Lady’s Gitweb - Pisces/blob - string.test.js

   1 // ♓🌟 Piscēs ∷ string.test.js
   2 // ====================================================================
   3 //
   4 // Copyright © 2022–2023 Lady [@ Lady’s Computer].
   5 //
   6 // This Source Code Form is subject to the terms of the Mozilla Public
   7 // License, v. 2.0. If a copy of the MPL was not distributed with this
   8 // file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
   9
  10 import {
  11   assert,
  12   assertEquals,
  13   assertSpyCalls,
  14   assertStrictEquals,
  15   assertThrows,
  16   describe,
  17   it,
  18   spy,
  19 } from "./dev-deps.js";
  20 import {
  21   asciiLowercase,
  22   asciiUppercase,
  23   characters,
  24   codepoints,
  25   codeUnits,
  26   getCharacter,
  27   getCodepoint,
  28   getCodeUnit,
  29   getFirstSubstringIndex,
  30   getLastSubstringIndex,
  31   join,
  32   Matcher,
  33   rawString,
  34   scalarValues,
  35   splitOnAsciiWhitespace,
  36   splitOnCommas,
  37   stringCatenate,
  38   stringEndsWith,
  39   stringFromCodepoints,
  40   stringFromCodeUnits,
  41   stringIncludes,
  42   stringMatch,
  43   stringMatchAll,
  44   stringNormalize,
  45   stringPadEnd,
  46   stringPadStart,
  47   stringRepeat,
  48   stringReplace,
  49   stringReplaceAll,
  50   stringSearch,
  51   stringSlice,
  52   stringSplit,
  53   stringStartsWith,
  54   stringValue,
  55   stripAndCollapseAsciiWhitespace,
  56   stripLeadingAndTrailingAsciiWhitespace,
  57   substring,
  58   toScalarValueString,
  59   toString,
  60 } from "./string.js";
  61
  62 describe("Matcher", () => {
  63   it("[[Call]] throws an error", () => {
  64     assertThrows(() => Matcher(""));
  65   });
  66
  67   it("[[Construct]] accepts a string first argument", () => {
  68     assert(new Matcher(""));
  69   });
  70
  71   it("[[Construct]] accepts a unicode regular expression first argument", () => {
  72     assert(new Matcher(/(?:)/u));
  73   });
  74
  75   it("[[Construct]] throws with a non·unicode regular expression first argument", () => {
  76     assertThrows(() => new Matcher(/(?:)/));
  77   });
  78
  79   it("[[Construct]] creates a callable object", () => {
  80     assertStrictEquals(typeof new Matcher(""), "function");
  81   });
  82
  83   it("[[Construct]] creates a new Matcher", () => {
  84     assertStrictEquals(
  85       Object.getPrototypeOf(new Matcher("")),
  86       Matcher.prototype,
  87     );
  88   });
  89
  90   it("[[Construct]] creates an object which inherits from RegExp", () => {
  91     assert(new Matcher("") instanceof RegExp);
  92   });
  93
  94   it("[[Construct]] throws when provided with a noncallable, non·null third argument", () => {
  95     assertThrows(() => new Matcher("", undefined, "failure"));
  96   });
  97
  98   describe(".length", () => {
  99     it("[[Get]] returns the correct length", () => {
 100       assertStrictEquals(Matcher.length, 1);
 101     });
 102   });
 103
 104   describe(".name", () => {
 105     it("[[Get]] returns the correct name", () => {
 106       assertStrictEquals(Matcher.name, "Matcher");
 107     });
 108   });
 109
 110   describe("::dotAll", () => {
 111     it("[[Get]] returns true when the dotAll flag is present", () => {
 112       assertStrictEquals(new Matcher(/(?:)/su).dotAll, true);
 113     });
 114
 115     it("[[Get]] returns false when the dotAll flag is not present", () => {
 116       assertStrictEquals(new Matcher(/(?:)/u).dotAll, false);
 117     });
 118
 119     describe(".length", () => {
 120       it("[[Get]] returns the correct length", () => {
 121         assertStrictEquals(
 122           Object.getOwnPropertyDescriptor(
 123             Matcher.prototype,
 124             "dotAll",
 125           ).get.length,
 126           0,
 127         );
 128       });
 129     });
 130
 131     describe(".name", () => {
 132       it("[[Get]] returns the correct name", () => {
 133         assertStrictEquals(
 134           Object.getOwnPropertyDescriptor(
 135             Matcher.prototype,
 136             "dotAll",
 137           ).get.name,
 138           "get dotAll",
 139         );
 140       });
 141     });
 142   });
 143
 144   describe("::exec", () => {
 145     it("[[Call]] returns the match object given a complete match", () => {
 146       assertEquals(
 147         [...new Matcher(/.(?<wow>(?:.(?=.))*)(.)?/u).exec("success")],
 148         ["success", "ucces", "s"],
 149       );
 150       assertEquals(
 151         [...new Matcher(
 152           /.(?<wow>(?:.(?=.))*)(.)?/u,
 153           undefined,
 154           ($) => $ === "success",
 155         ).exec("success")],
 156         ["success", "ucces", "s"],
 157       );
 158     });
 159
 160     it("[[Call]] calls the constraint if the match succeeds", () => {
 161       const constraint = spy((_) => true);
 162       const matcher = new Matcher("(.).*", undefined, constraint);
 163       const result = matcher.exec({
 164         toString() {
 165           return "etaoin";
 166         },
 167       });
 168       assertEquals([...result], ["etaoin", "e"]);
 169       assertSpyCalls(constraint, 1);
 170       assertStrictEquals(constraint.calls[0].args[0], "etaoin");
 171       assertEquals([...constraint.calls[0].args[1]], ["etaoin", "e"]);
 172       assertStrictEquals(constraint.calls[0].args[2], matcher);
 173       assertStrictEquals(constraint.calls[0].self, undefined);
 174     });
 175
 176     it("[[Call]] does not call the constraint if the match fails", () => {
 177       const constraint = spy((_) => true);
 178       const matcher = new Matcher("", undefined, constraint);
 179       matcher.exec("failure");
 180       assertSpyCalls(constraint, 0);
 181     });
 182
 183     it("[[Call]] returns null given a partial match", () => {
 184       assertStrictEquals(new Matcher("").exec("failure"), null);
 185     });
 186
 187     it("[[Call]] returns null if the constraint fails", () => {
 188       assertStrictEquals(
 189         new Matcher(".*", undefined, () => false).exec(""),
 190         null,
 191       );
 192     });
 193
 194     describe(".length", () => {
 195       it("[[Get]] returns the correct length", () => {
 196         assertStrictEquals(Matcher.prototype.exec.length, 1);
 197       });
 198     });
 199
 200     describe(".name", () => {
 201       it("[[Get]] returns the correct name", () => {
 202         assertStrictEquals(Matcher.prototype.exec.name, "exec");
 203       });
 204     });
 205   });
 206
 207   describe("::global", () => {
 208     it("[[Get]] returns true when the global flag is present", () => {
 209       assertStrictEquals(new Matcher(/(?:)/gu).global, true);
 210     });
 211
 212     it("[[Get]] returns false when the global flag is not present", () => {
 213       assertStrictEquals(new Matcher(/(?:)/u).global, false);
 214     });
 215
 216     describe(".length", () => {
 217       it("[[Get]] returns the correct length", () => {
 218         assertStrictEquals(
 219           Object.getOwnPropertyDescriptor(
 220             Matcher.prototype,
 221             "global",
 222           ).get.length,
 223           0,
 224         );
 225       });
 226     });
 227
 228     describe(".name", () => {
 229       it("[[Get]] returns the correct name", () => {
 230         assertStrictEquals(
 231           Object.getOwnPropertyDescriptor(
 232             Matcher.prototype,
 233             "global",
 234           ).get.name,
 235           "get global",
 236         );
 237       });
