std::string> url_patterns(kNumOfPatterns);
+  for (size_t i = 0; i < kNumOfPatterns; ++i) {
+    url_patterns[i] = "http://example." + std::to_string(i) + ".com";
+    ASSERT_TRUE(
+        AddUrlRule(MakeUrlRule(UrlPattern(url_patterns[i], kSubstring))))
+        << "Rule #" << i;
+  }
+  Finish();
+
+  std::reverse(url_patterns.begin() + kNumOfPatterns / 2, url_patterns.end());
+  for (const std::string& url_pattern : url_patterns) {
+    SCOPED_TRACE(::testing::Message() << "UrlPattern: " << url_pattern);
+
+    const flat::UrlRule* rule = FindMatch(url_pattern);
+    ASSERT_TRUE(rule);
+    ASSERT_FALSE(IsOutOfRange(rule));
+
+    const flatbuffers::String* rule_pattern = rule->url_pattern();
+    ASSERT_TRUE(rule_pattern);
+    EXPECT_EQ(url_pattern,
+              base::StringPiece(rule_pattern->data(), rule_pattern->size()));
+  }
+
+  EXPECT_FALSE(
+      FindMatch("http://example." + std::to_string(kNumOfPatterns) + ".com"));
+}
+
 }  // namespace subresource_filter