net/spdy/hpack_huffman_table_test.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/spdy/hpack_huffman_table.h"
   6
   7 #include <bitset>
   8 #include <string>
   9
  10 #include "base/logging.h"
  11 #include "net/spdy/hpack_constants.h"
  12 #include "net/spdy/hpack_input_stream.h"
  13 #include "net/spdy/hpack_output_stream.h"
  14 #include "net/spdy/spdy_test_utils.h"
  15 #include "testing/gmock/include/gmock/gmock.h"
  16 #include "testing/gtest/include/gtest/gtest.h"
  17
  18 using base::StringPiece;
  19 using net::test::a2b_hex;
  20 using std::string;
  21 using testing::ElementsAre;
  22 using testing::ElementsAreArray;
  23 using testing::Pointwise;
  24
  25 namespace net {
  26
  27 namespace test {
  28
  29 typedef HpackHuffmanTable::DecodeEntry DecodeEntry;
  30 typedef HpackHuffmanTable::DecodeTable DecodeTable;
  31
  32 class HpackHuffmanTablePeer {
  33  public:
  34   explicit HpackHuffmanTablePeer(const HpackHuffmanTable& table)
  35       : table_(table) { }
  36
  37   const std::vector<uint32>& code_by_id() const {
  38     return table_.code_by_id_;
  39   }
  40   const std::vector<uint8>& length_by_id() const {
  41     return table_.length_by_id_;
  42   }
  43   const std::vector<DecodeTable>& decode_tables() const {
  44     return table_.decode_tables_;
  45   }
  46   char pad_bits() const {
  47     // Cast to match signed-ness of bits8().
  48     return static_cast<char>(table_.pad_bits_);
  49   }
  50   uint16 failed_symbol_id() const {
  51     return table_.failed_symbol_id_;
  52   }
  53   std::vector<DecodeEntry> decode_entries(const DecodeTable& decode_table) {
  54     std::vector<DecodeEntry>::const_iterator begin =
  55         table_.decode_entries_.begin() + decode_table.entries_offset;
  56     return std::vector<DecodeEntry>(begin, begin + decode_table.size());
  57   }
  58   void DumpDecodeTable(const DecodeTable& table) {
  59     std::vector<DecodeEntry> entries = decode_entries(table);
  60     LOG(INFO) << "Table size " << (1 << table.indexed_length)
  61               << " prefix " << unsigned(table.prefix_length)
  62               << " indexed " << unsigned(table.indexed_length);
  63     size_t i = 0;
  64     while (i != table.size()) {
  65       const DecodeEntry& entry = entries[i];
  66       LOG(INFO) << i << ":"
  67                 << " next_table " << unsigned(entry.next_table_index)
  68                 << " length " << unsigned(entry.length)
  69                 << " symbol " << unsigned(entry.symbol_id);
  70       size_t j = 1;
  71       for (; (i + j) != table.size(); j++) {
  72         const DecodeEntry& next = entries[i + j];
  73         if (next.next_table_index != entry.next_table_index ||
  74             next.length != entry.length ||
  75             next.symbol_id != entry.symbol_id)
  76           break;
  77       }
  78       if (j > 1) {
  79         LOG(INFO) << "  (repeats " << j << " times)";
  80       }
  81       i += j;
  82     }
  83   }
  84
  85  private:
  86   const HpackHuffmanTable& table_;
  87 };
  88
  89 namespace {
  90
  91 class HpackHuffmanTableTest : public ::testing::Test {
  92  protected:
  93   HpackHuffmanTableTest()
  94       : table_(),
  95         peer_(table_) {}
  96
  97   string EncodeString(StringPiece input) {
  98     string result;
  99     HpackOutputStream output_stream;
 100     table_.EncodeString(input, &output_stream);
 101
 102     output_stream.TakeString(&result);
 103     // Verify EncodedSize() agrees with EncodeString().