 238     });
 239   });
 240
 241   describe("::hasIndices", () => {
 242     it("[[Get]] returns true when the hasIndices flag is present", () => {
 243       assertStrictEquals(new Matcher(/(?:)/du).hasIndices, true);
 244     });
 245
 246     it("[[Get]] returns false when the hasIndices flag is not present", () => {
 247       assertStrictEquals(new Matcher(/(?:)/u).hasIndices, false);
 248     });
 249
 250     describe(".length", () => {
 251       it("[[Get]] returns the correct length", () => {
 252         assertStrictEquals(
 253           Object.getOwnPropertyDescriptor(
 254             Matcher.prototype,
 255             "hasIndices",
 256           ).get.length,
 257           0,
 258         );
 259       });
 260     });
 261
 262     describe(".name", () => {
 263       it("[[Get]] returns the correct name", () => {
 264         assertStrictEquals(
 265           Object.getOwnPropertyDescriptor(
 266             Matcher.prototype,
 267             "hasIndices",
 268           ).get.name,
 269           "get hasIndices",
 270         );
 271       });
 272     });
 273   });
 274
 275   describe("::ignoreCase", () => {
 276     it("[[Get]] returns true when the ignoreCase flag is present", () => {
 277       assertStrictEquals(new Matcher(/(?:)/iu).ignoreCase, true);
 278     });
 279
 280     it("[[Get]] returns false when the ignoreCase flag is not present", () => {
 281       assertStrictEquals(new Matcher(/(?:)/u).ignoreCase, false);
 282     });
 283
 284     describe(".length", () => {
 285       it("[[Get]] returns the correct length", () => {
 286         assertStrictEquals(
 287           Object.getOwnPropertyDescriptor(
 288             Matcher.prototype,
 289             "ignoreCase",
 290           ).get.length,
 291           0,
 292         );
 293       });
 294     });
 295
 296     describe(".name", () => {
 297       it("[[Get]] returns the correct name", () => {
 298         assertStrictEquals(
 299           Object.getOwnPropertyDescriptor(
 300             Matcher.prototype,
 301             "ignoreCase",
 302           ).get.name,
 303           "get ignoreCase",
 304         );
 305       });
 306     });
 307   });
 308
 309   describe("::multiline", () => {
 310     it("[[Get]] returns true when the multiline flag is present", () => {
 311       assertStrictEquals(new Matcher(/(?:)/mu).multiline, true);
 312     });
 313
 314     it("[[Get]] returns false when the multiline flag is not present", () => {
 315       assertStrictEquals(new Matcher(/(?:)/u).multiline, false);
 316     });
 317
 318     describe(".length", () => {
 319       it("[[Get]] returns the correct length", () => {
 320         assertStrictEquals(
 321           Object.getOwnPropertyDescriptor(
 322             Matcher.prototype,
 323             "multiline",
 324           ).get.length,
 325           0,
 326         );
 327       });
 328     });
 329
 330     describe(".name", () => {
 331       it("[[Get]] returns the correct name", () => {
 332         assertStrictEquals(
 333           Object.getOwnPropertyDescriptor(
 334             Matcher.prototype,
 335             "multiline",
 336           ).get.name,
 337           "get multiline",
 338         );
 339       });
 340     });
 341   });
 342
 343   describe("::source", () => {
 344     it("[[Get]] returns the RegExp source", () => {
 345       assertStrictEquals(new Matcher("").source, "(?:)");
 346       assertStrictEquals(new Matcher(/.*/su).source, ".*");
 347     });
 348
 349     describe(".length", () => {
 350       it("[[Get]] returns the correct length", () => {
 351         assertStrictEquals(
 352           Object.getOwnPropertyDescriptor(
 353             Matcher.prototype,
 354             "source",
 355           ).get.length,
 356           0,
 357         );
 358       });
 359     });
 360
 361     describe(".name", () => {
 362       it("[[Get]] returns the correct name", () => {
 363         assertStrictEquals(
 364           Object.getOwnPropertyDescriptor(
 365             Matcher.prototype,
 366             "source",
 367           ).get.name,
 368           "get source",
 369         );
 370       });
 371     });
 372   });
 373
 374   describe("::sticky", () => {
 375     it("[[Get]] returns true when the sticky flag is present", () => {
 376       assertStrictEquals(new Matcher(/(?:)/uy).sticky, true);
 377     });
 378
 379     it("[[Get]] returns false when the sticky flag is not present", () => {
 380       assertStrictEquals(new Matcher(/(?:)/u).sticky, false);
 381     });
 382
 383     describe(".length", () => {
 384       it("[[Get]] returns the correct length", () => {
 385         assertStrictEquals(
 386           Object.getOwnPropertyDescriptor(
 387             Matcher.prototype,
 388             "sticky",
 389           ).get.length,
 390           0,
 391         );
 392       });
 393     });
 394
 395     describe(".name", () => {
 396       it("[[Get]] returns the correct name", () => {
 397         assertStrictEquals(
 398           Object.getOwnPropertyDescriptor(
 399             Matcher.prototype,
 400             "sticky",
 401           ).get.name,
 402           "get sticky",
 403         );
 404       });
 405     });
 406   });
 407
 408   describe("::toString", () => {
 409     it("[[Call]] returns the string source", () => {
 410       assertStrictEquals(new Matcher(/(?:)/u).toString(), "/(?:)/u");
 411     });
 412   });
 413
 414   describe("::unicode", () => {
 415     it("[[Get]] returns true when the unicode flag is present", () => {
 416       assertStrictEquals(new Matcher(/(?:)/u).unicode, true);
 417     });
 418
 419     describe(".length", () => {
 420       it("[[Get]] returns the correct length", () => {
 421         assertStrictEquals(
 422           Object.getOwnPropertyDescriptor(
 423             Matcher.prototype,
 424             "unicode",
 425           ).get.length,
 426           0,
 427         );
 428       });
 429     });
 430
 431     describe(".name", () => {
 432       it("[[Get]] returns the correct name", () => {
 433         assertStrictEquals(
 434           Object.getOwnPropertyDescriptor(
 435             Matcher.prototype,
 436             "unicode",
 437           ).get.name,
 438           "get unicode",
 439         );
 440       });
 441     });
 442   });
 443
 444   describe("~", () => {
 445     it("[[Call]] returns true for a complete match", () => {
 446       assertStrictEquals(new Matcher("")(""), true);
 447       assertStrictEquals(new Matcher(/.*/su)("success\nyay"), true);
 448       assertStrictEquals(
 449         new Matcher(/.*/su, undefined, ($) => $ === "success")(
 450           "success",
 451         ),
 452         true,
 453       );
 454     });
 455
 456     it("[[Call]] calls the constraint if the match succeeds", () => {
 457       const constraint = spy((_) => true);
 458       const matcher = new Matcher("(.).*", undefined, constraint);
 459       matcher("etaoin");
 460       assertSpyCalls(constraint, 1);
 461       assertStrictEquals(constraint.calls[0].args[0], "etaoin");
 462       assertEquals([...constraint.calls[0].args[1]], ["etaoin", "e"]);
 463       assertStrictEquals(constraint.calls[0].args[2], matcher);
 464       assertStrictEquals(constraint.calls[0].self, undefined);
 465     });
 466
 467     it("[[Call]] does not call the constraint if the match fails", () => {
 468       const constraint = spy((_) => true);
 469       const matcher = new Matcher("", undefined, constraint);
 470       matcher("failure");
