Merge pull request #24 from LoveCommunity/feature/subject

add `Subject` interface

lib/src/observables/observables.dart

@@ -3,3 +3,4 @@ export 'package:disposal/disposal.dart' show Disposable;
 export 'observables/observable.dart';
 export 'observables/proxy_observable.dart';
 export 'observers/observer.dart';
+export 'subjects/subject.dart';

lib/src/observables/subjects/subject.dart

@@ -0,0 +1,6 @@
+
+import 'package:disposal/disposal.dart';
+import '../observables/observable.dart';
+import '../observers/observer.dart';
+
+abstract class Subject<T> implements Observable<T>, Observer<T>, Disposable {}

test/observables/observables_test.dart

@@ -9,6 +9,7 @@ import 'observables/proxy_observable_test.dart' as proxy_observable_test;
 import 'observables/skip_observable_test.dart' as skip_observable_test;
 import 'observables/where_observable_test.dart' as where_observable_test;
 import 'observers/observer_test.dart' as observer_test;
+import 'subjects/subject_test.dart' as subject_test;
 
 
 void main() {
@@ -22,4 +23,5 @@ void main() {
   skip_observable_test.main();
   where_observable_test.main();
   observer_test.main();
+  subject_test.main();
 }

test/observables/subjects/subject_test.dart

@@ -0,0 +1,32 @@
+
+import 'package:test/test.dart';
+import 'package:scopes/scopes.dart';
+
+void main() {
+
+  test('subject is observable, observer and disposable', () {
+    final subject = _MockSubject<String>();
+    expect(subject, isA<Observable<String>>());
+    expect(subject, isA<Observer<String>>());
+    expect(subject, isA<Disposable>());
+  });
+
+}
+
+class _MockSubject<T> implements Subject<T> {
+
+  @override
+  Disposable observe(OnData<T> onData) {
+    throw UnimplementedError();
+  }
+
+  @override
+  void onData(T data) {
+    throw UnimplementedError();
+  }
+
+  @override
+  void dispose() {
+    throw UnimplementedError();
+  }
+}