Implement Model-Driven-Views spec for Dart

pkg/mdv_observe/test/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 'dart:async';
+import 'package:mdv_observe/mdv_observe.dart';
+import 'package:unittest/unittest.dart';
+import 'utils.dart';
+
+main() {
+  // Note: to test the basic Observable system, we use ObservableBox due to its
+  // simplicity.
+
+  const _VALUE = const Symbol('value');
+
+  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++;
+        expectChanges(records, [_record(_VALUE), _record(_VALUE)]);
+      }));
+      t.value = 41;
+      t.value = 42;
+      expect(called, 0);
+    });
+
+    test('cause changes in handler', () {
+      var t = new ObservableBox<int>(123);
+      int called = 0;
+
+      t.changes.listen(expectAsync1((records) {
+        called++;
+        expectChanges(records, [_record(_VALUE)]);
+        if (called == 1) {
+          // Cause another change
+          t.value = 777;
+        }
+      }, count: 2));
+
+      t.value = 42;
+    });
+
+    test('multiple observers', () {
+      var t = new ObservableBox<int>(123);
+
+      verifyRecords(records) {
+        expectChanges(records, [_record(_VALUE), _record(_VALUE)]);
+      };
+
+      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;
+      expectChanges(records, [], reason: 'changes delived async');
+
+      deliverChangeRecords();
+      expectChanges(records,
+          [_record(_VALUE), _record(_VALUE)]);
+      records.clear();
+
+      t.value = 777;
+      expectChanges(records, [], reason: 'changes delived async');
+
+      deliverChangeRecords();
+      expectChanges(records, [_record(_VALUE)]);
+
+      // Has no effect if there are no changes
+      deliverChangeRecords();
+      expectChanges(records, [_record(_VALUE)]);
+    });
+
+    test('cancel listening', () {
+      var t = new ObservableBox<int>(123);
+      var sub;
+      sub = t.changes.listen(expectAsync1((records) {
+        expectChanges(records, [_record(_VALUE)]);
+        sub.cancel();
+        t.value = 777;
+      }));
+      t.value = 42;
+    });
+
+    test('cancel and reobserve', () {
+      var t = new ObservableBox<int>(123);
+      var sub;
+      sub = t.changes.listen(expectAsync1((records) {
+        expectChanges(records, [_record(_VALUE)]);
+        sub.cancel();
+
+        runAsync(expectAsync0(() {
+          sub = t.changes.listen(expectAsync1((records) {
+            expectChanges(records, [_record(_VALUE)]);
+          }));
+          t.value = 777;
+        }));
+      }));
+      t.value = 42;
+    });
+  });
+}
+
+_record(key) => new PropertyChangeRecord(key);