 471       assertSpyCalls(constraint, 0);
 472     });
 473
 474     it("[[Call]] returns false for a partial match", () => {
 475       assertStrictEquals(new Matcher("")("failure"), false);
 476       assertStrictEquals(new Matcher(/.*/u)("failure\nno"), false);
 477     });
 478
 479     it("[[Call]] returns false if the constraint fails", () => {
 480       assertStrictEquals(
 481         new Matcher(".*", undefined, () => false)(""),
 482         false,
 483       );
 484     });
 485   });
 486
 487   describe("~lastIndex", () => {
 488     it("[[Get]] returns zero", () => {
 489       assertStrictEquals(new Matcher("").lastIndex, 0);
 490     });
 491
 492     it("[[Set]] fails", () => {
 493       assertThrows(() => (new Matcher("").lastIndex = 1));
 494     });
 495   });
 496
 497   describe("~length", () => {
 498     it("[[Get]] returns one", () => {
 499       assertStrictEquals(new Matcher("").length, 1);
 500     });
 501   });
 502
 503   describe("~name", () => {
 504     it("[[Get]] wraps the stringified regular expression if no name was provided", () => {
 505       assertStrictEquals(new Matcher("").name, "Matcher(/(?:)/u)");
 506       assertStrictEquals(
 507         new Matcher(/.*/gsu).name,
 508         "Matcher(/.*/gsu)",
 509       );
 510     });
 511
 512     it("[[Get]] uses the provided name if one was provided", () => {
 513       assertStrictEquals(new Matcher("", "success").name, "success");
 514     });
 515   });
 516 });
 517
 518 describe("asciiLowercase", () => {
 519   it("[[Call]] lowercases (just) A·S·C·I·I letters", () => {
 520     assertStrictEquals(asciiLowercase("aBſÆss FtɁɂß"), "abſÆss ftɁɂß");
 521   });
 522
 523   it("[[Construct]] throws an error", () => {
 524     assertThrows(() => new asciiLowercase(""));
 525   });
 526
 527   describe(".length", () => {
 528     it("[[Get]] returns the correct length", () => {
 529       assertStrictEquals(asciiLowercase.length, 1);
 530     });
 531   });
 532
 533   describe(".name", () => {
 534     it("[[Get]] returns the correct name", () => {
 535       assertStrictEquals(asciiLowercase.name, "asciiLowercase");
 536     });
 537   });
 538 });
 539
 540 describe("asciiUppercase", () => {
 541   it("[[Call]] uppercases (just) A·S·C·I·I letters", () => {
 542     assertStrictEquals(asciiUppercase("aBſÆss FtɁɂß"), "ABſÆSS FTɁɂß");
 543   });
 544
 545   it("[[Construct]] throws an error", () => {
 546     assertThrows(() => new asciiUppercase(""));
 547   });
 548
 549   describe(".length", () => {
 550     it("[[Get]] returns the correct length", () => {
 551       assertStrictEquals(asciiUppercase.length, 1);
 552     });
 553   });
 554
 555   describe(".name", () => {
 556     it("[[Get]] returns the correct name", () => {
 557       assertStrictEquals(asciiUppercase.name, "asciiUppercase");
 558     });
 559   });
 560 });
 561
 562 describe("characters", () => {
 563   it("[[Call]] returns an iterable", () => {
 564     assertStrictEquals(
 565       typeof characters("")[Symbol.iterator],
 566       "function",
 567     );
 568   });
 569
 570   it("[[Call]] returns an iterator", () => {
 571     assertStrictEquals(typeof characters("").next, "function");
 572   });
 573
 574   it("[[Call]] returns a string character iterator", () => {
 575     assertStrictEquals(
 576       characters("")[Symbol.toStringTag],
 577       "String Character Iterator",
 578     );
 579   });
 580
 581   it("[[Call]] iterates over the characters", () => {
 582     assertEquals([
 583       ...characters("Ii🎙\uDFFF\uDD96\uD83C\uD800🆗☺"),
 584     ], [
 585       "I",
 586       "i",
 587       "🎙",
 588       "\uDFFF",
 589       "\uDD96",
 590       "\uD83C",
 591       "\uD800",
 592       "🆗",
 593       "☺",
 594     ]);
 595   });
 596
 597   it("[[Construct]] throws an error", () => {
 598     assertThrows(() => new characters(""));
 599   });
 600
 601   describe(".length", () => {
 602     it("[[Get]] returns the correct length", () => {
 603       assertStrictEquals(characters.length, 1);
 604     });
 605   });
 606
 607   describe(".name", () => {
 608     it("[[Get]] returns the correct name", () => {
 609       assertStrictEquals(characters.name, "characters");
 610     });
 611   });
 612 });
 613
 614 describe("codeUnits", () => {
 615   it("[[Call]] returns an iterable", () => {
 616     assertStrictEquals(
 617       typeof codeUnits("")[Symbol.iterator],
 618       "function",
 619     );
 620   });
 621
 622   it("[[Call]] returns an iterator", () => {
 623     assertStrictEquals(typeof codeUnits("").next, "function");
 624   });
 625
 626   it("[[Call]] returns a string code unit iterator", () => {
 627     assertStrictEquals(
 628       codeUnits("")[Symbol.toStringTag],
 629       "String Code Unit Iterator",
 630     );
 631   });
 632
 633   it("[[Call]] iterates over the code units", () => {
 634     assertEquals([
 635       ...codeUnits("Ii🎙\uDFFF\uDD96\uD83C\uD800🆗☺"),
 636     ], [
 637       0x49,
 638       0x69,
 639       0xD83C,
 640       0xDF99,
 641       0xDFFF,
 642       0xDD96,
 643       0xD83C,
 644       0xD800,
 645       0xD83C,
 646       0xDD97,
 647       0x263A,
 648     ]);
 649   });
 650
 651   it("[[Construct]] throws an error", () => {
 652     assertThrows(() => new codeUnits(""));
 653   });
 654
 655   describe(".length", () => {
 656     it("[[Get]] returns the correct length", () => {
 657       assertStrictEquals(codeUnits.length, 1);
 658     });
 659   });
 660
 661   describe(".name", () => {
 662     it("[[Get]] returns the correct name", () => {
 663       assertStrictEquals(codeUnits.name, "codeUnits");
 664     });
 665   });
 666 });
 667
 668 describe("codepoints", () => {
 669   it("[[Call]] returns an iterable", () => {
 670     assertStrictEquals(
 671       typeof codepoints("")[Symbol.iterator],
 672       "function",
 673     );
 674   });
 675
 676   it("[[Call]] returns an iterator", () => {
 677     assertStrictEquals(typeof codepoints("").next, "function");
 678   });
 679
 680   it("[[Call]] returns a string codepoint iterator", () => {
 681     assertStrictEquals(
 682       codepoints("")[Symbol.toStringTag],
 683       "String Codepoint Iterator",
 684     );
 685   });
 686
 687   it("[[Call]] iterates over the codepoints", () => {
 688     assertEquals([
 689       ...codepoints("Ii🎙\uDFFF\uDD96\uD83C\uD800🆗☺"),
 690     ], [
 691       0x49,
 692       0x69,
 693       0x1F399,
 694       0xDFFF,
 695       0xDD96,
 696       0xD83C,
 697       0xD800,
 698       0x1F197,
 699       0x263A,
 700     ]);
 701   });
 702
 703   it("[[Construct]] throws an error", () => {
 704     assertThrows(() => new codepoints(""));
 705   });
 706
 707   describe(".length", () => {
 708     it("[[Get]] returns the correct length", () => {
 709       assertStrictEquals(codepoints.length, 1);
 710     });
 711   });
 712
 713   describe(".name", () => {
 714     it("[[Get]] returns the correct name", () => {
 715       assertStrictEquals(codepoints.name, "codepoints");
 716     });
 717   });
 718 });
 719
 720 describe("getCharacter", () => {
 721   it("[[Call]] returns the character at the provided position", () => {
 722     assertStrictEquals(getCharacter("Ii🎙🆗☺", 4), "🆗");
 723   });
 724
 725   it("[[Call]] returns a low surrogate if the provided position splits a character", () => {
 726     assertStrictEquals(getCharacter("Ii🎙🆗☺", 5), "\uDD97");
 727   });
 728
 729   it("[[Call]] returns undefined for an out‐of‐bounds index", () => {
 730     assertStrictEquals(getCharacter("Ii🎙🆗☺", -1), undefined);
