Migrate test block 3 to Dart 2.0.

tests/corelib/collection_to_string_test.dart

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-/**
- * Tests for the toString methods on collections and maps.
- */
-
-library collection_to_string;
-
-import "package:expect/expect.dart";
-import 'dart:collection' show Queue, LinkedHashMap;
-import 'dart:math' as Math;
-
-// TODO(jjb): seed random number generator when API allows it
-
-const int NUM_TESTS = 300;
-const int MAX_COLLECTION_SIZE = 7;
-
-Math.Random rand;
-
-main() {
-  rand = new Math.Random();
-  smokeTest();
-  exactTest();
-  inexactTest();
-}
-
-/**
- * Test a few simple examples.
- */
-void smokeTest() {
-  // Non-const lists
-  Expect.equals([].toString(), '[]');
-  Expect.equals([1].toString(), '[1]');
-  Expect.equals(['Elvis'].toString(), '[Elvis]');
-  Expect.equals([null].toString(), '[null]');
-  Expect.equals([1, 2].toString(), '[1, 2]');
-  Expect.equals(['I', 'II'].toString(), '[I, II]');
-  Expect.equals(
-      [
-        [1, 2],
-        [3, 4],
-        [5, 6]
-      ].toString(),
-      '[[1, 2], [3, 4], [5, 6]]');
-
-  // Const lists
-  Expect.equals((const []).toString(), '[]');
-  Expect.equals((const [1]).toString(), '[1]');
-  Expect.equals((const ['Elvis']).toString(), '[Elvis]');
-  Expect.equals((const [null]).toString(), '[null]');
-  Expect.equals((const [1, 2]).toString(), '[1, 2]');
-  Expect.equals((const ['I', 'II']).toString(), '[I, II]');
-  Expect.equals(
-      (const [
-        const [1, 2],
-        const [3, 4],
-        const [5, 6]
-      ])
-          .toString(),
-      '[[1, 2], [3, 4], [5, 6]]');
-
-  // Non-const maps - Note that all keys are strings; the spec currently demands this
-  Expect.equals({}.toString(), '{}');
-  Expect.equals({'Elvis': 'King'}.toString(), '{Elvis: King}');
-  Expect.equals({'Elvis': null}.toString(), '{Elvis: null}');
-  Expect.equals({'I': 1, 'II': 2}.toString(), '{I: 1, II: 2}');
-  Expect.equals(
-      {
-        'X': {'I': 1, 'II': 2},
-        'Y': {'III': 3, 'IV': 4},
-        'Z': {'V': 5, 'VI': 6}
-      }.toString(),
-      '{X: {I: 1, II: 2}, Y: {III: 3, IV: 4}, Z: {V: 5, VI: 6}}');
-
-  // Const maps
-  Expect.equals(const {}.toString(), '{}');
-  Expect.equals(const {'Elvis': 'King'}.toString(), '{Elvis: King}');
-  Expect.equals({'Elvis': null}.toString(), '{Elvis: null}');
-  Expect.equals(const {'I': 1, 'II': 2}.toString(), '{I: 1, II: 2}');
-  Expect.equals(
-      const {
-        'X': const {'I': 1, 'II': 2},
-        'Y': const {'III': 3, 'IV': 4},
-        'Z': const {'V': 5, 'VI': 6}
-      }.toString(),
-      '{X: {I: 1, II: 2}, Y: {III: 3, IV: 4}, Z: {V: 5, VI: 6}}');
-}
-
-// SERIOUS "BASHER" TESTS
-
-/**
- * Generate a bunch of random collections (including Maps), and test that
- * there string form is as expected. The collections include collections
- * as elements, keys, and values, and include recursive references.
- *
- * This test restricts itself to collections with well-defined iteration
- * orders (i.e., no HashSet, HashMap).
- */
-void exactTest() {
-  for (int i = 0; i < NUM_TESTS; i++) {
-    // Choose a size from 0 to MAX_COLLECTION_SIZE, favoring larger sizes
-    int size =
-        Math.sqrt(random(MAX_COLLECTION_SIZE * MAX_COLLECTION_SIZE)).toInt();
-
-    StringBuffer stringRep = new StringBuffer();
-    Object o = randomCollection(size, stringRep, exact: true);
-    print(stringRep);
-    print(o);
-    Expect.equals(o.toString(), stringRep.toString());
-  }
-}
-
-/**
- * Generate a bunch of random collections (including Maps), and test that
- * there string form is as expected. The collections include collections
- * as elements, keys, and values, and include recursive references.
- *
- * This test includes collections with ill-defined iteration orders (i.e.,
- * HashSet, HashMap). As a consequence, it can't use equality tests on the
- * string form. Instead, it performs equality tests on their "alphagrams."
- * This might allow false positives, but it does give a fair amount of
- * confidence.
