llvm/unittests/Support/JSONTest.cpp

   1 //===-- JSONTest.cpp - JSON unit tests --------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/Support/JSON.h"
  10 #include "llvm/Support/raw_ostream.h"
  11 #include "llvm/Testing/Support/Error.h"
  12
  13 #include "gmock/gmock.h"
  14 #include "gtest/gtest.h"
  15
  16 namespace llvm {
  17 namespace json {
  18
  19 namespace {
  20
  21 std::string s(const Value &E) { return llvm::formatv("{0}", E).str(); }
  22 std::string sp(const Value &E) { return llvm::formatv("{0:2}", E).str(); }
  23
  24 TEST(JSONTest, Types) {
  25   EXPECT_EQ("true", s(true));
  26   EXPECT_EQ("null", s(nullptr));
  27   EXPECT_EQ("2.5", s(2.5));
  28   EXPECT_EQ(R"("foo")", s("foo"));
  29   EXPECT_EQ("[1,2,3]", s({1, 2, 3}));
  30   EXPECT_EQ(R"({"x":10,"y":20})", s(Object{{"x", 10}, {"y", 20}}));
  31
  32 #ifdef NDEBUG
  33   EXPECT_EQ(R"("��")", s("\xC0\x80"));
  34   EXPECT_EQ(R"({"��":0})", s(Object{{"\xC0\x80", 0}}));
  35 #else
  36   EXPECT_DEATH(s("\xC0\x80"), "Invalid UTF-8");
  37   EXPECT_DEATH(s(Object{{"\xC0\x80", 0}}), "Invalid UTF-8");
  38 #endif
  39 }
  40
  41 TEST(JSONTest, Constructors) {
  42   // Lots of edge cases around empty and singleton init lists.
  43   EXPECT_EQ("[[[3]]]", s({{{3}}}));
  44   EXPECT_EQ("[[[]]]", s({{{}}}));
  45   EXPECT_EQ("[[{}]]", s({{Object{}}}));
  46   EXPECT_EQ(R"({"A":{"B":{}}})", s(Object{{"A", Object{{"B", Object{}}}}}));
  47   EXPECT_EQ(R"({"A":{"B":{"X":"Y"}}})",
  48             s(Object{{"A", Object{{"B", Object{{"X", "Y"}}}}}}));
  49   EXPECT_EQ("null", s(std::optional<double>()));
  50   EXPECT_EQ("2.5", s(std::optional<double>(2.5)));
  51   EXPECT_EQ("[[2.5,null]]", s(std::vector<std::vector<std::optional<double>>>{
  52                                 {2.5, std::nullopt}}));
  53 }
  54
  55 TEST(JSONTest, StringOwnership) {
  56   char X[] = "Hello";
  57   Value Alias = static_cast<const char *>(X);
  58   X[1] = 'a';
  59   EXPECT_EQ(R"("Hallo")", s(Alias));
  60
  61   std::string Y = "Hello";
  62   Value Copy = Y;
  63   Y[1] = 'a';
  64   EXPECT_EQ(R"("Hello")", s(Copy));
  65 }
  66
  67 TEST(JSONTest, CanonicalOutput) {
  68   // Objects are sorted (but arrays aren't)!
  69   EXPECT_EQ(R"({"a":1,"b":2,"c":3})", s(Object{{"a", 1}, {"c", 3}, {"b", 2}}));
  70   EXPECT_EQ(R"(["a","c","b"])", s({"a", "c", "b"}));
  71   EXPECT_EQ("3", s(3.0));
  72 }
  73
  74 TEST(JSONTest, Escaping) {
  75   std::string Test = {
  76       0,                    // Strings may contain nulls.
  77       '\b',   '\f',         // Have mnemonics, but we escape numerically.
  78       '\r',   '\n',   '\t', // Escaped with mnemonics.
  79       'S',    '\"',   '\\', // Printable ASCII characters.
  80       '\x7f',               // Delete is not escaped.
  81       '\xce', '\x94',       // Non-ASCII UTF-8 is not escaped.