 104     EXPECT_EQ(result.size(), table_.EncodedSize(input));
 105     return result;
 106   }
 107
 108   HpackHuffmanTable table_;
 109   HpackHuffmanTablePeer peer_;
 110 };
 111
 112 MATCHER(DecodeEntryEq, "") {
 113   const DecodeEntry& lhs = std::tr1::get<0>(arg);
 114   const DecodeEntry& rhs = std::tr1::get<1>(arg);
 115   return lhs.next_table_index == rhs.next_table_index &&
 116       lhs.length == rhs.length &&
 117       lhs.symbol_id == rhs.symbol_id;
 118 }
 119
 120 uint32 bits32(const string& bitstring) {
 121   return std::bitset<32>(bitstring).to_ulong();
 122 }
 123 char bits8(const string& bitstring) {
 124   return static_cast<char>(std::bitset<8>(bitstring).to_ulong());
 125 }
 126
 127 TEST_F(HpackHuffmanTableTest, InitializeHpackCode) {
 128   std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
 129   EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
 130   EXPECT_TRUE(table_.IsInitialized());
 131   EXPECT_EQ(peer_.pad_bits(), bits8("11111111"));  // First 8 bits of EOS.
 132 }
 133
 134 TEST_F(HpackHuffmanTableTest, InitializeEdgeCases) {
 135   {
 136     // Verify eight symbols can be encoded with 3 bits per symbol.
 137     HpackHuffmanSymbol code[] = {
 138       {bits32("00000000000000000000000000000000"), 3, 0},
 139       {bits32("00100000000000000000000000000000"), 3, 1},
 140       {bits32("01000000000000000000000000000000"), 3, 2},
 141       {bits32("01100000000000000000000000000000"), 3, 3},
 142       {bits32("10000000000000000000000000000000"), 3, 4},
 143       {bits32("10100000000000000000000000000000"), 3, 5},
 144       {bits32("11000000000000000000000000000000"), 3, 6},
 145       {bits32("11100000000000000000000000000000"), 8, 7}};
 146     HpackHuffmanTable table;
 147     EXPECT_TRUE(table.Initialize(code, arraysize(code)));
 148   }
 149   {
 150     // But using 2 bits with one symbol overflows the code.
 151     HpackHuffmanSymbol code[] = {
 152       {bits32("01000000000000000000000000000000"), 3, 0},
 153       {bits32("01100000000000000000000000000000"), 3, 1},
 154       {bits32("00000000000000000000000000000000"), 2, 2},
 155       {bits32("10000000000000000000000000000000"), 3, 3},
 156       {bits32("10100000000000000000000000000000"), 3, 4},
 157       {bits32("11000000000000000000000000000000"), 3, 5},
 158       {bits32("11100000000000000000000000000000"), 3, 6},
 159       {bits32("00000000000000000000000000000000"), 8, 7}};  // Overflow.
 160     HpackHuffmanTable table;
 161     EXPECT_FALSE(table.Initialize(code, arraysize(code)));
 162     EXPECT_EQ(7, HpackHuffmanTablePeer(table).failed_symbol_id());
 163   }
 164   {
 165     // Verify four symbols can be encoded with incremental bits per symbol.
 166     HpackHuffmanSymbol code[] = {
 167       {bits32("00000000000000000000000000000000"), 1, 0},
 168       {bits32("10000000000000000000000000000000"), 2, 1},
 169       {bits32("11000000000000000000000000000000"), 3, 2},
 170       {bits32("11100000000000000000000000000000"), 8, 3}};
 171     HpackHuffmanTable table;
 172     EXPECT_TRUE(table.Initialize(code, arraysize(code)));
 173   }
 174   {
 175     // But repeating a length overflows the code.
 176     HpackHuffmanSymbol code[] = {
 177       {bits32("00000000000000000000000000000000"), 1, 0},
 178       {bits32("10000000000000000000000000000000"), 2, 1},
 179       {bits32("11000000000000000000000000000000"), 2, 2},
 180       {bits32("00000000000000000000000000000000"), 8, 3}};  // Overflow.
 181     HpackHuffmanTable table;
 182     EXPECT_FALSE(table.Initialize(code, arraysize(code)));
 183     EXPECT_EQ(3, HpackHuffmanTablePeer(table).failed_symbol_id());
 184   }
 185   {
 186     // Symbol IDs must be assigned sequentially with no gaps.