- */
-void inexactTest() {
-  for (int i = 0; i < NUM_TESTS; i++) {
-    // Choose a size from 0 to MAX_COLLECTION_SIZE, favoring larger sizes
-    int size =
-        Math.sqrt(random(MAX_COLLECTION_SIZE * MAX_COLLECTION_SIZE)).toInt();
-
-    StringBuffer stringRep = new StringBuffer();
-    Object o = randomCollection(size, stringRep, exact: false);
-    print(stringRep);
-    print(o);
-    Expect.equals(alphagram(o.toString()), alphagram(stringRep.toString()));
-  }
-}
-
-/**
- * Return a random collection (or Map) of the specified size, placing its
- * string representation into the given string buffer.
- *
- * If exact is true, the returned collections will not be, and will not contain
- * a collection with ill-defined iteration order (i.e., a HashSet or HashMap).
- */
-Object randomCollection(int size, StringBuffer stringRep, {bool exact}) {
-  return randomCollectionHelper(size, exact, stringRep, []);
-}
-
-/**
- * Return a random collection (or map) of the specified size, placing its
- * string representation into the given string buffer. The beingMade
- * parameter is a list of collections currently under construction, i.e.,
- * candidates for recursive references.
- *
- * If exact is true, the returned collections will not be, and will not contain
- * a collection with ill-defined iteration order (i.e., a HashSet or HashMap).
- */
-Object randomCollectionHelper(
-    int size, bool exact, StringBuffer stringRep, List beingMade) {
-  double interfaceFrac = rand.nextDouble();
-
-  if (exact) {
-    if (interfaceFrac < 1 / 3) {
-      return randomList(size, exact, stringRep, beingMade);
-    } else if (interfaceFrac < 2 / 3) {
-      return randomQueue(size, exact, stringRep, beingMade);
-    } else {
-      return randomMap(size, exact, stringRep, beingMade);
-    }
-  } else {
-    if (interfaceFrac < 1 / 4) {
-      return randomList(size, exact, stringRep, beingMade);
-    } else if (interfaceFrac < 2 / 4) {
-      return randomQueue(size, exact, stringRep, beingMade);
-    } else if (interfaceFrac < 3 / 4) {
-      return randomSet(size, exact, stringRep, beingMade);
-    } else {
-      return randomMap(size, exact, stringRep, beingMade);
-    }
-  }
-}
-
-/**
- * Return a random List of the specified size, placing its string
- * representation into the given string buffer. The beingMade
- * parameter is a list of collections currently under construction, i.e.,
- * candidates for recursive references.
- *
- * If exact is true, the returned collections will not be, and will not contain
- * a collection with ill-defined iteration order (i.e., a HashSet or HashMap).
- */
-List randomList(int size, bool exact, StringBuffer stringRep, List beingMade) {
-  return populateRandomCollection(size, exact, stringRep, beingMade, [], "[]");
-}
-
-/**
- * Like randomList, but returns a queue.
- */
-Queue randomQueue(
-    int size, bool exact, StringBuffer stringRep, List beingMade) {
-  return populateRandomCollection(
-      size, exact, stringRep, beingMade, new Queue(), "{}");
-}
-
-/**
- * Like randomList, but returns a Set.
- */
-Set randomSet(int size, bool exact, StringBuffer stringRep, List beingMade) {
-  // Until we have LinkedHashSet, method will only be called with exact==true
-  return populateRandomSet(size, exact, stringRep, beingMade, new Set());
-}
-
-/**
- * Like randomList, but returns a map.
- */
-Map randomMap(int size, bool exact, StringBuffer stringRep, List beingMade) {
-  if (exact) {
-    return populateRandomMap(
-        size, exact, stringRep, beingMade, new LinkedHashMap());
-  } else {
-    return populateRandomMap(size, exact, stringRep, beingMade,
-        randomBool() ? new Map() : new LinkedHashMap());
-  }
-}
-
-/**
- * Populates the given empty collection with elements, emitting the string
- * representation of the collection to stringRep.  The beingMade parameter is
- * a list of collections currently under construction, i.e., candidates for
- * recursive references.
- *
- * If exact is true, the elements of the returned collections will not be,
- * and will not contain a collection with ill-defined iteration order
- * (i.e., a HashSet or HashMap).
- */
-populateRandomCollection(int size, bool exact, StringBuffer stringRep,
-    List beingMade, var coll, String delimiters) {
-  beingMade.add(coll);
-  int start = stringRep.length;
-
-  stringRep.write(delimiters[0]);
-
-  List indices = [];
-  for (int i = 0; i < size; i++) {
-    indices.add(stringRep.length);
-    if (i != 0) stringRep.write(', ');
-    coll.add(randomElement(random(size), exact, stringRep, beingMade));
-  }
-  if (size > 5 && delimiters == "()") {
-    const int MAX_LENGTH = 80;
-    const int MIN_COUNT = 3;
-    const int MAX_COUNT = 100;
-    // It's an iterable, it may omit some elements.