  82   };
  83
  84   std::string TestString = R"("\u0000\u0008\u000c\r\n\tS\"\\)"
  85                            "\x7f\xCE\x94\"";
  86
  87   EXPECT_EQ(TestString, s(Test));
  88
  89   EXPECT_EQ(R"({"object keys are\nescaped":true})",
  90             s(Object{{"object keys are\nescaped", true}}));
  91 }
  92
  93 TEST(JSONTest, PrettyPrinting) {
  94   const char Str[] = R"({
  95   "empty_array": [],
  96   "empty_object": {},
  97   "full_array": [
  98     1,
  99     null
 100   ],
 101   "full_object": {
 102     "nested_array": [
 103       {
 104         "property": "value"
 105       }
 106     ]
 107   }
 108 })";
 109
 110   EXPECT_EQ(Str, sp(Object{
 111                      {"empty_object", Object{}},
 112                      {"empty_array", {}},
 113                      {"full_array", {1, nullptr}},
 114                      {"full_object",
 115                       Object{
 116                           {"nested_array",
 117                            {Object{
 118                                {"property", "value"},
 119                            }}},
 120                       }},
 121                  }));
 122 }
 123
 124 TEST(JSONTest, Array) {
 125   Array A{1, 2};
 126   A.emplace_back(3);
 127   A.emplace(++A.begin(), 0);
 128   A.push_back(4);
 129   A.insert(++++A.begin(), 99);
 130
 131   EXPECT_EQ(A.size(), 6u);
 132   EXPECT_EQ(R"([1,0,99,2,3,4])", s(std::move(A)));
 133 }
 134
 135 TEST(JSONTest, Object) {
 136   Object O{{"a", 1}, {"b", 2}, {"c", 3}};
 137   EXPECT_TRUE(O.try_emplace("d", 4).second);
 138   EXPECT_FALSE(O.try_emplace("a", 4).second);
 139
 140   auto D = O.find("d");
 141   EXPECT_NE(D, O.end());
 142   auto E = O.find("e");
 143   EXPECT_EQ(E, O.end());
 144
 145   O.erase("b");
 146   O.erase(D);
 147   EXPECT_EQ(O.size(), 2u);
 148   EXPECT_EQ(R"({"a":1,"c":3})", s(std::move(O)));
 149 }
 150
 151 TEST(JSONTest, Parse) {
 152   auto Compare = [](llvm::StringRef S, Value Expected) {
 153     if (auto E = parse(S)) {
 154       // Compare both string forms and with operator==, in case we have bugs.
 155       EXPECT_EQ(*E, Expected);
 156       EXPECT_EQ(sp(*E), sp(Expected));
 157     } else {
 158       handleAllErrors(E.takeError(), [S](const llvm::ErrorInfoBase &E) {
 159         FAIL() << "Failed to parse JSON >>> " << S << " <<<: " << E.message();
 160       });
 161     }
 162   };
 163
 164   Compare(R"(true)", true);
 165   Compare(R"(false)", false);
 166   Compare(R"(null)", nullptr);
 167
 168   Compare(R"(42)", 42);
 169   Compare(R"(2.5)", 2.5);
 170   Compare(R"(2e50)", 2e50);
 171   Compare(R"(1.2e3456789)", std::numeric_limits<double>::infinity());
 172
 173   Compare(R"("foo")", "foo");
 174   Compare(R"("\"\\\b\f\n\r\t")", "\"\\\b\f\n\r\t");
 175   Compare(R"("\u0000")", llvm::StringRef("\0", 1));
 176   Compare("\"\x7f\"", "\x7f");
 177   Compare(R"("\ud801\udc37")", // UTF-16 surrogate pair escape.
 178           /*U+10437*/ "\xf0\x90\x90\xb7");
 179   Compare("\"\xE2\x82\xAC\xF0\x9D\x84\x9E\"", // UTF-8
 180           /*U+20AC U+1D11E*/ "\xe2\x82\xac\xf0\x9d\x84\x9e");
 181   Compare(
 182       // Invalid unicode.