 187     HpackHuffmanSymbol code[] = {
 188       {bits32("00000000000000000000000000000000"), 1, 0},
 189       {bits32("10000000000000000000000000000000"), 2, 1},
 190       {bits32("11000000000000000000000000000000"), 3, 1},  // Repeat.
 191       {bits32("11100000000000000000000000000000"), 8, 3}};
 192     HpackHuffmanTable table;
 193     EXPECT_FALSE(table.Initialize(code, arraysize(code)));
 194     EXPECT_EQ(2, HpackHuffmanTablePeer(table).failed_symbol_id());
 195   }
 196   {
 197     // Canonical codes must begin with zero.
 198     HpackHuffmanSymbol code[] = {
 199       {bits32("10000000000000000000000000000000"), 4, 0},
 200       {bits32("10010000000000000000000000000000"), 4, 1},
 201       {bits32("10100000000000000000000000000000"), 4, 2},
 202       {bits32("10110000000000000000000000000000"), 8, 3}};
 203     HpackHuffmanTable table;
 204     EXPECT_FALSE(table.Initialize(code, arraysize(code)));
 205     EXPECT_EQ(0, HpackHuffmanTablePeer(table).failed_symbol_id());
 206   }
 207   {
 208     // Codes must match the expected canonical sequence.
 209     HpackHuffmanSymbol code[] = {
 210       {bits32("00000000000000000000000000000000"), 2, 0},
 211       {bits32("01000000000000000000000000000000"), 2, 1},
 212       {bits32("11000000000000000000000000000000"), 2, 2},  // Not canonical.
 213       {bits32("10000000000000000000000000000000"), 8, 3}};
 214     HpackHuffmanTable table;
 215     EXPECT_FALSE(table.Initialize(code, arraysize(code)));
 216     EXPECT_EQ(2, HpackHuffmanTablePeer(table).failed_symbol_id());
 217   }
 218   {
 219     // At least one code must have a length of 8 bits (to ensure pad-ability).
 220     HpackHuffmanSymbol code[] = {
 221       {bits32("00000000000000000000000000000000"), 1, 0},
 222       {bits32("10000000000000000000000000000000"), 2, 1},
 223       {bits32("11000000000000000000000000000000"), 3, 2},
 224       {bits32("11100000000000000000000000000000"), 7, 3}};
 225     HpackHuffmanTable table;
 226     EXPECT_FALSE(table.Initialize(code, arraysize(code)));
 227   }
 228 }
 229
 230 TEST_F(HpackHuffmanTableTest, ValidateInternalsWithSmallCode) {
 231   HpackHuffmanSymbol code[] = {
 232     {bits32("01100000000000000000000000000000"), 4, 0},  // 3rd.
 233     {bits32("01110000000000000000000000000000"), 4, 1},  // 4th.
 234     {bits32("00000000000000000000000000000000"), 2, 2},  // 1st assigned code.
 235     {bits32("01000000000000000000000000000000"), 3, 3},  // 2nd.
 236     {bits32("10000000000000000000000000000000"), 5, 4},  // 5th.
 237     {bits32("10001000000000000000000000000000"), 5, 5},  // 6th.
 238     {bits32("10011000000000000000000000000000"), 8, 6},  // 8th.
 239     {bits32("10010000000000000000000000000000"), 5, 7}};  // 7th.
 240   EXPECT_TRUE(table_.Initialize(code, arraysize(code)));
 241   ASSERT_EQ(arraysize(code), peer_.code_by_id().size());
 242   ASSERT_EQ(arraysize(code), peer_.length_by_id().size());
 243   for (size_t i = 0; i < arraysize(code); ++i) {
 244     EXPECT_EQ(code[i].code, peer_.code_by_id()[i]);
 245     EXPECT_EQ(code[i].length, peer_.length_by_id()[i]);
 246   }
 247
 248   EXPECT_EQ(1u, peer_.decode_tables().size());
 249   {
 250     std::vector<DecodeEntry> expected;
 251     expected.resize(128, DecodeEntry(0, 2, 2));  // Fills 128.
 252     expected.resize(192, DecodeEntry(0, 3, 3));  // Fills 64.
 253     expected.resize(224, DecodeEntry(0, 4, 0));  // Fills 32.
 254     expected.resize(256, DecodeEntry(0, 4, 1));  // Fills 32.