 731     assertStrictEquals(getCharacter("Ii🎙🆗☺", 7), undefined);
 732   });
 733
 734   it("[[Construct]] throws an error", () => {
 735     assertThrows(() => new getCharacter("a", 0));
 736   });
 737
 738   describe(".length", () => {
 739     it("[[Get]] returns the correct length", () => {
 740       assertStrictEquals(getCharacter.length, 2);
 741     });
 742   });
 743
 744   describe(".name", () => {
 745     it("[[Get]] returns the correct name", () => {
 746       assertStrictEquals(getCharacter.name, "getCharacter");
 747     });
 748   });
 749 });
 750
 751 describe("getCodeUnit", () => {
 752   it("[[Call]] returns the code unit at the provided position", () => {
 753     assertStrictEquals(getCodeUnit("Ii🎙🆗☺", 4), 0xD83C);
 754   });
 755
 756   it("[[Call]] returns a low surrogate if the provided position splits a character", () => {
 757     assertStrictEquals(getCodeUnit("Ii🎙🆗☺", 5), 0xDD97);
 758   });
 759
 760   it("[[Call]] returns undefined for an out‐of‐bounds index", () => {
 761     assertStrictEquals(getCodeUnit("Ii🎙🆗☺", -1), undefined);
 762     assertStrictEquals(getCodeUnit("Ii🎙🆗☺", 7), undefined);
 763   });
 764
 765   it("[[Construct]] throws an error", () => {
 766     assertThrows(() => new getCodeUnit("a", 0));
 767   });
 768
 769   describe(".length", () => {
 770     it("[[Get]] returns the correct length", () => {
 771       assertStrictEquals(getCodeUnit.length, 2);
 772     });
 773   });
 774
 775   describe(".name", () => {
 776     it("[[Get]] returns the correct name", () => {
 777       assertStrictEquals(getCodeUnit.name, "getCodeUnit");
 778     });
 779   });
 780 });
 781
 782 describe("getCodepoint", () => {
 783   it("[[Call]] returns the character at the provided position", () => {
 784     assertStrictEquals(getCodepoint("Ii🎙🆗☺", 4), 0x1F197);
 785   });
 786
 787   it("[[Call]] returns a low surrogate if the provided position splits a character", () => {
 788     assertStrictEquals(getCodepoint("Ii🎙🆗☺", 5), 0xDD97);
 789   });
 790
 791   it("[[Call]] returns undefined for an out‐of‐bounds index", () => {
 792     assertStrictEquals(getCodepoint("Ii🎙🆗☺", -1), undefined);
 793     assertStrictEquals(getCodepoint("Ii🎙🆗☺", 7), undefined);
 794   });
 795
 796   it("[[Construct]] throws an error", () => {
 797     assertThrows(() => new getCodepoint("a", 0));
 798   });
 799
 800   describe(".length", () => {
 801     it("[[Get]] returns the correct length", () => {
 802       assertStrictEquals(getCodepoint.length, 2);
 803     });
 804   });
 805
 806   describe(".name", () => {
 807     it("[[Get]] returns the correct name", () => {
 808       assertStrictEquals(getCodepoint.name, "getCodepoint");
 809     });
 810   });
 811 });
 812
 813 describe("getFirstSubstringIndex", () => {
 814   it("[[Call]] returns the index of the first match", () => {
 815     assertStrictEquals(getFirstSubstringIndex("Ii🎙🆗☺🆗", "🆗"), 4);
 816   });
 817
 818   it("[[Call]] returns −1 if no match is found", () => {
 819     assertStrictEquals(getFirstSubstringIndex("Ii🎙🆗☺🆗", "🆗🆖"), -1);
 820   });
 821
 822   it("[[Call]] returns 0 when provided with an empty string", () => {
 823     assertStrictEquals(getFirstSubstringIndex("Ii🎙🆗☺🆗", ""), 0);
 824   });
 825
 826   it("[[Construct]] throws an error", () => {
 827     assertThrows(() => new getFirstSubstringIndex("", ""));
 828   });
 829
 830   describe(".length", () => {
 831     it("[[Get]] returns the correct length", () => {
 832       assertStrictEquals(getFirstSubstringIndex.length, 2);
 833     });
 834   });
 835
 836   describe(".name", () => {
 837     it("[[Get]] returns the correct name", () => {
 838       assertStrictEquals(
 839         getFirstSubstringIndex.name,
 840         "getFirstSubstringIndex",
 841       );
 842     });
 843   });
 844 });
 845
 846 describe("getLastSubstringIndex", () => {
 847   it("[[Call]] returns the index of the first match", () => {
 848     assertStrictEquals(getLastSubstringIndex("Ii🎙🆗☺🆗", "🆗"), 7);
 849   });
 850
 851   it("[[Call]] returns −1 if no match is found", () => {
 852     assertStrictEquals(getLastSubstringIndex("Ii🎙🆗☺🆗", "🆖🆗"), -1);
 853   });
 854
 855   it("[[Call]] returns the length when provided with an empty string", () => {
 856     assertStrictEquals(
 857       getLastSubstringIndex("Ii🎙🆗☺🆗", ""),
 858       "Ii🎙🆗☺🆗".length,
 859     );
 860   });
 861
 862   it("[[Construct]] throws an error", () => {
 863     assertThrows(() => new getLastSubstringIndex("", ""));
 864   });
 865
 866   describe(".length", () => {
 867     it("[[Get]] returns the correct length", () => {
 868       assertStrictEquals(getLastSubstringIndex.length, 2);
 869     });
 870   });
 871
 872   describe(".name", () => {
 873     it("[[Get]] returns the correct name", () => {
 874       assertStrictEquals(
 875         getLastSubstringIndex.name,
 876         "getLastSubstringIndex",
 877       );
 878     });
 879   });
 880 });
 881
 882 describe("join", () => {
 883   it("[[Call]] joins the provided iterator with the provided separartor", () => {
 884     assertStrictEquals(join([1, 2, 3, 4].values(), "☂"), "1☂2☂3☂4");
 885   });
 886
 887   it('[[Call]] uses "," if no separator is provided', () => {
 888     assertStrictEquals(join([1, 2, 3, 4].values()), "1,2,3,4");
 889   });
 890
 891   it("[[Call]] uses the empty sting for nullish values", () => {
 892     assertStrictEquals(
 893       join([null, , null, undefined].values(), "☂"),
 894       "☂☂☂",
 895     );
 896   });
 897
 898   it("[[Construct]] throws an error", () => {
 899     assertThrows(() => new join([]));
 900   });
 901
 902   describe(".length", () => {
 903     it("[[Get]] returns the correct length", () => {
 904       assertStrictEquals(join.length, 2);
 905     });
 906   });
 907
 908   describe(".name", () => {
 909     it("[[Get]] returns the correct name", () => {
 910       assertStrictEquals(join.name, "join");
 911     });
 912   });
 913 });
 914
 915 describe("rawString", () => {
 916   it("[[Call]] acts like String.raw", () => {
 917     assertStrictEquals(rawString`\nraw${" string"}`, "\\nraw string");
 918   });
 919
 920   it("[[Construct]] throws an error", () => {
 921     assertThrows(() => new rawString(["string"]));
 922   });
 923
 924   describe(".length", () => {
 925     it("[[Get]] returns the correct length", () => {
 926       assertStrictEquals(rawString.length, 1);
 927     });
 928   });
 929
 930   describe(".name", () => {
 931     it("[[Get]] returns the correct name", () => {
 932       assertStrictEquals(rawString.name, "rawString");
 933     });
 934   });
 935 });
 936
 937 describe("scalarValues", () => {
 938   it("[[Call]] returns an iterable", () => {
 939     assertStrictEquals(
 940       typeof scalarValues("")[Symbol.iterator],
 941       "function",
 942     );
 943   });
 944
 945   it("[[Call]] returns an iterator", () => {
 946     assertStrictEquals(typeof scalarValues("").next, "function");
 947   });
 948
 949   it("[[Call]] returns a string scalar value iterator", () => {
 950     assertStrictEquals(
 951       scalarValues("")[Symbol.toStringTag],
 952       "String Scalar Value Iterator",
 953     );
 954   });
 955
 956   it("[[Call]] iterates over the scalar values", () => {
 957     assertEquals([
 958       ...scalarValues("Ii🎙\uDFFF\uDD96\uD83C\uD800🆗☺"),
 959     ], [
 960       0x49,
 961       0x69,
 962       0x1F399,
 963       0xFFFD,
 964       0xFFFD,
 965       0xFFFD,
 966       0xFFFD,
 967       0x1F197,
 968       0x263A,
