Implement Model-Driven-Views spec for Dart

tests/lib/observe/observe_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.
+
+import '../../../pkg/unittest/lib/unittest.dart';
+import '../../../sdk/lib/observe/observe.dart';
+
+main() {
+  // Note: to test the basic Observable system, we use ObservableBox due to its
+  // simplicity.
+
+  group('ObservableBox', () {
+    test('no observers', () {
+      var t = new ObservableBox<int>(123);
+      expect(t.value, 123);
+      t.value = 42;
+      expect(t.value, 42);
+      expect(t.hasObservers, false);
+    });
+
+    test('listen adds an observer', () {
+      var t = new ObservableBox<int>(123);
+      expect(t.hasObservers, false);
+
+      t.changes.listen((n) {});
+      expect(t.hasObservers, true);
+    });
+
+    test('changes delived async', () {
+      var t = new ObservableBox<int>(123);
+      int called = 0;
+
+      t.changes.listen(expectAsync1((records) {
+        called++;
+        expect(records, [_record('value', 123, 41), _record('value', 41, 42)]);
+      }));
+      t.value = 41;
+      t.value = 42;
+      expect(called, 0);
+    });
+
+    test('cause changes in handler', () {
+      var t = new ObservableBox<int>(123);
+      t.changes.listen(expectAsync1((records) {
+        expect(records.length, 1);
+        var record = records[0];
+        if (record.oldValue == 123) {
+          expect(record.newValue, 42);
+          // Cause another change
+          t.value = 777;
+        } else {
+          expect(record.oldValue, 42);
+          expect(record.newValue, 777);
+        }
+      }, count: 2));
+
+      t.value = 42;
+    });
+
+    test('multiple observers', () {
+      var t = new ObservableBox<int>(123);
+
+      verifyRecords(records) {
+        expect(records, [_record('value', 123, 41), _record('value', 41, 42)]);
+      };
+
+      t.changes.listen(expectAsync1(verifyRecords));
+      t.changes.listen(expectAsync1(verifyRecords));
+
+      t.value = 41;
+      t.value = 42;
+    });
+
+    test('deliverChangeRecords', () {
+      var t = new ObservableBox<int>(123);
+      var records = [];
+      t.changes.listen((r) { records.addAll(r); });
+      t.value = 41;
+      t.value = 42;
+      expect(records, [], reason: 'changes delived async');
+
+      deliverChangeRecords();
+      expect(records, [_record('value', 123, 41), _record('value', 41, 42)]);
+      records.clear();
+
+      t.value = 777;
+      expect(records, [], reason: 'changes delived async');
+
+      deliverChangeRecords();
+      expect(records, [_record('value', 42, 777)]);
+
+      // Has no effect if there are no changes
+      deliverChangeRecords();
+      expect(records, [_record('value', 42, 777)]);
+    });
+
+    test('cancel listening', () {
+      var t = new ObservableBox<int>(123);
+      var sub;
+      sub = t.changes.listen(expectAsync1((records) {
+        expect(records, [_record('value', 123, 42)]);
+        sub.cancel();
+        t.value = 777;
+      }));
+      t.value = 42;
+    });
+  });
+
+  // We only really support equality on these for testing purposes.
+  // However we need .hashCode because we've implemented operator ==.
+  test('ChangeRecord.hashCode', () {
+    var a = _record('a',  1, null, ChangeRecord.REMOVE);
+    var b = _record('a',  1, null, ChangeRecord.REMOVE);
+    var c = _record('b',  1, null, ChangeRecord.REMOVE);
+    expect(a.hashCode, b.hashCode, reason: 'a == b');
+    expect(b.hashCode, isNot(equals(c.hashCode)), reason: 'b != c');
+  });
+}
+
+_record(key, oldValue, newValue, [kind = ChangeRecord.FIELD]) =>
+    new ChangeRecord(key, oldValue, newValue, kind: kind);