 255     expected.resize(272, DecodeEntry(0, 5, 4));  // Fills 16.
 256     expected.resize(288, DecodeEntry(0, 5, 5));  // Fills 16.
 257     expected.resize(304, DecodeEntry(0, 5, 7));  // Fills 16.
 258     expected.resize(306, DecodeEntry(0, 8, 6));  // Fills 2.
 259     expected.resize(512, DecodeEntry());  // Remainder is empty.
 260
 261     EXPECT_THAT(peer_.decode_entries(peer_.decode_tables()[0]),
 262                 Pointwise(DecodeEntryEq(), expected));
 263   }
 264   EXPECT_EQ(bits8("10011000"), peer_.pad_bits());
 265
 266   char input_storage[] = {2, 3, 2, 7, 4};
 267   StringPiece input(input_storage, arraysize(input_storage));
 268   // By symbol: (2) 00 (3) 010 (2) 00 (7) 10010 (4) 10000 (6 as pad) 1001100.
 269   char expect_storage[] = {
 270     bits8("00010001"),
 271     bits8("00101000"),
 272     bits8("01001100")};
 273   StringPiece expect(expect_storage, arraysize(expect_storage));
 274
 275   string buffer_in = EncodeString(input);
 276   EXPECT_EQ(expect, buffer_in);
 277
 278   string buffer_out;
 279   HpackInputStream input_stream(kuint32max, buffer_in);
 280   EXPECT_TRUE(table_.DecodeString(&input_stream, input.size(),  &buffer_out));
 281   EXPECT_EQ(buffer_out, input);
 282 }
 283
 284 TEST_F(HpackHuffmanTableTest, ValidateMultiLevelDecodeTables) {
 285   HpackHuffmanSymbol code[] = {
 286     {bits32("00000000000000000000000000000000"), 6, 0},
 287     {bits32("00000100000000000000000000000000"), 6, 1},
 288     {bits32("00001000000000000000000000000000"), 11, 2},
 289     {bits32("00001000001000000000000000000000"), 11, 3},
 290     {bits32("00001000010000000000000000000000"), 12, 4},
 291   };
 292   EXPECT_TRUE(table_.Initialize(code, arraysize(code)));
 293
 294   EXPECT_EQ(2u, peer_.decode_tables().size());
 295   {
 296     std::vector<DecodeEntry> expected;
 297     expected.resize(8, DecodeEntry(0, 6, 0));  // Fills 8.
 298     expected.resize(16, DecodeEntry(0, 6, 1));  // Fills 8.
 299     expected.resize(17, DecodeEntry(1, 12, 0));  // Pointer. Fills 1.
 300     expected.resize(512, DecodeEntry());  // Remainder is empty.
 301
 302     const DecodeTable& decode_table = peer_.decode_tables()[0];
 303     EXPECT_EQ(decode_table.prefix_length, 0);
 304     EXPECT_EQ(decode_table.indexed_length, 9);
 305     EXPECT_THAT(peer_.decode_entries(decode_table),
 306                 Pointwise(DecodeEntryEq(), expected));
 307   }
 308   {
 309     std::vector<DecodeEntry> expected;
 310     expected.resize(2, DecodeEntry(1, 11, 2));  // Fills 2.
 311     expected.resize(4, DecodeEntry(1, 11, 3));  // Fills 2.
 312     expected.resize(5, DecodeEntry(1, 12, 4));  // Fills 1.
 313     expected.resize(8, DecodeEntry());  // Remainder is empty.