 969     ]);
 970   });
 971
 972   it("[[Construct]] throws an error", () => {
 973     assertThrows(() => new scalarValues(""));
 974   });
 975
 976   describe(".length", () => {
 977     it("[[Get]] returns the correct length", () => {
 978       assertStrictEquals(scalarValues.length, 1);
 979     });
 980   });
 981
 982   describe(".name", () => {
 983     it("[[Get]] returns the correct name", () => {
 984       assertStrictEquals(scalarValues.name, "scalarValues");
 985     });
 986   });
 987 });
 988
 989 describe("splitOnAsciiWhitespace", () => {
 990   it("[[Call]] splits on sequences of spaces", () => {
 991     assertEquals(
 992       splitOnAsciiWhitespace("🅰️   🅱️ 🆎  🅾️"),
 993       ["🅰️", "🅱️", "🆎", "🅾️"],
 994     );
 995   });
 996
 997   it("[[Call]] splits on sequences of tabs", () => {
 998     assertEquals(
 999       splitOnAsciiWhitespace("🅰️\t\t\t🅱️\t🆎\t\t🅾️"),
1000       ["🅰️", "🅱️", "🆎", "🅾️"],
1001     );
1002   });
1003
1004   it("[[Call]] splits on sequences of carriage returns", () => {
1005     assertEquals(
1006       splitOnAsciiWhitespace("🅰️\r\r\r🅱️\r🆎\r\r🅾️"),
1007       ["🅰️", "🅱️", "🆎", "🅾️"],
1008     );
1009   });
1010
1011   it("[[Call]] splits on sequences of newlines", () => {
1012     assertEquals(
1013       splitOnAsciiWhitespace("🅰️\r\r\r🅱️\r🆎\r\r🅾️"),
1014       ["🅰️", "🅱️", "🆎", "🅾️"],
1015     );
1016   });
1017
1018   it("[[Call]] splits on sequences of form feeds", () => {
1019     assertEquals(
1020       splitOnAsciiWhitespace("🅰️\f\f\f🅱️\f🆎\f\f🅾️"),
1021       ["🅰️", "🅱️", "🆎", "🅾️"],
1022     );
1023   });
1024
1025   it("[[Call]] splits on mixed whitespace", () => {
1026     assertEquals(
1027       splitOnAsciiWhitespace("🅰️\f \t\n🅱️\r\n\r🆎\n\f🅾️"),
1028       ["🅰️", "🅱️", "🆎", "🅾️"],
1029     );
1030   });
1031
1032   it("[[Call]] returns an array of just the empty string for the empty string", () => {
1033     assertEquals(splitOnAsciiWhitespace(""), [""]);
1034   });
1035
1036   it("[[Call]] returns a single token if there are no spaces", () => {
1037     assertEquals(splitOnAsciiWhitespace("abcd"), ["abcd"]);
1038   });
1039
1040   it("[[Call]] does not split on other kinds of whitespace", () => {
1041     assertEquals(
1042       splitOnAsciiWhitespace("a\u202F\u205F\xa0\v\0\bb"),
1043       ["a\u202F\u205F\xa0\v\0\bb"],
1044     );
1045   });
1046
1047   it("[[Call]] trims leading and trailing whitespace", () => {
1048     assertEquals(
1049       splitOnAsciiWhitespace(
1050         "\f\r\n\r\n \n\t🅰️\f \t\n🅱️\r🆎\n\f🅾️\n\f",
1051       ),
1052       ["🅰️", "🅱️", "🆎", "🅾️"],
1053     );
1054   });
1055
1056   it("[[Construct]] throws an error", () => {
1057     assertThrows(() => new splitOnAsciiWhitespace(""));
1058   });
1059
1060   describe(".length", () => {
1061     it("[[Get]] returns the correct length", () => {
1062       assertStrictEquals(splitOnAsciiWhitespace.length, 1);
1063     });
1064   });
1065
1066   describe(".name", () => {
1067     it("[[Get]] returns the correct name", () => {
1068       assertStrictEquals(
1069         splitOnAsciiWhitespace.name,
1070         "splitOnAsciiWhitespace",
1071       );
1072     });
1073   });
1074 });
1075
1076 describe("splitOnCommas", () => {
1077   it("[[Call]] splits on commas", () => {
1078     assertEquals(
1079       splitOnCommas("🅰️,🅱️,🆎,🅾️"),
1080       ["🅰️", "🅱️", "🆎", "🅾️"],
1081     );
1082   });
1083
1084   it("[[Call]] returns an array of just the empty string for the empty string", () => {
1085     assertEquals(splitOnCommas(""), [""]);
1086   });
1087
1088   it("[[Call]] returns a single token if there are no commas", () => {
1089     assertEquals(splitOnCommas("abcd"), ["abcd"]);
1090   });
1091
1092   it("[[Call]] splits into empty strings if there are only commas", () => {
1093     assertEquals(splitOnCommas(",,,"), ["", "", "", ""]);
1094   });
1095
1096   it("[[Call]] trims leading and trailing whitespace", () => {
1097     assertEquals(
1098       splitOnCommas("\f\r\n\r\n \n\t🅰️,🅱️,🆎,🅾️\n\f"),
1099       ["🅰️", "🅱️", "🆎", "🅾️"],
1100     );
1101     assertEquals(
1102       splitOnCommas("\f\r\n\r\n \n\t,,,\n\f"),
1103       ["", "", "", ""],
1104     );
1105   });
1106
1107   it("[[Call]] removes whitespace from the split tokens", () => {
1108     assertEquals(
1109       splitOnCommas(
1110         "\f\r\n\r\n \n\t🅰️\f , \t\n🅱️,\r\n\r🆎\n\f,🅾️\n\f",
1111       ),
1112       ["🅰️", "🅱️", "🆎", "🅾️"],
1113     );
1114     assertEquals(
1115       splitOnCommas("\f\r\n\r\n \n\t\f , \t\n,\r\n\r\n\f,\n\f"),
1116       ["", "", "", ""],
1117     );
1118   });
1119
1120   it("[[Construct]] throws an error", () => {
1121     assertThrows(() => new splitOnCommas(""));
1122   });
1123
1124   describe(".length", () => {
1125     it("[[Get]] returns the correct length", () => {
1126       assertStrictEquals(splitOnCommas.length, 1);
1127     });
1128   });
1129
1130   describe(".name", () => {
1131     it("[[Get]] returns the correct name", () => {
1132       assertStrictEquals(splitOnCommas.name, "splitOnCommas");
1133     });
1134   });
1135 });
1136
1137 describe("stringCatenate", () => {
1138   it("[[Call]] catenates the values", () => {
1139     assertStrictEquals(stringCatenate("the", " values"), "the values");
1140   });
1141
1142   it("[[Call]] returns an empty string when called with no values", () => {
1143     assertStrictEquals(stringCatenate(), "");
1144   });
1145
1146   it('[[Call]] uses "undefined" when explicitly provided undefined', () => {
1147     assertStrictEquals(
1148       stringCatenate(undefined, undefined),
1149       "undefinedundefined",
1150     );
1151   });
1152
1153   it('[[Call]] uses "null" when provided null', () => {
1154     assertStrictEquals(stringCatenate(null, null), "nullnull");
1155   });
1156
1157   it("[[Construct]] throws an error", () => {
1158     assertThrows(() => new stringCatenate());
1159   });
1160
1161   describe(".length", () => {
1162     it("[[Get]] returns the correct length", () => {
1163       assertStrictEquals(stringCatenate.length, 2);
1164     });
1165   });
1166
1167   describe(".name", () => {
1168     it("[[Get]] returns the correct name", () => {
1169       assertStrictEquals(stringCatenate.name, "stringCatenate");
1170     });
1171   });
1172 });
1173
1174 describe("stringEndsWith", () => {
1175   it("[[Call]] returns whether the string ends with the thing", () => {
1176     assertStrictEquals(
1177       stringEndsWith("very success", " success"),
1178       true,
1179     );
1180     assertStrictEquals(stringEndsWith("very fail", " success"), false);
1181   });
1182
1183   it("[[Call]] accepts an offset", () => {
1184     assertStrictEquals(
1185       stringEndsWith("very successful", " success", 12),
1186       true,
1187     );
1188   });
1189
1190   it("[[Call]] returns true for an empty string test", () => {
1191     assertStrictEquals(stringEndsWith("", ""), true);
1192   });
1193
1194   it("[[Construct]] throws an error", () => {
1195     assertThrows(() => new stringEndsWith("", ""));
1196   });
1197
1198   describe(".length", () => {
1199     it("[[Get]] returns the correct length", () => {
1200       assertStrictEquals(stringEndsWith.length, 2);
1201     });
1202   });
1203
1204   describe(".name", () => {
1205     it("[[Get]] returns the correct name", () => {
1206       assertStrictEquals(stringEndsWith.name, "stringEndsWith");
1207     });
1208   });
1209 });
1210
1211 describe("stringFromCodeUnits", () => {
1212   it("[[Call]] makes the string", () => {
1213     assertStrictEquals(
1214       stringFromCodeUnits(0xD83C, 0xDD97),