 183       R"("LoneLeading=\ud801, LoneTrailing=\udc01, LeadLeadTrail=\ud801\ud801\udc37")",
 184       "LoneLeading=" /*U+FFFD*/ "\xef\xbf\xbd, "
 185       "LoneTrailing=" /*U+FFFD*/ "\xef\xbf\xbd, "
 186       "LeadLeadTrail=" /*U+FFFD U+10437*/ "\xef\xbf\xbd\xf0\x90\x90\xb7");
 187
 188   Compare(R"({"":0,"":0})", Object{{"", 0}});
 189   Compare(R"({"obj":{},"arr":[]})", Object{{"obj", Object{}}, {"arr", {}}});
 190   Compare(R"({"\n":{"\u0000":[[[[]]]]}})",
 191           Object{{"\n", Object{
 192                             {llvm::StringRef("\0", 1), {{{{}}}}},
 193                         }}});
 194   Compare("\r[\n\t] ", {});
 195 }
 196
 197 TEST(JSONTest, ParseErrors) {
 198   auto ExpectErr = [](llvm::StringRef Msg, llvm::StringRef S) {
 199     if (auto E = parse(S)) {
 200       // Compare both string forms and with operator==, in case we have bugs.
 201       FAIL() << "Parsed JSON >>> " << S << " <<< but wanted error: " << Msg;
 202     } else {
 203       handleAllErrors(E.takeError(), [S, Msg](const llvm::ErrorInfoBase &E) {
 204         EXPECT_THAT(E.message(), testing::HasSubstr(std::string(Msg))) << S;
 205       });
 206     }
 207   };
 208   ExpectErr("Unexpected EOF", "");
 209   ExpectErr("Unexpected EOF", "[");
 210   ExpectErr("Text after end of document", "[][]");
 211   ExpectErr("Invalid JSON value (false?)", "fuzzy");
 212   ExpectErr("Expected , or ]", "[2?]");
 213   ExpectErr("Expected object key", "{a:2}");
 214   ExpectErr("Expected : after object key", R"({"a",2})");
 215   ExpectErr("Expected , or } after object property", R"({"a":2 "b":3})");
 216   ExpectErr("Invalid JSON value", R"([&%!])");
 217   ExpectErr("Invalid JSON value (number?)", "1e1.0");
 218   ExpectErr("Unterminated string", R"("abc\"def)");
 219   ExpectErr("Control character in string", "\"abc\ndef\"");
 220   ExpectErr("Invalid escape sequence", R"("\030")");
 221   ExpectErr("Invalid \\u escape sequence", R"("\usuck")");
 222   ExpectErr("[3:3, byte=19]", R"({
 223   "valid": 1,
 224   invalid: 2
 225 })");
 226   ExpectErr("Invalid UTF-8 sequence", "\"\xC0\x80\""); // WTF-8 null
 227 }
 228
 229 // Direct tests of isUTF8 and fixUTF8. Internal uses are also tested elsewhere.
 230 TEST(JSONTest, UTF8) {
 231   for (const char *Valid : {
 232            "this is ASCII text",
 233            "thïs tëxt häs BMP chäräctërs",
 234            "𐌶𐌰L𐌾𐍈 C𐍈𐌼𐌴𐍃",
 235        }) {
 236     EXPECT_TRUE(isUTF8(Valid)) << Valid;
 237     EXPECT_EQ(fixUTF8(Valid), Valid);
 238   }
 239   for (auto Invalid : std::vector<std::pair<const char *, const char *>>{
 240            {"lone trailing \x81\x82 bytes", "lone trailing �� bytes"},
 241            {"missing trailing \xD0 bytes", "missing trailing � bytes"},
 242            {"truncated character \xD0", "truncated character �"},
 243            {"not \xC1\x80 the \xE0\x9f\xBF shortest \xF0\x83\x83\x83 encoding",
 244             "not �� the ��� shortest ���� encoding"},
 245            {"too \xF9\x80\x80\x80\x80 long", "too ����� long"},
 246            {"surrogate \xED\xA0\x80 invalid \xF4\x90\x80\x80",
 247             "surrogate ��� invalid ����"}}) {
 248     EXPECT_FALSE(isUTF8(Invalid.first)) << Invalid.first;
 249     EXPECT_EQ(fixUTF8(Invalid.first), Invalid.second);
 250   }
 251 }
 252
 253 TEST(JSONTest, Inspection) {
 254   llvm::Expected<Value> Doc = parse(R"(
 255     {
 256       "null": null,
 257       "boolean": false,
 258       "number": 2.78,
 259       "string": "json",
 260       "array": [null, true, 3.14, "hello", [1,2,3], {"time": "arrow"}],