 314
 315     const DecodeTable& decode_table = peer_.decode_tables()[1];
 316     EXPECT_EQ(decode_table.prefix_length, 9);
 317     EXPECT_EQ(decode_table.indexed_length, 3);
 318     EXPECT_THAT(peer_.decode_entries(decode_table),
 319                 Pointwise(DecodeEntryEq(), expected));
 320   }
 321   EXPECT_EQ(bits8("00001000"), peer_.pad_bits());
 322 }
 323
 324 TEST_F(HpackHuffmanTableTest, DecodeWithBadInput) {
 325   HpackHuffmanSymbol code[] = {
 326     {bits32("01100000000000000000000000000000"), 4, 0},
 327     {bits32("01110000000000000000000000000000"), 4, 1},
 328     {bits32("00000000000000000000000000000000"), 2, 2},
 329     {bits32("01000000000000000000000000000000"), 3, 3},
 330     {bits32("10000000000000000000000000000000"), 5, 4},
 331     {bits32("10001000000000000000000000000000"), 5, 5},
 332     {bits32("10011000000000000000000000000000"), 6, 6},
 333     {bits32("10010000000000000000000000000000"), 5, 7},
 334     {bits32("10011100000000000000000000000000"), 16, 8}};
 335   EXPECT_TRUE(table_.Initialize(code, arraysize(code)));
 336
 337   string buffer;
 338   const size_t capacity = 4;
 339   {
 340     // This example works: (2) 00 (3) 010 (2) 00 (6) 100110 (pad) 100.
 341     char input_storage[] = {bits8("00010001"), bits8("00110100")};
 342     StringPiece input(input_storage, arraysize(input_storage));
 343
 344     HpackInputStream input_stream(kuint32max, input);
 345     EXPECT_TRUE(table_.DecodeString(&input_stream, capacity, &buffer));
 346     EXPECT_EQ(buffer, "\x02\x03\x02\x06");
 347   }
 348   {
 349     // Expect to fail on an invalid code prefix.
 350     // (2) 00 (3) 010 (2) 00 (too-large) 101000 (pad) 100.
 351     char input_storage[] = {bits8("00010001"), bits8("01000111")};
 352     StringPiece input(input_storage, arraysize(input_storage));
 353
 354     HpackInputStream input_stream(kuint32max, input);
 355     EXPECT_FALSE(table_.DecodeString(&input_stream, capacity, &buffer));
 356     EXPECT_EQ(buffer, "\x02\x03\x02");
 357   }
 358   {
 359     // Repeat the shortest 0b00 code to overflow |buffer|. Expect to fail.
 360     std::vector<char> input_storage(1 + capacity / 4, '\0');
 361     StringPiece input(&input_storage[0], input_storage.size());
 362
 363     HpackInputStream input_stream(kuint32max, input);
 364     EXPECT_FALSE(table_.DecodeString(&input_stream, capacity, &buffer));
 365
 366     std::vector<char> expected(capacity, '\x02');
 367     EXPECT_THAT(buffer, ElementsAreArray(expected));
 368     EXPECT_EQ(capacity, buffer.size());
 369   }
 370   {
 371     // Expect to fail if more than a byte of unconsumed input remains.
 372     // (6) 100110 (8 truncated) 1001110000
 373     char input_storage[] = {bits8("10011010"), bits8("01110000")};
 374     StringPiece input(input_storage, arraysize(input_storage));
 375
 376     HpackInputStream input_stream(kuint32max, input);
 377     EXPECT_FALSE(table_.DecodeString(&input_stream, capacity, &buffer));
 378     EXPECT_EQ(buffer, "\x06");
 379   }
 380 }
 381
 382 TEST_F(HpackHuffmanTableTest, SpecRequestExamples) {
 383   std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
 384   EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
 385
 386   string buffer;
 387   string test_table[] = {
 388     a2b_hex("f1e3c2e5f23a6ba0ab90f4ff"),
 389     "www.example.com",
 390     a2b_hex("a8eb10649cbf"),
 391     "no-cache",
 392     a2b_hex("25a849e95ba97d7f"),
 393     "custom-key",
 394     a2b_hex("25a849e95bb8e8b4bf"),
 395     "custom-value",
 396   };
 397   // Round-trip each test example.