1215       "🆗",
1216     );
1217   });
1218
1219   it("[[Call]] throws with non‐integral arguments", () => {
1220     assertThrows(() => stringFromCodeUnits(NaN));
1221     assertThrows(() => stringFromCodeUnits(Infinity));
1222     assertThrows(() => stringFromCodeUnits(0.1));
1223   });
1224
1225   it("[[Call]] throws with arguments out of range", () => {
1226     assertThrows(() => stringFromCodeUnits(-1));
1227     assertThrows(() => stringFromCodeUnits(0x10000));
1228   });
1229
1230   it("[[Construct]] throws an error", () => {
1231     assertThrows(() => new stringFromCodeUnits([]));
1232   });
1233
1234   describe(".length", () => {
1235     it("[[Get]] returns the correct length", () => {
1236       assertStrictEquals(stringFromCodeUnits.length, 1);
1237     });
1238   });
1239
1240   describe(".name", () => {
1241     it("[[Get]] returns the correct name", () => {
1242       assertStrictEquals(
1243         stringFromCodeUnits.name,
1244         "stringFromCodeUnits",
1245       );
1246     });
1247   });
1248 });
1249
1250 describe("stringFromCodepoints", () => {
1251   it("[[Call]] makes the string", () => {
1252     assertStrictEquals(stringFromCodepoints(0x1F197), "🆗");
1253   });
1254
1255   it("[[Call]] throws with non‐integral arguments", () => {
1256     assertThrows(() => stringFromCodepoints(NaN));
1257     assertThrows(() => stringFromCodepoints(Infinity));
1258     assertThrows(() => stringFromCodepoints(0.1));
1259   });
1260
1261   it("[[Call]] throws with arguments out of range", () => {
1262     assertThrows(() => stringFromCodepoints(-1));
1263     assertThrows(() => stringFromCodepoints(0x110000));
1264   });
1265
1266   it("[[Construct]] throws an error", () => {
1267     assertThrows(() => new stringFromCodepoints([]));
1268   });
1269
1270   describe(".length", () => {
1271     it("[[Get]] returns the correct length", () => {
1272       assertStrictEquals(stringFromCodepoints.length, 1);
1273     });
1274   });
1275
1276   describe(".name", () => {
1277     it("[[Get]] returns the correct name", () => {
1278       assertStrictEquals(
1279         stringFromCodepoints.name,
1280         "stringFromCodepoints",
1281       );
1282     });
1283   });
1284 });
1285
1286 describe("stringIncludes", () => {
1287   it("[[Call]] returns whether the string includes the thing", () => {
1288     assertStrictEquals(
1289       stringIncludes("very success full", " success "),
1290       true,
1291     );
1292     assertStrictEquals(
1293       stringIncludes("very fail full", " success "),
1294       false,
1295     );
1296   });
1297
1298   it("[[Call]] accepts an offset", () => {
1299     assertStrictEquals(
1300       stringIncludes("maybe success full", " success ", 4),
1301       true,
1302     );
1303     assertStrictEquals(
1304       stringIncludes("maybe success full", " success ", 5),
1305       true,
1306     );
1307     assertStrictEquals(
1308       stringIncludes("maybe success full", " success ", 6),
1309       false,
1310     );
1311   });
1312
1313   it("[[Call]] returns true for an empty string test", () => {
1314     assertStrictEquals(stringIncludes("", ""), true);
1315   });
1316
1317   it("[[Construct]] throws an error", () => {
1318     assertThrows(() => new stringIncludes("", ""));
1319   });
1320
1321   describe(".length", () => {
1322     it("[[Get]] returns the correct length", () => {
1323       assertStrictEquals(stringIncludes.length, 2);
1324     });
1325   });
1326
1327   describe(".name", () => {
1328     it("[[Get]] returns the correct name", () => {
1329       assertStrictEquals(stringIncludes.name, "stringIncludes");
1330     });
1331   });
1332 });
1333
1334 describe("stringMatch", () => {
1335   it("[[Call]] does the match akin to String::match", () => {
1336     assertEquals(
1337       [...stringMatch("very success full", /([sc]+[ue]?)+/)],
1338       ["success", "ss"],
1339     );
1340     assertEquals(
1341       [...stringMatch("very success full", /([sc]+)[ue]?/g)],
1342       ["su", "cce", "ss"],
1343     );
1344   });
1345
1346   it("[[Construct]] throws an error", () => {
1347     assertThrows(() => new stringMatch("", /(?:)/));
1348   });
1349
1350   describe(".length", () => {
1351     it("[[Get]] returns the correct length", () => {
1352       assertStrictEquals(stringMatch.length, 2);
1353     });
1354   });
1355
1356   describe(".name", () => {
1357     it("[[Get]] returns the correct name", () => {
1358       assertStrictEquals(stringMatch.name, "stringMatch");
1359     });
1360   });
1361 });
1362
1363 describe("stringMatchAll", () => {
1364   it("[[Call]] does the match akin to String::matchAll", () => {
1365     assertEquals(
1366       [...stringMatchAll("very success full", /([sc]+)[ue]?/g)].map((
1367         match,
1368       ) => [...match]),
1369       [["su", "s"], ["cce", "cc"], ["ss", "ss"]],
1370     );
1371   });
1372
1373   it("[[Construct]] throws an error", () => {
1374     assertThrows(() => new stringMatchAll("", /(?:)/g));
1375   });
1376
1377   describe(".length", () => {
1378     it("[[Get]] returns the correct length", () => {
1379       assertStrictEquals(stringMatchAll.length, 2);
1380     });
1381   });
1382
1383   describe(".name", () => {
1384     it("[[Get]] returns the correct name", () => {
1385       assertStrictEquals(stringMatchAll.name, "stringMatchAll");
1386     });
1387   });
1388 });
1389
1390 describe("stringNormalize", () => {
1391   it("[[Call]] normalizes the string properly", () => {
1392     assertStrictEquals(stringNormalize("ẛ", "NFC"), "\u1E9B");
1393     assertStrictEquals(stringNormalize("ẛ", "NFD"), "\u017F\u0307");
1394     assertStrictEquals(stringNormalize("ẛ", "NFKC"), "\u1E61");
1395     assertStrictEquals(stringNormalize("ẛ", "NFKD"), "\u0073\u0307");
1396   });
1397
1398   it("[[Call]] assumes NFC", () => {
1399     assertStrictEquals(stringNormalize("\u017F\u0307"), "\u1E9B");
1400   });
1401
1402   it("[[Call]] throws with an invalid form", () => {
1403     assertThrows(() => stringNormalize("", "NFB"));
1404   });
1405
1406   it("[[Construct]] throws an error", () => {
1407     assertThrows(() => new stringNormalize("", "NFC"));
1408   });
1409
1410   describe(".length", () => {
1411     it("[[Get]] returns the correct length", () => {
1412       assertStrictEquals(stringNormalize.length, 1);
1413     });
1414   });
1415
1416   describe(".name", () => {
1417     it("[[Get]] returns the correct name", () => {
1418       assertStrictEquals(stringNormalize.name, "stringNormalize");
1419     });
1420   });
1421 });
1422
1423 describe("stringPadEnd", () => {
1424   it("[[Call]] pads the end of the string", () => {
1425     assertStrictEquals(stringPadEnd("xx", 3), "xx ");
1426     assertStrictEquals(stringPadEnd("xx", 3, "o"), "xxo");
1427     assertStrictEquals(stringPadEnd("", 3, "xo"), "xox");
1428     assertStrictEquals(stringPadEnd("xx", 3, ""), "xx");
1429   });
1430
1431   it("[[Construct]] throws an error", () => {
1432     assertThrows(() => new stringPadEnd("", 1));
1433   });
1434
1435   describe(".length", () => {
1436     it("[[Get]] returns the correct length", () => {
1437       assertStrictEquals(stringPadEnd.length, 2);
1438     });
1439   });
1440
1441   describe(".name", () => {
1442     it("[[Get]] returns the correct name", () => {
1443       assertStrictEquals(stringPadEnd.name, "stringPadEnd");
1444     });
1445   });
1446 });
1447
1448 describe("stringPadStart", () => {
1449   it("[[Call]] pads the start of the string", () => {
1450     assertStrictEquals(stringPadStart("xx", 3), " xx");
