C++ Readability review for holte

components/rappor/rappor_metric_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// Change for readability
+
 #include "components/rappor/rappor_metric.h"
 
 #include <stdlib.h>
 
 #include "base/rand_util.h"
 #include "base/strings/stringprintf.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace rappor {
 
@@ skipping 19 matching lines @@
 TEST(RapporMetricTest, BasicMetric) {
   RapporMetric testMetric("MyRappor", kTestRapporParameters, 0);
   testMetric.AddSample("Foo");
   testMetric.AddSample("Bar");
   EXPECT_EQ(0x80, testMetric.bytes()[1]);
 }
 
 TEST(RapporMetricTest, GetReport) {
   RapporMetric metric("MyRappor", kTestRapporParameters, 0);
 
-  ByteVector report = metric.GetReport(
+  const ByteVector report = metric.GetReport(
       HmacByteVectorGenerator::GenerateEntropyInput());
   EXPECT_EQ(16u, report.size());
 }
 
 TEST(RapporMetricTest, GetReportStatistics) {
   RapporMetric metric("MyStatsRappor", kTestStatsRapporParameters, 0);
 
   for (char i = 0; i < 50; i++) {
     metric.AddSample(base::StringPrintf("%d", i));
   }
-  ByteVector real_bits = metric.bytes();
-  int real_bit_count = CountBits(real_bits);
+  const ByteVector real_bits = metric.bytes();
+  const int real_bit_count = CountBits(real_bits);
   EXPECT_EQ(real_bit_count, 152);
 
-  std::string secret = HmacByteVectorGenerator::GenerateEntropyInput();
-  ByteVector report = metric.GetReport(secret);
+  const std::string secret = HmacByteVectorGenerator::GenerateEntropyInput();
+  const ByteVector report = metric.GetReport(secret);
 
-  // For the bits we actually set in the bloom filter, get a count of how
+  // For the bits we actually set in the Bloom filter, get a count of how
   // many of them reported true.
   ByteVector from_true_reports = report;
   // Real bits AND report bits.
   ByteVectorMerge(real_bits, real_bits, &from_true_reports);
-  int true_from_true_count = CountBits(from_true_reports);
+  const int true_from_true_count = CountBits(from_true_reports);
 
-  // For the bits we didn't set in the bloom filter, get a count of how
+  // For the bits we didn't set in the Bloom filter, get a count of how
   // many of them reported true.
   ByteVector from_false_reports = report;
   ByteVectorOr(real_bits, &from_false_reports);
-  int true_from_false_count = CountBits(from_false_reports) - real_bit_count;
+  const int true_from_false_count =
+      CountBits(from_false_reports) - real_bit_count;
 
   // The probability of a true bit being true after redaction =
   //   [fake_prob]*[fake_true_prob] + (1-[fake_prob]) =
   //   .75 * .5 + (1-.75) = .625
   // The probablity of a false bit being true after redaction =
   //   [fake_prob]*[fake_true_prob] = .375
   // The probability of a bit reporting true =
   //   [redacted_prob] * [one_coin_prob:.75] +
   //      (1-[redacted_prob]) * [zero_coin_prob:.5] =
   //   0.65625 for true bits
   //   0.59375 for false bits
 
   // stats.binom(152, 0.65625).ppf(0.000005) = 73
   EXPECT_GT(true_from_true_count, 73);
   // stats.binom(152, 0.65625).ppf(0.999995) = 124
   EXPECT_LE(true_from_true_count, 124);
 
   // stats.binom(248, 0.59375).ppf(.000005) = 113
   EXPECT_GT(true_from_false_count, 113);
   // stats.binom(248, 0.59375).ppf(.999995) = 181
   EXPECT_LE(true_from_false_count, 181);
 }
 
 }  // namespace rappor