Minor cleanup to tests. (#9197)

packages/flutter/test/material/date_picker_test.dart

@@ -53,6 +53,7 @@ void main() {
         ],
       ),
     );
+    expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 26)));
 
     await tester.tapAt(const Point(50.0, 100.0));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 26)));

packages/flutter/test/material/refresh_indicator_test.dart

@@ -30,7 +30,7 @@ void main() {
           children: <String>['A', 'B', 'C', 'D', 'E', 'F'].map((String item) {
             return new SizedBox(
               height: 200.0,
-              child: new Text(item)
+              child: new Text(item),
             );
           }).toList(),
         ),

packages/flutter/test/widgets/page_view_test.dart

@@ -60,8 +60,7 @@ void main() {
     expect(log, equals(<String>['Alaska']));
     log.clear();
 
-    await tester.fling(
-        find.byType(PageView), const Offset(-200.0, 0.0), 1000.0);
+    await tester.fling(find.byType(PageView), const Offset(-200.0, 0.0), 1000.0);
     await tester.pumpAndSettle(_frameDuration);
 
     expect(find.text('Alabama'), findsNothing);