1451     assertStrictEquals(stringPadStart("xx", 3, "o"), "oxx");
1452     assertStrictEquals(stringPadStart("", 3, "xo"), "xox");
1453     assertStrictEquals(stringPadStart("xx", 3, ""), "xx");
1454   });
1455
1456   it("[[Construct]] throws an error", () => {
1457     assertThrows(() => new stringPadStart("", 1));
1458   });
1459
1460   describe(".length", () => {
1461     it("[[Get]] returns the correct length", () => {
1462       assertStrictEquals(stringPadStart.length, 2);
1463     });
1464   });
1465
1466   describe(".name", () => {
1467     it("[[Get]] returns the correct name", () => {
1468       assertStrictEquals(stringPadStart.name, "stringPadStart");
1469     });
1470   });
1471 });
1472
1473 describe("stringRepeat", () => {
1474   it("[[Call]] repeats the string", () => {
1475     assertStrictEquals(stringRepeat("xx", 3), "xxxxxx");
1476     assertStrictEquals(stringRepeat("", 3), "");
1477     assertStrictEquals(stringRepeat("xx", 0), "");
1478   });
1479
1480   it("[[Call]] throws for negative repititions", () => {
1481     assertThrows(() => stringRepeat("", -1));
1482   });
1483
1484   it("[[Call]] throws for infinite repititions", () => {
1485     assertThrows(() => stringRepeat("", Infinity));
1486   });
1487
1488   it("[[Construct]] throws an error", () => {
1489     assertThrows(() => new stringRepeat("", 1));
1490   });
1491
1492   describe(".length", () => {
1493     it("[[Get]] returns the correct length", () => {
1494       assertStrictEquals(stringRepeat.length, 2);
1495     });
1496   });
1497
1498   describe(".name", () => {
1499     it("[[Get]] returns the correct name", () => {
1500       assertStrictEquals(stringRepeat.name, "stringRepeat");
1501     });
1502   });
1503 });
1504
1505 describe("stringReplace", () => {
1506   it("[[Call]] does the replacement akin to String::replace", () => {
1507     assertStrictEquals(
1508       stringReplace("it’s a failure", "failure", "success"),
1509       "it’s a success",
1510     );
1511     assertStrictEquals(
1512       stringReplace(
1513         "very success full",
1514         /([sc]+)[ue]?/,
1515         ($) => $.length,
1516       ),
1517       "very 2ccess full",
1518     );
1519     assertStrictEquals(
1520       stringReplace(
1521         "very success full",
1522         /([sc]+)[ue]?/g,
1523         (...$s) =>
1524           `${$s[0].length}`.repeat($s[1].length) +
1525           $s[0].substring($s[1].length),
1526       ),
1527       "very 2u33e22 full",
1528     );
1529   });
1530
1531   it("[[Construct]] throws an error", () => {
1532     assertThrows(() => new stringReplace("", /(?:)/, ""));
1533   });
1534
1535   describe(".length", () => {
1536     it("[[Get]] returns the correct length", () => {
1537       assertStrictEquals(stringReplace.length, 3);
1538     });
1539   });
1540
1541   describe(".name", () => {
1542     it("[[Get]] returns the correct name", () => {
1543       assertStrictEquals(stringReplace.name, "stringReplace");
1544     });
1545   });
1546 });
1547
1548 describe("stringReplaceAll", () => {
1549   it("[[Call]] does the match akin to String::replaceAll", () => {
1550     assertStrictEquals(
1551       stringReplaceAll("it’s a failure failure", "failure", "success"),
1552       "it’s a success success",
1553     );
1554     assertStrictEquals(
1555       stringReplaceAll(
1556         "very success full",
1557         /([sc]+)[ue]?/g,
1558         (...$s) =>
1559           `${$s[0].length}`.repeat($s[1].length) +
1560           $s[0].substring($s[1].length),
1561       ),
1562       "very 2u33e22 full",
1563     );
1564   });
1565
1566   it("[[Construct]] throws an error", () => {
1567     assertThrows(() => new stringReplaceAll("", /(?:)/g));
1568   });
1569
1570   describe(".length", () => {
1571     it("[[Get]] returns the correct length", () => {
1572       assertStrictEquals(stringReplaceAll.length, 3);
1573     });
1574   });
1575
1576   describe(".name", () => {
1577     it("[[Get]] returns the correct name", () => {
1578       assertStrictEquals(stringReplaceAll.name, "stringReplaceAll");
1579     });
1580   });
1581 });
1582
1583 describe("stringSearch", () => {
1584   it("[[Call]] does the search akin to String::search", () => {
1585     assertStrictEquals(
1586       stringSearch("very success full", /([sc]+)[ue]?/),
1587       5,
1588     );
1589     assertStrictEquals(
1590       stringSearch("very fail full", /([sc]+)[ue]?/),
1591       -1,
1592     );
1593   });
1594
1595   it("[[Construct]] throws an error", () => {
1596     assertThrows(() => new stringSearch("", /(?:)/));
1597   });
1598
1599   describe(".length", () => {
1600     it("[[Get]] returns the correct length", () => {
1601       assertStrictEquals(stringSearch.length, 2);
1602     });
1603   });
1604
1605   describe(".name", () => {
1606     it("[[Get]] returns the correct name", () => {
1607       assertStrictEquals(stringSearch.name, "stringSearch");
1608     });
1609   });
1610 });
1611
1612 describe("stringSlice", () => {
1613   it("[[Call]] slices the string akin to String::search", () => {
1614     assertStrictEquals(
1615       stringSlice("very success full", 5, 12),
1616       "success",
1617     );
1618     assertStrictEquals(
1619       stringSlice("very success full", -12, -5),
1620       "success",
1621     );
1622   });
1623
1624   it("[[Construct]] throws an error", () => {
1625     assertThrows(() => new stringSlice("", 0, 0));
1626   });
1627
1628   describe(".length", () => {
1629     it("[[Get]] returns the correct length", () => {
1630       assertStrictEquals(stringSlice.length, 3);
1631     });
1632   });
1633
1634   describe(".name", () => {
1635     it("[[Get]] returns the correct name", () => {
1636       assertStrictEquals(stringSlice.name, "stringSlice");
1637     });
1638   });
1639 });
1640
1641 describe("stringSplit", () => {
1642   it("[[Call]] splits the string akin to String::split", () => {
1643     assertEquals(stringSplit("success", ""), [
1644       "s",
1645       "u",
1646       "c",
1647       "c",
1648       "e",
1649       "s",
1650       "s",
1651     ]);
1652     assertEquals(stringSplit("success", /(?<=[aeiou])(?=[^aeiou])/), [
1653       "su",
1654       "cce",
1655       "ss",
1656     ]);
1657     assertEquals(stringSplit("success", "failure"), ["success"]);
1658   });
1659
1660   it("[[Call]] recognizes a limit", () => {
1661     assertEquals(stringSplit("success", "", 4), ["s", "u", "c", "c"]);
1662   });
1663
1664   it("[[Construct]] throws an error", () => {
1665     assertThrows(() => new stringSplit("", ""));
1666   });
1667
1668   describe(".length", () => {
1669     it("[[Get]] returns the correct length", () => {
1670       assertStrictEquals(stringSplit.length, 3);
1671     });
1672   });
1673
1674   describe(".name", () => {
1675     it("[[Get]] returns the correct name", () => {
1676       assertStrictEquals(stringSplit.name, "stringSplit");
1677     });
1678   });
1679 });
1680
1681 describe("stringStartsWith", () => {
1682   it("[[Call]] returns whether the string starts with the thing", () => {
1683     assertStrictEquals(
1684       stringStartsWith("success is had", "success "),
1685       true,
1686     );
1687     assertStrictEquals(
1688       stringStartsWith("no success is had", "success "),
1689       false,
1690     );
1691   });
1692
1693   it("[[Call]] accepts an offset", () => {
1694     assertStrictEquals(
1695       stringStartsWith("much success is had", "success ", 5),
1696       true,
1697     );
1698   });
1699