 261       "object": {"fruit": "banana"}
 262     }
 263   )");
 264   EXPECT_TRUE(!!Doc);
 265
 266   Object *O = Doc->getAsObject();
 267   ASSERT_TRUE(O);
 268
 269   EXPECT_FALSE(O->getNull("missing"));
 270   EXPECT_FALSE(O->getNull("boolean"));
 271   EXPECT_TRUE(O->getNull("null"));
 272
 273   EXPECT_EQ(O->getNumber("number"), std::optional<double>(2.78));
 274   EXPECT_FALSE(O->getInteger("number"));
 275   EXPECT_EQ(O->getString("string"), std::optional<llvm::StringRef>("json"));
 276   ASSERT_FALSE(O->getObject("missing"));
 277   ASSERT_FALSE(O->getObject("array"));
 278   ASSERT_TRUE(O->getObject("object"));
 279   EXPECT_EQ(*O->getObject("object"), (Object{{"fruit", "banana"}}));
 280
 281   Array *A = O->getArray("array");
 282   ASSERT_TRUE(A);
 283   EXPECT_EQ((*A)[1].getAsBoolean(), std::optional<bool>(true));
 284   ASSERT_TRUE((*A)[4].getAsArray());
 285   EXPECT_EQ(*(*A)[4].getAsArray(), (Array{1, 2, 3}));
 286   EXPECT_EQ((*(*A)[4].getAsArray())[1].getAsInteger(),
 287             std::optional<int64_t>(2));
 288   int I = 0;
 289   for (Value &E : *A) {
 290     if (I++ == 5) {
 291       ASSERT_TRUE(E.getAsObject());
 292       EXPECT_EQ(E.getAsObject()->getString("time"),
 293                 std::optional<llvm::StringRef>("arrow"));
 294     } else
 295       EXPECT_FALSE(E.getAsObject());
 296   }
 297 }
 298
 299 // Verify special integer handling - we try to preserve exact int64 values.
 300 TEST(JSONTest, Integers) {
 301   struct {
 302     const char *Desc;
 303     Value Val;
 304     const char *Str;
 305     std::optional<int64_t> AsInt;
 306     std::optional<double> AsNumber;
 307   } TestCases[] = {
 308     {
 309         "Non-integer. Stored as double, not convertible.",
 310         double{1.5},
 311         "1.5",
 312         std::nullopt,
 313         1.5,
 314     },
 315
 316     {
 317         "Integer, not exact double. Stored as int64, convertible.",
 318         int64_t{0x4000000000000001},
 319         "4611686018427387905",
 320         int64_t{0x4000000000000001},
 321         double{0x4000000000000000},
 322     },
 323
 324     {
 325         "Negative integer, not exact double. Stored as int64, convertible.",
 326         int64_t{-0x4000000000000001},
 327         "-4611686018427387905",
 328         int64_t{-0x4000000000000001},
 329         double{-0x4000000000000000},
 330     },
 331
 332       // PR46470,
 333       // https://developercommunity.visualstudio.com/content/problem/1093399/incorrect-result-when-printing-6917529027641081856.html
 334 #if !defined(_MSC_VER) || _MSC_VER < 1926
 335     {
 336         "Dynamically exact integer. Stored as double, convertible.",
 337         double{0x6000000000000000},
 338         "6.9175290276410819e+18",
 339         int64_t{0x6000000000000000},
 340         double{0x6000000000000000},
 341     },
 342 #endif
 343
 344     {
 345         "Dynamically integer, >64 bits. Stored as double, not convertible.",
 346         1.5 * double{0x8000000000000000},
 347         "1.3835058055282164e+19",
 348         std::nullopt,
 349         1.5 * double{0x8000000000000000},
 350     },
 351   };
 352   for (const auto &T : TestCases) {
 353     EXPECT_EQ(T.Str, s(T.Val)) << T.Desc;
 354     llvm::Expected<Value> Doc = parse(T.Str);
 355     EXPECT_TRUE(!!Doc) << T.Desc;
 356     EXPECT_EQ(Doc->getAsInteger(), T.AsInt) << T.Desc;
 357     EXPECT_EQ(Doc->getAsNumber(), T.AsNumber) << T.Desc;
 358     EXPECT_EQ(T.Val, *Doc) << T.Desc;
 359     EXPECT_EQ(T.Str, s(*Doc)) << T.Desc;
 360   }
 361 }
 362
 363 // Verify uint64_t type.