-    int end = stringRep.length;
-    if (size > MAX_COUNT) {
-      // Last two elements are also omitted, just find the first three or
-      // first 60 characters.
-      for (int i = MIN_COUNT; i < size; i++) {
-        int startIndex = indices[i];
-        if (startIndex - start > MAX_LENGTH - 6) {
-          // Limit - ", ...)".length.
-          String prefix = stringRep.toString().substring(0, startIndex);
-          stringRep.clear();
-          stringRep.write(prefix);
-          stringRep.write(", ...");
-        }
-      }
-    } else if (stringRep.length - start > MAX_LENGTH - 1) {
-      // 80 - ")".length.
-      // Last two elements are always included. Middle ones may be omitted.
-      int lastTwoLength = end - indices[indices.length - 2];
-      // Try to find first element to omit.
-      for (int i = 3; i <= size - 3; i++) {
-        int elementEnd = indices[i + 1];
-        int lengthAfter = elementEnd - start;
-        int ellipsisSize = 5; // ", ...".length
-        if (i == size - 3) ellipsisSize = 0; // No ellipsis if we hit the end.
-        if (lengthAfter + ellipsisSize + lastTwoLength > MAX_LENGTH - 1) {
-          // Omit this element and everything up to the last two.
-          int elementStart = indices[i];
-          // Rewrite string buffer by copying it out, clearing, and putting
-          // the parts back in.
-          String buffer = stringRep.toString();
-          String prefix = buffer.substring(0, elementStart);
-          String suffix = buffer.substring(end - lastTwoLength, end);
-          stringRep.clear();
-          stringRep.write(prefix);
-          stringRep.write(", ...");
-          stringRep.write(suffix);
-          break;
-        }
-      }
-    }
-  }
-
-  stringRep.write(delimiters[1]);
-  beingMade.removeLast();
-  return coll;
-}
-
-/** Like populateRandomCollection, but for sets (elements must be hashable) */
-Set populateRandomSet(
-    int size, bool exact, StringBuffer stringRep, List beingMade, Set set) {
-  stringRep.write('{');
-
-  for (int i = 0; i < size; i++) {
-    if (i != 0) stringRep.write(', ');
-    set.add(i);
-    stringRep.write(i);
-  }
-
-  stringRep.write('}');
-  return set;
-}
-
-/** Like populateRandomCollection, but for maps. */
-Map populateRandomMap(
-    int size, bool exact, StringBuffer stringRep, List beingMade, Map map) {
-  beingMade.add(map);
-  stringRep.write('{');
-
-  for (int i = 0; i < size; i++) {
-    if (i != 0) stringRep.write(', ');
-
-    int key = i; // Ensures no duplicates
-    stringRep.write(key);
-    stringRep.write(': ');
-    Object val = randomElement(random(size), exact, stringRep, beingMade);
-    map[key] = val;
-  }
-
-  stringRep.write('}');
-  beingMade.removeLast();
-  return map;
-}
-
-/**
- * Generates a random element which can be an int, a collection, or a map,
- * and emits it to StringRep. The beingMade parameter is a list of collections
- * currently under construction, i.e., candidates for recursive references.
- *
- * If exact is true, the returned element will not be, and will not contain
- * a collection with ill-defined iteration order (i.e., a HashSet or HashMap).
- */
-Object randomElement(
-    int size, bool exact, StringBuffer stringRep, List beingMade) {
-  Object result;
-  double elementTypeFrac = rand.nextDouble();
-  if (elementTypeFrac < 1 / 3) {
-    result = random(1000);
-    stringRep.write(result);
-  } else if (elementTypeFrac < 2 / 3) {
-    // Element is a random (new) collection
-    result = randomCollectionHelper(size, exact, stringRep, beingMade);
-  } else {
-    // Element is a random recursive ref
-    result = beingMade[random(beingMade.length)];
-    if (result is List) {
-      stringRep.write('[...]');
-    } else if (result is Set || result is Map || result is Queue) {
-      stringRep.write('{...}');
-    } else {
-      stringRep.write('(...)');
-    }
-  }
-  return result;
-}
-
-/** Returns a random int on [0, max) */
-int random(int max) {
-  return rand.nextInt(max);
-}
-
-/** Returns a random boolean value. */
-bool randomBool() {
-  return rand.nextBool();
-}
-
-/** Returns the alphabetized characters in a string. */
-String alphagram(String s) {
-  // Calling [toList] to convert unmodifiable list to normal list.
-  List<int> chars = s.codeUnits.toList();
-  chars.sort((int a, int b) => a - b);
-  return new String.fromCharCodes(chars);
-}