Add a minimum byte count to metrics log serialization

chrome/browser/metrics/metrics_log_serializer_unittest.cc

Index: chrome/browser/metrics/metrics_log_serializer_unittest.cc
diff --git a/chrome/browser/metrics/metrics_log_serializer_unittest.cc b/chrome/browser/metrics/metrics_log_serializer_unittest.cc
index f023a7cb2ef0b119f2f49a6dbbe8197d75a6bc44..bb2a952123fab8445dd7e8f12a1d0a623b8fbb40 100644
--- a/chrome/browser/metrics/metrics_log_serializer_unittest.cc
+++ b/chrome/browser/metrics/metrics_log_serializer_unittest.cc
@@ -12,7 +12,7 @@ typedef MetricsLogManager::SerializedLog SerializedLog;
 
 namespace {
 
-const size_t kMaxLocalListSize = 3;
+const size_t kMaxLogByteTotal = 1000;
 
 }  // namespace
 
@@ -24,7 +24,7 @@ TEST(MetricsLogSerializerTest, EmptyLogList) {
   ListValue list;
   std::vector<SerializedLog> local_list;
 
-  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLocalListSize,
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
                                             &list);
   EXPECT_EQ(0U, list.GetSize());
 
@@ -42,7 +42,7 @@ TEST(MetricsLogSerializerTest, SingleElementLogList) {
   std::vector<SerializedLog> local_list(1);
   local_list[0].xml = "Hello world!";
 
-  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLocalListSize,
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
                                             &list);
 
   // |list| will now contain the following:
@@ -76,40 +76,75 @@ TEST(MetricsLogSerializerTest, SingleElementLogList) {
   EXPECT_EQ(1U, local_list.size());
 }
 
-// Store elements greater than the limit.
+// Store a set of logs larger than the limit.
 TEST(MetricsLogSerializerTest, OverLimitLogList) {
   ListValue list;
 
+  // Make log_count logs each slightly larger that TotalByteLimit / log_count
+  // so that the oldest (first) log won't fit.
   std::vector<SerializedLog> local_list(4);
-  local_list[0].proto = "one";
-  local_list[1].proto = "two";
-  local_list[2].proto = "three";
-  local_list[3].proto = "four";
-
-  std::string expected_first;
-  base::Base64Encode(local_list[local_list.size() - kMaxLocalListSize].proto,
-                     &expected_first);
-  std::string expected_last;
-  base::Base64Encode(local_list[local_list.size() - 1].proto,
-                     &expected_last);
-
-  MetricsLogSerializer::WriteLogsToPrefList(local_list, false,
-                                            kMaxLocalListSize, &list);
-  EXPECT_EQ(kMaxLocalListSize + 2, list.GetSize());
-
-  std::string actual_first;
-  EXPECT_TRUE((*(list.begin() + 1))->GetAsString(&actual_first));
-  EXPECT_EQ(expected_first, actual_first);
-
-  std::string actual_last;
-  EXPECT_TRUE((*(list.end() - 2))->GetAsString(&actual_last));
-  EXPECT_EQ(expected_last, actual_last);
+  size_t log_size = (kMaxLogByteTotal / local_list.size()) + 2;
+  local_list[0].xml = "one";
+  local_list[1].xml = "two";
+  local_list[2].xml = "three";
+  local_list[3].xml = "four";
+  for (size_t i = 0; i < local_list.size(); ++i) {
+    local_list[i].xml.resize(log_size, ' ');
+  }
 
-  local_list.clear();
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
+                                            &list);
+  std::vector<SerializedLog> result_list;
   EXPECT_EQ(
       MetricsLogSerializer::RECALL_SUCCESS,
-      MetricsLogSerializer::ReadLogsFromPrefList(list, true, &local_list));
-  EXPECT_EQ(kMaxLocalListSize, local_list.size());
+      MetricsLogSerializer::ReadLogsFromPrefList(list, true, &result_list));
+  EXPECT_EQ(local_list.size() - 1, result_list.size());
+
+  EXPECT_TRUE(result_list.front().xml.find("two") == 0);
+  EXPECT_TRUE(result_list.back().xml.find("four") == 0);
+}
+
+// Store a log larger than the limit.
+TEST(MetricsLogSerializerTest, OverLimitIndividualLog) {
+  ListValue list;
+
+  std::vector<SerializedLog> local_list(4);
+  local_list[0].xml = "one";
+  local_list[1].xml = "two";
+  local_list[2].xml = "three";
+  local_list[2].xml.resize(kMaxLogByteTotal + 1, ' ');
+  local_list[3].xml = "four";
+
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
+                                            &list);
+  std::vector<SerializedLog> result_list;
+  EXPECT_EQ(
+      MetricsLogSerializer::RECALL_SUCCESS,
+      MetricsLogSerializer::ReadLogsFromPrefList(list, true, &result_list));
+  EXPECT_EQ(local_list.size() - 1, result_list.size());
+
+  for (size_t i = 0; i < result_list.size(); ++i) {
+    EXPECT_LT(result_list[i].xml.size(), kMaxLogByteTotal);
+  }
+}
+
+// Store a set of logs each of which is larger than the limit.
+TEST(MetricsLogSerializerTest, OverLimitAllLogs) {
+  ListValue list;
+
+  std::vector<SerializedLog> local_list(2);
+  size_t log_size = kMaxLogByteTotal + 1;
+  for (size_t i = 0; i < local_list.size(); ++i) {
+    local_list[i].xml.resize(log_size, ' ');
+  }
+
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
+                                            &list);
+  std::vector<SerializedLog> result_list;
+  EXPECT_EQ(
+      MetricsLogSerializer::LIST_EMPTY,
+      MetricsLogSerializer::ReadLogsFromPrefList(list, true, &result_list));
+  EXPECT_EQ(0U, result_list.size());
 }
 
 // Induce LIST_SIZE_TOO_SMALL corruption
@@ -119,7 +154,7 @@ TEST(MetricsLogSerializerTest, SmallRecoveredListSize) {
   std::vector<SerializedLog> local_list(1);
   local_list[0].xml = "Hello world!";
 
-  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLocalListSize,
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
                                             &list);
   EXPECT_EQ(3U, list.GetSize());
 
@@ -141,7 +176,7 @@ TEST(MetricsLogSerializerTest, RemoveSizeFromLogList) {
   local_list[0].xml = "one";
   local_list[1].xml = "two";
   EXPECT_EQ(2U, local_list.size());
-  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLocalListSize,
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
                                             &list);
   EXPECT_EQ(4U, list.GetSize());
 
@@ -161,7 +196,7 @@ TEST(MetricsLogSerializerTest, CorruptSizeOfLogList) {
   std::vector<SerializedLog> local_list(1);
   local_list[0].xml = "Hello world!";
 
-  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLocalListSize,
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
                                             &list);
   EXPECT_EQ(3U, list.GetSize());
 
@@ -182,7 +217,7 @@ TEST(MetricsLogSerializerTest, CorruptChecksumOfLogList) {
   std::vector<SerializedLog> local_list(1);
   local_list[0].xml = "Hello world!";
 
-  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLocalListSize,
+  MetricsLogSerializer::WriteLogsToPrefList(local_list, true, kMaxLogByteTotal,
                                             &list);
   EXPECT_EQ(3U, list.GetSize());