 364 TEST(JSONTest, U64Integers) {
 365   Value Val = uint64_t{3100100100};
 366   uint64_t Var = 3100100100;
 367   EXPECT_EQ(Val, Var);
 368
 369   Val = uint64_t{std::numeric_limits<uint64_t>::max()};
 370   Var = std::numeric_limits<uint64_t>::max();
 371   EXPECT_EQ(Val, Var);
 372
 373   // Test the parse() part.
 374   {
 375     const char *Str = "4611686018427387905";
 376     llvm::Expected<Value> Doc = parse(Str);
 377
 378     EXPECT_TRUE(!!Doc);
 379     EXPECT_EQ(Doc->getAsInteger(), int64_t{4611686018427387905});
 380     EXPECT_EQ(Doc->getAsUINT64(), uint64_t{4611686018427387905});
 381   }
 382
 383   {
 384     const char *Str = "-78278238238328222";
 385     llvm::Expected<Value> Doc = parse(Str);
 386
 387     EXPECT_TRUE(!!Doc);
 388     EXPECT_EQ(Doc->getAsInteger(), int64_t{-78278238238328222});
 389     EXPECT_EQ(Doc->getAsUINT64(), std::nullopt);
 390   }
 391
 392   // Test with the largest 64 signed int.
 393   {
 394     const char *Str = "9223372036854775807";
 395     llvm::Expected<Value> Doc = parse(Str);
 396
 397     EXPECT_TRUE(!!Doc);
 398     EXPECT_EQ(Doc->getAsInteger(), int64_t{9223372036854775807});
 399     EXPECT_EQ(Doc->getAsUINT64(), uint64_t{9223372036854775807});
 400   }
 401
 402   // Test with the largest 64 unsigned int.
 403   {
 404     const char *Str = "18446744073709551615";
 405     llvm::Expected<Value> Doc = parse(Str);
 406
 407     EXPECT_TRUE(!!Doc);
 408     EXPECT_EQ(Doc->getAsInteger(), std::nullopt);
 409     EXPECT_EQ(Doc->getAsUINT64(), uint64_t{18446744073709551615u});
 410   }
 411
 412   // Test with a number that is too big for 64 bits.
 413   {
 414     const char *Str = "184467440737095516150";
 415     llvm::Expected<Value> Doc = parse(Str);
 416
 417     EXPECT_TRUE(!!Doc);
 418     EXPECT_EQ(Doc->getAsInteger(), std::nullopt);
 419     EXPECT_EQ(Doc->getAsUINT64(), std::nullopt);
 420     // The number was parsed as a double.
 421     EXPECT_TRUE(!!Doc->getAsNumber());
 422   }
 423
 424   // Test with a negative number that is too small for 64 bits.
 425   {
 426     const char *Str = "-18446744073709551615";
 427     llvm::Expected<Value> Doc = parse(Str);
 428
 429     EXPECT_TRUE(!!Doc);
 430     EXPECT_EQ(Doc->getAsInteger(), std::nullopt);
 431     EXPECT_EQ(Doc->getAsUINT64(), std::nullopt);
 432     // The number was parsed as a double.
 433     EXPECT_TRUE(!!Doc->getAsNumber());
 434   }
 435   // Test with a large number that is malformed.
 436   {
 437     const char *Str = "184467440737095516150.12.12";
 438     llvm::Expected<Value> Doc = parse(Str);
 439
 440     EXPECT_EQ("[1:27, byte=27]: Invalid JSON value (number?)",
 441               llvm::toString(Doc.takeError()));
 442   }
 443 }
 444
 445 template <typename T> void checkCppIntegers() {
 446   Value Val = T{10};
 447   T Var = 10;
 448   EXPECT_EQ(Val, Var);
 449
 450   Val = T{std::numeric_limits<T>::max()};
 451   Var = std::numeric_limits<T>::max();
 452   EXPECT_EQ(Val, Var);
 453
 454   Val = T{std::numeric_limits<T>::min()};
 455   Var = std::numeric_limits<T>::min();
 456   EXPECT_EQ(Val, Var);
 457 }
 458
 459 // Test that underlying C++ integer types behave as expected.
