Add a CanonicalizedMap class to pkg/collection.

pkg/collection/test/canonicalized_map_test.dart

+// Copyright (c) 2014, 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.
+
+import "package:collection/collection.dart";
+import "package:unittest/unittest.dart";
+
+void main() {
+  group("with an empty canonicalized map", () {
+    var map;
+    setUp(() {
+      map = new CanonicalizedMap<int, String, String>(int.parse,
+          isValidKey: new RegExp(r"^\d+$").hasMatch);
+    });
+
+    test("canonicalizes keys on set and get", () {
+      map["1"] = "value";
+      expect(map["01"], equals("value"));
+    });
+
+    test("get returns null for uncanonicalizable key", () {
+      expect(map["foo"], isNull);
+    });
+
+    test("canonicalizes keys for addAll", () {
+      map.addAll({
+        "1": "value 1",
+        "2": "value 2",
+        "3": "value 3"
+      });
+      expect(map["01"], equals("value 1"));
+      expect(map["02"], equals("value 2"));
+      expect(map["03"], equals("value 3"));
+    });
+
+    test("uses the final value for addAll collisions", () {
+      map.addAll({
+        "1": "value 1",
+        "01": "value 2",
+        "001": "value 3"
+      });
+      expect(map.length, equals(1));
+      expect(map["0001"], equals("value 3"));
+    });
+
+    test("clear clears the map", () {
+      map.addAll({
+        "1": "value 1",
+        "2": "value 2",
+        "3": "value 3"
+      });
+      expect(map, isNot(isEmpty));
+      map.clear();
+      expect(map, isEmpty);
+    });
+
+    test("canonicalizes keys for containsKey", () {
+      map["1"] = "value";
+      expect(map.containsKey("01"), isTrue);
+      expect(map.containsKey("2"), isFalse);
+    });
+
+    test("containsKey returns false for uncanonicalizable key", () {
+      expect(map.containsKey("foo"), isFalse);
+    });
+
+    test("canonicalizes keys for putIfAbsent", () {
+      map["1"] = "value";
+      expect(map.putIfAbsent("01", () => throw "shouldn't run"),
+             equals("value"));
+      expect(map.putIfAbsent("2", () => "new value"), equals("new value"));
+    });
+
+    test("canonicalizes keys for remove", () {
+      map["1"] = "value";
+      expect(map.remove("2"), isNull);
+      expect(map.remove("01"), equals("value"));
+      expect(map, isEmpty);
+    });
+
+    test("remove returns null for uncanonicalizable key", () {
+      expect(map.remove("foo"), isNull);
+    });
+
+    test("containsValue returns whether a value is in the map", () {
+      map["1"] = "value";
+      expect(map.containsValue("value"), isTrue);
+      expect(map.containsValue("not value"), isFalse);
+    });
+
+    test("isEmpty returns whether the map is empty", () {
+      expect(map.isEmpty, isTrue);
+      map["1"] = "value";
+      expect(map.isEmpty, isFalse);
+      map.remove("01");
+      expect(map.isEmpty, isTrue);
+    });
+
+    test("isNotEmpty returns whether the map isn't empty", () {
+      expect(map.isNotEmpty, isFalse);
+      map["1"] = "value";
+      expect(map.isNotEmpty, isTrue);
+      map.remove("01");
+      expect(map.isNotEmpty, isFalse);
+    });
+
+    test("length returns the number of pairs in the map", () {
+      expect(map.length, equals(0));
+      map["1"] = "value 1";
+      expect(map.length, equals(1));
+      map["01"] = "value 01";
+      expect(map.length, equals(1));
+      map["02"] = "value 02";
+      expect(map.length, equals(2));
+    });
+
+    test("uses original keys for keys", () {
+      map["001"] = "value 1";
+      map["02"] = "value 2";
+      expect(map.keys, equals(["001", "02"]));
+    });
+
+    test("uses original keys for forEach", () {
+      map["001"] = "value 1";
+      map["02"] = "value 2";
+
+      var keys = [];
+      map.forEach((key, value) => keys.add(key));
+      expect(keys, equals(["001", "02"]));
+    });
+
+    test("values returns all values in the map", () {
+      map.addAll({
+        "1": "value 1",
+        "01": "value 01",
+        "2": "value 2",
+        "03": "value 03"
+      });
+
+      expect(map.values, equals(["value 01", "value 2", "value 03"]));
+    });
+  });
+
+  group("CanonicalizedMap.from", () {
+    test("canonicalizes its keys", () {
+      var map = new CanonicalizedMap.from({
+        "1": "value 1",
+        "2": "value 2",
+        "3": "value 3"
+      }, int.parse);
+      expect(map["01"], equals("value 1"));
+      expect(map["02"], equals("value 2"));
+      expect(map["03"], equals("value 3"));
+    });
+
+    test("uses the final value for collisions", () {
+      var map = new CanonicalizedMap.from({
+        "1": "value 1",
+        "01": "value 2",
+        "001": "value 3"
+      }, int.parse);
+      expect(map.length, equals(1));
+      expect(map["0001"], equals("value 3"));
+    });
+  });
+}