add web_dashboard API (#333)

* add web_dashboard sample

* add docs

* address code review comments

* restructure web_dashboard

* set up provider and mock service

* add copyright headers, use relative imports

* add API class, add tests

* fmt

* rename services -> API, remove data library

* use new API in app

* add stream to items api

* convert from StreamBuilder to StreamProvider

* add subscription to Entry API

* rename API classes

* address comments

* Update README.md

* update README

* remove routing_demo

experimental/web_dashboard/test/mock_service_test.dart

@@ -0,0 +1,97 @@
+// Copyright 2020, the Flutter 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:test/test.dart';
+
+import 'package:web_dashboard/src/api/api.dart';
+import 'package:web_dashboard/src/api/mock.dart';
+
+void main() {
+  group('mock dashboard API', () {
+    DashboardApi api;
+
+    setUp(() {
+      api = MockDashboardApi();
+    });
+
+    group('items', () {
+      test('insert', () async {
+        var item = await api.items.insert(Item('Coffees Drank'));
+        expect(item.name, 'Coffees Drank');
+      });
+
+      test('delete', () async {
+        await api.items.insert(Item('Coffees Drank'));
+        var item2 = await api.items.insert(Item('Miles Ran'));
+        var removed = await api.items.delete(item2.id);
+
+        expect(removed.name, 'Miles Ran');
+
+        var items = await api.items.list();
+        expect(items, hasLength(1));
+      });
+
+      test('update', () async {
+        var item = await api.items.insert(Item('Coffees Drank'));
+        await api.items.update(Item('Bagels Consumed'), item.id);
+
+        var latest = await api.items.get(item.id);
+        expect(latest.name, equals('Bagels Consumed'));
+      });
+      test('subscribe', () async {
+        var stream = api.items.allItemsStream();
+
+        stream.listen(expectAsync1((x) {
+          expect(x, hasLength(1));
+          expect(x.first.name, equals('Coffees Drank'));
+        }, count: 1));
+        await api.items.insert(Item('Coffees Drank'));
+      });
+    });
+
+    group('entry service', () {
+      Item item;
+      DateTime dateTime = DateTime(2020, 1, 1, 30, 45);
+
+      setUp(() async {
+        item = await api.items.insert(Item('Lines of code committed'));
+      });
+
+      test('insert', () async {
+        var entry = await api.entries.insert(item.id, Entry(1, dateTime));
+
+        expect(entry.value, 1);
+        expect(entry.time, dateTime);
+      });
+
+      test('delete', () async {
+        await api.entries.insert(item.id, Entry(1, dateTime));
+        var entry2 = await api.entries.insert(item.id, Entry(2, dateTime));
+
+        await api.entries.delete(item.id, entry2.id);
+
+        var entries = await api.entries.list(item.id);
+        expect(entries, hasLength(1));
+      });
+
+      test('update', () async {
+        var entry = await api.entries.insert(item.id, Entry(1, dateTime));
+        var updated =
+            await api.entries.update(item.id, entry.id, Entry(2, dateTime));
+        expect(updated.value, 2);
+      });
+
+      test('subscribe', () async {
+        var stream = api.entries.allEntriesStream(item.id);
+
+        stream.listen(expectAsync1((x) {
+          expect(x, hasLength(1));
+          expect(x.first.value, equals(1));
+        }, count: 1));
+
+        api.entries.insert(item.id, Entry(1, dateTime));
+      });
+    });
+  });
+}