 460 TEST(JSONTest, CppIntegers) {
 461   checkCppIntegers<char>();
 462   checkCppIntegers<signed char>();
 463   checkCppIntegers<unsigned char>();
 464
 465   checkCppIntegers<short>();
 466   checkCppIntegers<unsigned short>();
 467
 468   checkCppIntegers<int>();
 469   checkCppIntegers<unsigned int>();
 470
 471   checkCppIntegers<long>();
 472   checkCppIntegers<unsigned long>();
 473
 474   checkCppIntegers<long long>();
 475   checkCppIntegers<unsigned long long>();
 476 }
 477
 478 // Sample struct with typical JSON-mapping rules.
 479 struct CustomStruct {
 480   CustomStruct() : B(false) {}
 481   CustomStruct(std::string S, std::optional<int> I, bool B)
 482       : S(S), I(I), B(B) {}
 483   std::string S;
 484   std::optional<int> I;
 485   bool B;
 486 };
 487 inline bool operator==(const CustomStruct &L, const CustomStruct &R) {
 488   return L.S == R.S && L.I == R.I && L.B == R.B;
 489 }
 490 inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
 491                                      const CustomStruct &S) {
 492   return OS << "(" << S.S << ", " << (S.I ? std::to_string(*S.I) : "None")
 493             << ", " << S.B << ")";
 494 }
 495 bool fromJSON(const Value &E, CustomStruct &R, Path P) {
 496   ObjectMapper O(E, P);
 497   return O && O.map("str", R.S) && O.map("int", R.I) &&
 498          O.mapOptional("bool", R.B);
 499 }
 500
 501 static std::string errorContext(const Value &V, const Path::Root &R) {
 502   std::string Context;
 503   llvm::raw_string_ostream OS(Context);
 504   R.printErrorContext(V, OS);
 505   return OS.str();
 506 }
 507
 508 TEST(JSONTest, Deserialize) {
 509   std::map<std::string, std::vector<CustomStruct>> R;
 510   CustomStruct ExpectedStruct = {"foo", 42, true};
 511   std::map<std::string, std::vector<CustomStruct>> Expected;
 512   Value J = Object{{"foo", Array{
 513                                Object{
 514                                    {"str", "foo"},
 515                                    {"int", 42},
 516                                    {"bool", true},
 517                                    {"unknown", "ignored"},
 518                                },
 519                                Object{{"str", "bar"}},
 520                            }}};
 521   Expected["foo"] = {
 522       CustomStruct("foo", 42, true),
 523       CustomStruct("bar", std::nullopt, false),
 524   };
 525   Path::Root Root("CustomStruct");
 526   ASSERT_TRUE(fromJSON(J, R, Root));
 527   EXPECT_EQ(R, Expected);
 528
 529   (*J.getAsObject()->getArray("foo"))[0] = 123;
 530   ASSERT_FALSE(fromJSON(J, R, Root));
 531   EXPECT_EQ("expected object at CustomStruct.foo[0]",
 532             toString(Root.getError()));
 533   const char *ExpectedDump = R"({
 534   "foo": [
 535     /* error: expected object */
 536     123,
 537     { ... }
 538   ]
 539 })";
 540   EXPECT_EQ(ExpectedDump, errorContext(J, Root));
 541
 542   CustomStruct V;
 543   EXPECT_FALSE(fromJSON(nullptr, V, Root));
 544   EXPECT_EQ("expected object when parsing CustomStruct",
 545             toString(Root.getError()));
 546
 547   EXPECT_FALSE(fromJSON(Object{}, V, Root));
 548   EXPECT_EQ("missing value at CustomStruct.str", toString(Root.getError()));
 549
 550   EXPECT_FALSE(fromJSON(Object{{"str", 1}}, V, Root));
 551   EXPECT_EQ("expected string at CustomStruct.str", toString(Root.getError()));
 552
 553   // std::optional<T> must parse as the correct type if present.
 554   EXPECT_FALSE(fromJSON(Object{{"str", "1"}, {"int", "string"}}, V, Root));
 555   EXPECT_EQ("expected integer at CustomStruct.int", toString(Root.getError()));
 556
 557   // mapOptional must parse as the correct type if present.