 398   for (size_t i = 0; i != arraysize(test_table); i += 2) {
 399     const string& encodedFixture(test_table[i]);
 400     const string& decodedFixture(test_table[i+1]);
 401     HpackInputStream input_stream(kuint32max, encodedFixture);
 402
 403     EXPECT_TRUE(table_.DecodeString(&input_stream, decodedFixture.size(),
 404                                     &buffer));
 405     EXPECT_EQ(decodedFixture, buffer);
 406     buffer = EncodeString(decodedFixture);
 407     EXPECT_EQ(encodedFixture, buffer);
 408   }
 409 }
 410
 411 TEST_F(HpackHuffmanTableTest, SpecResponseExamples) {
 412   std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
 413   EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
 414
 415   string buffer;
 416   string test_table[] = {
 417     a2b_hex("6402"),
 418     "302",
 419     a2b_hex("aec3771a4b"),
 420     "private",
 421     a2b_hex("d07abe941054d444a8200595040b8166"
 422             "e082a62d1bff"),
 423     "Mon, 21 Oct 2013 20:13:21 GMT",
 424     a2b_hex("9d29ad171863c78f0b97c8e9ae82ae43"
 425             "d3"),
 426     "https://www.example.com",
 427     a2b_hex("94e7821dd7f2e6c7b335dfdfcd5b3960"
 428             "d5af27087f3672c1ab270fb5291f9587"
 429             "316065c003ed4ee5b1063d5007"),
 430     "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1",
 431   };
 432   // Round-trip each test example.
 433   for (size_t i = 0; i != arraysize(test_table); i += 2) {
 434     const string& encodedFixture(test_table[i]);
 435     const string& decodedFixture(test_table[i+1]);
 436     HpackInputStream input_stream(kuint32max, encodedFixture);
 437
 438     EXPECT_TRUE(table_.DecodeString(&input_stream, decodedFixture.size(),
 439                                     &buffer));
 440     EXPECT_EQ(decodedFixture, buffer);
 441     buffer = EncodeString(decodedFixture);
 442     EXPECT_EQ(encodedFixture, buffer);
 443   }
 444 }
 445
 446 TEST_F(HpackHuffmanTableTest, RoundTripIndvidualSymbols) {
 447   std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
 448   EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
 449
 450   for (size_t i = 0; i != 256; i++) {
 451     char c = static_cast<char>(i);
 452     char storage[3] = {c, c, c};
 453     StringPiece input(storage, arraysize(storage));
 454
 455     string buffer_in = EncodeString(input);
 456     string buffer_out;
 457
 458     HpackInputStream input_stream(kuint32max, buffer_in);
 459     EXPECT_TRUE(table_.DecodeString(&input_stream, input.size(), &buffer_out));
 460     EXPECT_EQ(input, buffer_out);
 461   }
 462 }
 463
 464 TEST_F(HpackHuffmanTableTest, RoundTripSymbolSequence) {
 465   std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
 466   EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
 467
 468
 469   char storage[512];
 470   for (size_t i = 0; i != 256; i++) {
 471     storage[i] = static_cast<char>(i);
 472     storage[511 - i] = static_cast<char>(i);
 473   }
 474   StringPiece input(storage, arraysize(storage));
 475
 476   string buffer_in = EncodeString(input);
 477   string buffer_out;
 478
 479   HpackInputStream input_stream(kuint32max, buffer_in);
 480   EXPECT_TRUE(table_.DecodeString(&input_stream, input.size(), &buffer_out));
 481   EXPECT_EQ(input, buffer_out);
 482 }
 483
 484 TEST_F(HpackHuffmanTableTest, EncodedSizeAgreesWithEncodeString) {
 485   std::vector<HpackHuffmanSymbol> code = HpackHuffmanCode();
 486   EXPECT_TRUE(table_.Initialize(&code[0], code.size()));
 487
 488   string test_table[] = {
 489     "",
 490     "Mon, 21 Oct 2013 20:13:21 GMT",
 491     "https://www.example.com",
 492     "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1",
 493     string(1, '\0'),
 494     string("foo\0bar", 7),
 495     string(256, '\0'),
 496   };
 497   for (size_t i = 0; i != 256; ++i) {
 498     // Expand last |test_table| entry to cover all codes.
 499     test_table[arraysize(test_table)-1][i] = static_cast<char>(i);
 500   }
 501
 502   HpackOutputStream output_stream;
 503   string encoding;
 504   for (size_t i = 0; i != arraysize(test_table); ++i) {
 505     table_.EncodeString(test_table[i], &output_stream);
 506     output_stream.TakeString(&encoding);
 507     EXPECT_EQ(encoding.size(), table_.EncodedSize(test_table[i]));
 508   }
 509 }
 510
 511 }  // namespace
 512
 513 }  // namespace test
 514
 515 }  // namespace net