Reapply "New implementation of {,Linked}Hash{Set,Map}."

tests/corelib/hash_set_test.dart

+// Copyright (c) 2013, 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 of hash set behavior, with focus in iteration and concurrent
+// modification errors.
+
+library hash_map2_test;
+import 'dart:collection';
+
+testSet(Set newSet(), Set newSetFrom(Set from)) {
+  Set gen(int from, int to) =>
+      new Set.from(new Iterable.generate(to - from, (n) => n + from));
+
+  bool odd(int n) => (n & 1) == 1;
+  bool even(int n) => (n & 1) == 0;
+
+  {  // Test growing to largish capacity.
+    Set set = newSet();
+
+    for (int i = 0; i < 256; i++) {
+      set.add(i);
+    }
+    set.addAll(gen(256, 512));
+    set.addAll(newSetFrom(gen(512, 1000)));
+    Expect.equals(1000, set.length);
+
+    // Remove half.
+    for (int i = 0; i < 1000; i += 2) set.remove(i);
+    Expect.equals(500, set.length);
+    Expect.isFalse(set.any(even));
+    Expect.isTrue(set.every(odd));
+
+    // Re-add all.
+    set.addAll(gen(0, 1000));
+    Expect.equals(1000, set.length);
+  }
+
+  {  // Test having many deleted elements.
+    Set set = newSet();
+    set.add(0);
+    for (int i = 0; i < 1000; i++) {
+      set.add(i + 1);
+      set.remove(i);
+      Expect.equals(1, set.length);
+    }
+  }
+
+  {  // Test having many elements with same hashCode
+    Set set = newSet();
+    for (int i = 0; i < 1000; i++) {
+      set.add(new BadHashCode());
+    }
+    Expect.equals(1000, set.length);
+  }
+
+  {  // Check concurrent modification
+    Set set = newSet()..add(0)..add(1);
+
+    {  // Test adding before a moveNext.
+      Iterator iter = set.iterator;
+      iter.moveNext();
+      set.add(1);  // Updating existing key isn't a modification.
+      iter.moveNext();
+      set.add(2);
+      Expect.throws(iter.moveNext, (e) => e is Error);
+    }
+
+    {  // Test adding after last element.
+      Iterator iter = set.iterator;
+      Expect.equals(3, set.length);
+      iter.moveNext();
+      iter.moveNext();
+      iter.moveNext();
+      set.add(3);
+      Expect.throws(iter.moveNext, (e) => e is Error);
+    }
+
+    {  // Test removing during iteration.
+      Iterator iter = set.iterator;
+      iter.moveNext();
+      set.remove(1000);  // Not a modification if it's not there.
+      iter.moveNext();
+      int n = iter.current;
+      set.remove(n);
+      // Removing doesn't change current.
+      Expect.equals(n, iter.current);
+      Expect.throws(iter.moveNext, (e) => e is Error);
+    }
+
+    {  // Test removing after last element.
+      Iterator iter = set.iterator;
+      Expect.equals(3, set.length);
+      iter.moveNext();
+      iter.moveNext();
+      iter.moveNext();
+      int n = iter.current;
+      set.remove(n);
+      // Removing doesn't change current.
+      Expect.equals(n, iter.current);
+      Expect.throws(iter.moveNext, (e) => e is Error);
+    }
+
+    {  // Test that updating value doesn't cause error.
+      Iterator iter = set.iterator;
+      Expect.equals(2, set.length);
+      iter.moveNext();
+      int n = iter.current;
+      set.add(n);
+      iter.moveNext();
+      Expect.isTrue(set.contains(iter.current));
+    }
+
+    {  // Check adding many existing values isn't considered modification.
+      Set set2 = newSet();
+      for (var value in set) {
+        set2.add(value);
+      }
+      Iterator iter = set.iterator;
+      set.addAll(set2);
+      // Shouldn't throw.
+      iter.moveNext();
+    }
+  }
+
+  {  // Check that updating existing elements is not a modification.
+     // This must be the case even if the underlying data structure is
+     // nearly full.
+     for (int i = 1; i < 128; i++) {
+        // Create maps of different sizes, some of which should be
+        // at a limit of the underlying data structure.
+        Set set = newSetFrom(gen(0, i));
+        Iterator iter = set.iterator;
+        for (int j = 0; j < i; j++) {
+          set.add(j);
+        }
+        iter.moveNext();  // Should not throw.
+
+        for (int j = 1; j < i; j++) {
+          set.remove(j);
+        }
+        iter = set.iterator;
+        set.add(0);
+        iter.moveNext();  // Should not throw.
+     }
+  }
+
+  {  // Check that null can be in the set.
+    Set set = newSet();
+    set.add(null);
+    Expect.equals(1, set.length);
+    Expect.isTrue(set.contains(null));
+    Expect.isNull(set.first);
+    Expect.isNull(set.last);
+    set.add(null);
+    Expect.equals(1, set.length);
+    Expect.isTrue(set.contains(null));
+    set.remove(null);
+    Expect.isTrue(set.isEmpty);
+    Expect.isFalse(set.contains(null));
+
+    // Created using Set.from.
+    set = newSetFrom([null]);
+    Expect.equals(1, set.length);
+    Expect.isTrue(set.contains(null));
+    Expect.isNull(set.first);
+    Expect.isNull(set.last);
+    set.add(null);
+    Expect.equals(1, set.length);
+    Expect.isTrue(set.contains(null));
+    set.remove(null);
+    Expect.isTrue(set.isEmpty);
+    Expect.isFalse(set.contains(null));
+
+    // Set that grows with null in it.
+    set = newSetFrom([1, 2, 3, null, 4, 5, 6]);
+    Expect.equals(7, set.length);
+    for (int i = 7; i < 128; i++) {
+      set.add(i);
+    }
+    Expect.equals(128, set.length);
+    Expect.isTrue(set.contains(null));
+    set.add(null);
+    Expect.equals(128, set.length);
+    Expect.isTrue(set.contains(null));
+    set.remove(null);
+    Expect.equals(127, set.length);
+    Expect.isFalse(set.contains(null));
+  }
+}
+
+void main() {
+  testSet(() => new HashSet(), (m) => new HashSet.from(m));
+  testSet(() => new LinkedHashSet(), (m) => new LinkedHashSet.from(m));
+}
+
+
+class BadHashCode {
+  static int idCounter = 0;
+  final int id;
+  BadHashCode() : id = idCounter++;
+  int get hashCode => 42;
+  // operator == is identity.
+  // Can't make a bad compareTo that isn't invalid.
+  int compareTo(BadHashCode other) => id - other.id;
+}