Add flutter_web samples (#75)

web/charts/flutter/test/user_managed_state_test.dart

@@ -0,0 +1,128 @@
+// Copyright 2018 the Charts project authors. Please see the AUTHORS file
+// for details.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'package:flutter_web/widgets.dart';
+import 'package:flutter_web_test/flutter_web_test.dart';
+
+import 'package:charts_flutter/flutter.dart' as charts;
+
+void main() {
+  testWidgets('selection can be set programmatically',
+      (WidgetTester tester) async {
+    final onTapSelection =
+        new charts.UserManagedSelectionModel<String>.fromConfig(
+            selectedDataConfig: [
+          new charts.SeriesDatumConfig<String>('Sales', '2016')
+        ]);
+
+    charts.SelectionModel<String> currentSelectionModel;
+
+    void selectionChangedListener(charts.SelectionModel<String> model) {
+      currentSelectionModel = model;
+    }
+
+    final testChart = new TestChart(selectionChangedListener, onTapSelection);
+
+    await tester.pumpWidget(testChart);
+
+    expect(currentSelectionModel, isNull);
+
+    await tester.tap(find.byType(charts.BarChart));
+
+    await tester.pump();
+
+    expect(currentSelectionModel.selectedDatum, hasLength(1));
+    final selectedDatum =
+        currentSelectionModel.selectedDatum.first.datum as OrdinalSales;
+    expect(selectedDatum.year, equals('2016'));
+    expect(selectedDatum.sales, equals(100));
+    expect(currentSelectionModel.selectedSeries, hasLength(1));
+    expect(currentSelectionModel.selectedSeries.first.id, equals('Sales'));
+  });
+}
+
+class TestChart extends StatefulWidget {
+  final charts.SelectionModelListener<String> selectionChangedListener;
+  final charts.UserManagedSelectionModel<String> onTapSelection;
+
+  TestChart(this.selectionChangedListener, this.onTapSelection);
+
+  @override
+  TestChartState createState() {
+    return new TestChartState(selectionChangedListener, onTapSelection);
+  }
+}
+
+class TestChartState extends State<TestChart> {
+  final charts.SelectionModelListener<String> selectionChangedListener;
+  final charts.UserManagedSelectionModel<String> onTapSelection;
+
+  final seriesList = _createSampleData();
+  final myState = new charts.UserManagedState<String>();
+
+  TestChartState(this.selectionChangedListener, this.onTapSelection);
+
+  @override
+  Widget build(BuildContext context) {
+    final chart = new charts.BarChart(
+      seriesList,
+      userManagedState: myState,
+      selectionModels: [
+        new charts.SelectionModelConfig(
+            type: charts.SelectionModelType.info,
+            changedListener: widget.selectionChangedListener)
+      ],
+      // Disable animation and gesture for testing.
+      animate: false, //widget.animate,
+      defaultInteractions: false,
+    );
+
+    return new GestureDetector(child: chart, onTap: handleOnTap);
+  }
+
+  void handleOnTap() {
+    setState(() {
+      myState.selectionModels[charts.SelectionModelType.info] = onTapSelection;
+    });
+  }
+}
+
+/// Create one series with sample hard coded data.
+List<charts.Series<OrdinalSales, String>> _createSampleData() {
+  final data = [
+    new OrdinalSales('2014', 5),
+    new OrdinalSales('2015', 25),
+    new OrdinalSales('2016', 100),
+    new OrdinalSales('2017', 75),
+  ];
+
+  return [
+    new charts.Series<OrdinalSales, String>(
+      id: 'Sales',
+      colorFn: (_, __) => charts.MaterialPalette.blue.shadeDefault,
+      domainFn: (OrdinalSales sales, _) => sales.year,
+      measureFn: (OrdinalSales sales, _) => sales.sales,
+      data: data,
+    )
+  ];
+}
+
+/// Sample ordinal data type.
+class OrdinalSales {
+  final String year;
+  final int sales;
+
+  OrdinalSales(this.year, this.sales);
+}