 558   EXPECT_FALSE(fromJSON(Object{{"str", "1"}, {"bool", "string"}}, V, Root));
 559   EXPECT_EQ("expected boolean at CustomStruct.bool", toString(Root.getError()));
 560 }
 561
 562 TEST(JSONTest, ParseDeserialize) {
 563   auto E = parse<std::vector<CustomStruct>>(R"json(
 564     [{"str": "foo", "int": 42}, {"int": 42}]
 565   )json");
 566   EXPECT_THAT_EXPECTED(E, FailedWithMessage("missing value at (root)[1].str"));
 567
 568   E = parse<std::vector<CustomStruct>>(R"json(
 569     [{"str": "foo", "int": 42}, {"str": "bar"}
 570   )json");
 571   EXPECT_THAT_EXPECTED(
 572       E,
 573       FailedWithMessage("[3:2, byte=50]: Expected , or ] after array element"));
 574
 575   E = parse<std::vector<CustomStruct>>(R"json(
 576     [{"str": "foo", "int": 42}]
 577   )json");
 578   EXPECT_THAT_EXPECTED(E, Succeeded());
 579   EXPECT_THAT(*E, testing::SizeIs(1));
 580 }
 581
 582 TEST(JSONTest, Stream) {
 583   auto StreamStuff = [](unsigned Indent) {
 584     std::string S;
 585     llvm::raw_string_ostream OS(S);
 586     OStream J(OS, Indent);
 587     J.comment("top*/level");
 588     J.object([&] {
 589       J.attributeArray("foo", [&] {
 590         J.value(nullptr);
 591         J.comment("element");
 592         J.value(42.5);
 593         J.arrayBegin();
 594         J.value(43);
 595         J.arrayEnd();
 596         J.rawValue([](raw_ostream &OS) { OS << "'unverified\nraw value'"; });
 597       });
 598       J.comment("attribute");
 599       J.attributeBegin("bar");
 600       J.comment("attribute value");
 601       J.objectBegin();
 602       J.objectEnd();
 603       J.attributeEnd();
 604       J.attribute("baz", "xyz");
 605     });
 606     return OS.str();
 607   };
 608
 609   const char *Plain =
 610       R"(/*top* /level*/{"foo":[null,/*element*/42.5,[43],'unverified
 611 raw value'],/*attribute*/"bar":/*attribute value*/{},"baz":"xyz"})";
 612   EXPECT_EQ(Plain, StreamStuff(0));
 613   const char *Pretty = R"(/* top* /level */
 614 {
 615   "foo": [
 616     null,
 617     /* element */
 618     42.5,
 619     [
 620       43
 621     ],
 622     'unverified
 623 raw value'
 624   ],
 625   /* attribute */
 626   "bar": /* attribute value */ {},
 627   "baz": "xyz"
 628 })";
 629   EXPECT_EQ(Pretty, StreamStuff(2));
 630 }
 631
 632 TEST(JSONTest, Path) {
 633   Path::Root R("foo");
 634   Path P = R, A = P.field("a"), B = P.field("b");
 635   P.report("oh no");
 636   EXPECT_THAT_ERROR(R.getError(), FailedWithMessage("oh no when parsing foo"));
 637   A.index(1).field("c").index(2).report("boom");
 638   EXPECT_THAT_ERROR(R.getError(), FailedWithMessage("boom at foo.a[1].c[2]"));
 639   B.field("d").field("e").report("bam");
 640   EXPECT_THAT_ERROR(R.getError(), FailedWithMessage("bam at foo.b.d.e"));
 641
 642   Value V = Object{
 643       {"a", Array{42}},
 644       {"b",
 645        Object{{"d",
 646                Object{
 647                    {"e", Array{1, Object{{"x", "y"}}}},
 648                    {"f", "a moderately long string: 48 characters in total"},
 649                }}}},
 650   };
 651   const char *Expected = R"({
 652   "a": [ ... ],
 653   "b": {
 654     "d": {
 655       "e": /* error: bam */ [
 656         1,
 657         { ... }
 658       ],
 659       "f": "a moderately long string: 48 characte..."
 660     }
 661   }
 662 })";
 663   EXPECT_EQ(Expected, errorContext(V, R));
 664 }
 665
 666 } // namespace
 667 } // namespace json
 668 } // namespace llvm