1700   it("[[Call]] returns true for an empty string test", () => {
1701     assertStrictEquals(stringEndsWith("", ""), true);
1702   });
1703
1704   it("[[Construct]] throws an error", () => {
1705     assertThrows(() => new stringStartsWith("", ""));
1706   });
1707
1708   describe(".length", () => {
1709     it("[[Get]] returns the correct length", () => {
1710       assertStrictEquals(stringStartsWith.length, 2);
1711     });
1712   });
1713
1714   describe(".name", () => {
1715     it("[[Get]] returns the correct name", () => {
1716       assertStrictEquals(stringStartsWith.name, "stringStartsWith");
1717     });
1718   });
1719 });
1720
1721 describe("stringStartsWith", () => {
1722   it("[[Call]] returns the string value of a string literal", () => {
1723     assertStrictEquals(stringValue("success"), "success");
1724   });
1725
1726   it("[[Call]] returns the string value of a string object", () => {
1727     const string = new String("success");
1728     Object.defineProperties(string, {
1729       toString: { value: () => "failure" },
1730       valueOf: { value: () => "failure" },
1731     });
1732     assertStrictEquals(stringValue(string), "success");
1733   });
1734
1735   it("[[Call]] throws for non‐strings", () => {
1736     assertThrows(() => stringValue(Object.create(String.prototype)));
1737   });
1738
1739   it("[[Construct]] throws an error", () => {
1740     assertThrows(() => new stringValue(""));
1741   });
1742
1743   describe(".length", () => {
1744     it("[[Get]] returns the correct length", () => {
1745       assertStrictEquals(stringValue.length, 1);
1746     });
1747   });
1748
1749   describe(".name", () => {
1750     it("[[Get]] returns the correct name", () => {
1751       assertStrictEquals(stringValue.name, "stringValue");
1752     });
1753   });
1754 });
1755
1756 describe("stripAndCollapseAsciiWhitespace", () => {
1757   it("[[Call]] collapses mixed inner whitespace", () => {
1758     assertEquals(
1759       stripAndCollapseAsciiWhitespace("🅰️\f \t\n🅱️\r\n\r🆎\n\f🅾️"),
1760       "🅰️ 🅱️ 🆎 🅾️",
1761     );
1762   });
1763
1764   it("[[Call]] trims leading and trailing whitespace", () => {
1765     assertStrictEquals(
1766       stripAndCollapseAsciiWhitespace(
1767         "\f\r\n\r\n \n\t\f 🅰️\f \t\n🅱️\r\n\r🆎\n\f🅾️\n\f",
1768       ),
1769       "🅰️ 🅱️ 🆎 🅾️",
1770     );
1771   });
1772
1773   it("[[Call]] returns the empty string for strings of whitespace", () => {
1774     assertStrictEquals(
1775       stripAndCollapseAsciiWhitespace("\f\r\n\r\n \n\t\f \n\f"),
1776       "",
1777     );
1778   });
1779
1780   it("[[Call]] does not collapse other kinds of whitespace", () => {
1781     assertEquals(
1782       stripAndCollapseAsciiWhitespace("a\u202F\u205F\xa0\v\0\bb"),
1783       "a\u202F\u205F\xa0\v\0\bb",
1784     );
1785   });
1786
1787   it("[[Construct]] throws an error", () => {
1788     assertThrows(() => new stripAndCollapseAsciiWhitespace(""));
1789   });
1790
1791   describe(".length", () => {
1792     it("[[Get]] returns the correct length", () => {
1793       assertStrictEquals(stripAndCollapseAsciiWhitespace.length, 1);
1794     });
1795   });
1796
1797   describe(".name", () => {
1798     it("[[Get]] returns the correct name", () => {
1799       assertStrictEquals(
1800         stripAndCollapseAsciiWhitespace.name,
1801         "stripAndCollapseAsciiWhitespace",
1802       );
1803     });
1804   });
1805 });
1806
1807 describe("stripLeadingAndTrailingAsciiWhitespace", () => {
1808   it("[[Call]] trims leading and trailing whitespace", () => {
1809     assertStrictEquals(
1810       stripLeadingAndTrailingAsciiWhitespace(
1811         "\f\r\n\r\n \n\t\f 🅰️🅱️🆎🅾️\n\f",
1812       ),
1813       "🅰️🅱️🆎🅾️",
1814     );
1815   });
1816
1817   it("[[Call]] returns the empty string for strings of whitespace", () => {
1818     assertStrictEquals(
1819       stripLeadingAndTrailingAsciiWhitespace("\f\r\n\r\n \n\t\f \n\f"),
1820       "",
1821     );
1822   });
1823
1824   it("[[Call]] does not trim other kinds of whitespace", () => {
1825     assertEquals(
1826       stripLeadingAndTrailingAsciiWhitespace(
1827         "\v\u202F\u205Fx\0\b\xa0",
1828       ),
1829       "\v\u202F\u205Fx\0\b\xa0",
1830     );
1831   });
1832
1833   it("[[Call]] does not adjust inner whitespace", () => {
1834     assertEquals(
1835       stripLeadingAndTrailingAsciiWhitespace("a   b"),
1836       "a   b",
1837     );
1838   });
1839
1840   it("[[Construct]] throws an error", () => {
1841     assertThrows(() => new stripLeadingAndTrailingAsciiWhitespace(""));
1842   });
1843
1844   describe(".length", () => {
1845     it("[[Get]] returns the correct length", () => {
1846       assertStrictEquals(
1847         stripLeadingAndTrailingAsciiWhitespace.length,
1848         1,
1849       );
1850     });
1851   });
1852
1853   describe(".name", () => {
1854     it("[[Get]] returns the correct name", () => {
1855       assertStrictEquals(
1856         stripLeadingAndTrailingAsciiWhitespace.name,
1857         "stripLeadingAndTrailingAsciiWhitespace",
1858       );
1859     });
1860   });
1861 });
1862
1863 describe("substring", () => {
1864   it("[[Call]] returns the substring", () => {
1865     assertStrictEquals(
1866       substring("success", 0),
1867       "success",
1868     );
1869     assertStrictEquals(
1870       substring("very success full", 5, 12),
1871       "success",
1872     );
1873   });
1874
1875   it("[[Construct]] throws an error", () => {
1876     assertThrows(() => new substring("", 0));
1877   });
1878
1879   describe(".length", () => {
1880     it("[[Get]] returns the correct length", () => {
1881       assertStrictEquals(substring.length, 3);
1882     });
1883   });
1884
1885   describe(".name", () => {
1886     it("[[Get]] returns the correct name", () => {
1887       assertStrictEquals(substring.name, "substring");
1888     });
1889   });
1890 });
1891
1892 describe("toScalarValueString", () => {
1893   it("[[Call]] replaces invalid values", () => {
1894     assertStrictEquals(
1895       toScalarValueString("Ii🎙\uDFFF\uDD96\uD83C\uD800🆗☺"),
1896       "Ii🎙\uFFFD\uFFFD\uFFFD\uFFFD🆗☺",
1897     );
1898   });
1899
1900   it("[[Construct]] throws an error", () => {
1901     assertThrows(() => new toScalarValueString(""));
1902   });
1903
1904   describe(".length", () => {
1905     it("[[Get]] returns the correct length", () => {
1906       assertStrictEquals(toScalarValueString.length, 1);
1907     });
1908   });
1909
1910   describe(".name", () => {
1911     it("[[Get]] returns the correct name", () => {
1912       assertStrictEquals(
1913         toScalarValueString.name,
1914         "toScalarValueString",
1915       );
1916     });
1917   });
1918 });
1919
1920 describe("toString", () => {
1921   it("[[Call]] converts to a string", () => {
1922     assertStrictEquals(
1923       toString({
1924         toString() {
1925           return "success";
1926         },
1927       }),
1928       "success",
1929     );
1930   });
1931
1932   it("[[Call]] throws when provided a symbol", () => {
1933     assertThrows(() => toString(Symbol()));
1934   });
1935
1936   it("[[Construct]] throws an error", () => {
1937     assertThrows(() => new toString(""));
1938   });
1939
1940   describe(".length", () => {
1941     it("[[Get]] returns the correct length", () => {
1942       assertStrictEquals(toString.length, 1);
1943     });
1944   });
1945
1946   describe(".name", () => {
1947     it("[[Get]] returns the correct name", () => {
1948       assertStrictEquals(toString.name, "toString");
1949     });
1950   });
1951 });