Add fuzzer test for preg_parser

components/policy/core/common/preg_parser_unittest.cc

Index: components/policy/core/common/preg_parser_unittest.cc
diff --git a/components/policy/core/common/preg_parser_unittest.cc b/components/policy/core/common/preg_parser_unittest.cc
index 757ac70e62ef13b65ba266688a3042098cb3651f..2f05fb09914570a47fa1de3528e6bd4adb9d5a70 100644
--- a/components/policy/core/common/preg_parser_unittest.cc
+++ b/components/policy/core/common/preg_parser_unittest.cc
@@ -22,6 +22,10 @@ namespace policy {
 namespace preg_parser {
 namespace {
 
+const char kRegistryPolFile[] = "chrome/test/data/policy/registry.pol";
+const char kRegistryKey[] = "SOFTWARE\\Policies\\Chromium";
+const char kPartialRegistryKey[] = "SOFTWARE\\Policies\\Chro";
+
 // Check whether two RegistryDicts equal each other.
 testing::AssertionResult RegistryDictEquals(const RegistryDict& a,
                                             const RegistryDict& b) {
@@ -30,15 +34,20 @@ testing::AssertionResult RegistryDictEquals(const RegistryDict& a,
   for (; iter_key_a != a.keys().end() && iter_key_b != b.keys().end();
        ++iter_key_a, ++iter_key_b) {
     if (iter_key_a->first != iter_key_b->first) {
-      return testing::AssertionFailure()
-          << "Key mismatch " << iter_key_a->first
-          << " vs. " << iter_key_b->first;
+      return testing::AssertionFailure() << "Key mismatch " << iter_key_a->first
+                                         << " vs. " << iter_key_b->first;
     }
-    testing::AssertionResult result = RegistryDictEquals(*iter_key_a->second,
-                                                         *iter_key_b->second);
+    testing::AssertionResult result =
+        RegistryDictEquals(*iter_key_a->second, *iter_key_b->second);
     if (!result)
       return result;
   }
+  if (iter_key_a != a.keys().end())
+    return testing::AssertionFailure()
+           << "key mismatch, a has extra key " << iter_key_a->first;
+  if (iter_key_b != b.keys().end())
+    return testing::AssertionFailure()
+           << "key mismatch, b has extra key " << iter_key_b->first;
 
   auto iter_value_a = a.values().begin();
   auto iter_value_b = b.values().begin();
@@ -53,19 +62,25 @@ testing::AssertionResult RegistryDictEquals(const RegistryDict& a,
              << "=" << *iter_value_b->second.get();
     }
   }
+  if (iter_value_a != a.values().end())
+    return testing::AssertionFailure()
+           << "Value mismatch, a has extra value " << iter_value_a->first << "="
+           << *iter_value_a->second.get();
+  if (iter_value_b != b.values().end())
+    return testing::AssertionFailure()
+           << "Value mismatch, b has extra value " << iter_value_b->first << "="
+           << *iter_value_b->second.get();
 
   return testing::AssertionSuccess();
 }
 
-void SetInteger(RegistryDict* dict,
-                const std::string& name,
-                int value) {
+void SetInteger(RegistryDict* dict, const std::string& name, int value) {
   dict->SetValue(name, base::WrapUnique<base::Value>(new base::Value(value)));
 }
 
 void SetString(RegistryDict* dict,
                const std::string& name,
-               const std::string&  value) {
+               const std::string& value) {
   dict->SetValue(name, base::WrapUnique<base::Value>(new base::Value(value)));
 }
 
@@ -90,12 +105,10 @@ TEST(PRegParserTest, TestParseFile) {
   dict.SetKey("DelValsTest", std::move(subdict));
 
   // Run the parser.
-  base::FilePath test_file(
-      test_data_dir.AppendASCII("chrome/test/data/policy/registry.pol"));
+  base::FilePath test_file(test_data_dir.AppendASCII(kRegistryPolFile));
   PolicyLoadStatusSample status;
-  ASSERT_TRUE(preg_parser::ReadFile(
-      test_file, base::ASCIIToUTF16("SOFTWARE\\Policies\\Chromium"),
-      &dict, &status));
+  ASSERT_TRUE(preg_parser::ReadFile(test_file, base::ASCIIToUTF16(kRegistryKey),
+                                    &dict, &status));
 
   // Build the expected output dictionary.
   RegistryDict expected;
@@ -116,6 +129,29 @@ TEST(PRegParserTest, TestParseFile) {
   EXPECT_TRUE(RegistryDictEquals(dict, expected));
 }
 
+TEST(PRegParserTest, SubstringRootInvalid) {
+  // A root of "alpha/beta/gamma" should not be considered a valid root for a
+  // key like "alpha/beta/gammadelta".
+  base::FilePath test_data_dir;
+  ASSERT_TRUE(PathService::Get(base::DIR_SOURCE_ROOT, &test_data_dir));
+
+  base::FilePath test_file(test_data_dir.AppendASCII(kRegistryPolFile));
+  RegistryDict empty;
+  PolicyLoadStatusSample status;
+
+  // No data should be loaded for key = kPartialRegistryKey.
+  RegistryDict dict1;
+  ASSERT_TRUE(preg_parser::ReadFile(
+      test_file, base::ASCIIToUTF16(kPartialRegistryKey), &dict1, &status));
+  EXPECT_TRUE(RegistryDictEquals(dict1, empty));
+
+  // Safety check with kRegistryKey (dict should not be empty).
+  RegistryDict dict2;
+  ASSERT_TRUE(preg_parser::ReadFile(test_file, base::ASCIIToUTF16(kRegistryKey),
+                                    &dict2, &status));
+  EXPECT_FALSE(RegistryDictEquals(dict2, empty));
+}
+
 }  // namespace
 }  // namespace preg_parser
 }  // namespace policy