[WIP] Refactoring - Separate and Test Weekdays row

lib/flutter_calendar_carousel.dart

@@ -7,6 +7,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_calendar_carousel/classes/event_list.dart';
 import 'package:flutter_calendar_carousel/src/default_styles.dart';
 import 'package:flutter_calendar_carousel/src/calendar_header.dart';
+import 'package:flutter_calendar_carousel/src/weekday_row.dart';
 import 'package:intl/date_symbol_data_local.dart';
 import 'package:intl/intl.dart' show DateFormat;
 
@@ -216,13 +217,12 @@ class _CalendarState<T> extends State<CalendarCarousel<T>> {
                 ? widget.onHeaderTitlePressed
                 : () => _selectDateFromPicker(),
           ),
-          Container(
-            child: !widget.showWeekDays
-                ? Container()
-                : Row(
-                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
-                    children: _renderWeekDays(),
-                  ),
+          WeekdayRow(
+            showWeekdays: widget.showWeekDays,
+            weekdayFormat: widget.weekDayFormat,
+            weekdayMargin: widget.weekDayMargin,
+            weekdayTextStyle: widget.weekdayTextStyle,
+            localeDate: _localeDate,
           ),
           Expanded(
               child: PageView.builder(
@@ -788,58 +788,6 @@ class _CalendarState<T> extends State<CalendarCarousel<T>> {
     }
   }
 
-  List<Widget> _renderWeekDays() {
-    List<Widget> list = [];
-
-    /// because of number of days in a week is 7, so it would be easier to count it til 7.
-    for (var i = firstDayOfWeek, count = 0;
-        count < 7;
-        i = (i + 1) % 7, count++) {
-      String weekDay;
-
-      switch (widget.weekDayFormat) {
-        case WeekdayFormat.weekdays:
-          weekDay = _localeDate.dateSymbols.WEEKDAYS[i];
-          break;
-        case WeekdayFormat.standalone:
-          weekDay = _localeDate.dateSymbols.STANDALONEWEEKDAYS[i];
-          break;
-        case WeekdayFormat.short:
-          weekDay = _localeDate.dateSymbols.SHORTWEEKDAYS[i];
-          break;
-        case WeekdayFormat.standaloneShort:
-          weekDay = _localeDate.dateSymbols.STANDALONESHORTWEEKDAYS[i];
-          break;
-        case WeekdayFormat.narrow:
-          weekDay = _localeDate.dateSymbols.NARROWWEEKDAYS[i];
-          break;
-        case WeekdayFormat.standaloneNarrow:
-          weekDay = _localeDate.dateSymbols.STANDALONENARROWWEEKDAYS[i];
-          break;
-        default:
-          weekDay = _localeDate.dateSymbols.STANDALONEWEEKDAYS[i];
-          break;
-      }
-
-      list.add(
-        Expanded(
-            child: Container(
-          margin: widget.weekDayMargin,
-          child: Center(
-            child: DefaultTextStyle(
-              style: defaultWeekdayTextStyle,
-              child: Text(
-                weekDay,
-                style: widget.weekdayTextStyle,
-              ),
-            ),
-          ),
-        )),
-      );
-    }
-    return list;
-  }
-
   Widget _renderMarked(DateTime now) {
     if (widget.markedDates != null && widget.markedDates.length > 0) {
       List<DateTime> markedDates = widget.markedDates.map((date) {

lib/src/weekday_row.dart

@@ -0,0 +1,75 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_calendar_carousel/flutter_calendar_carousel.dart';
+import 'package:flutter_calendar_carousel/src/default_styles.dart'
+    show defaultWeekdayTextStyle;
+import 'package:intl/intl.dart';
+
+class WeekdayRow extends StatelessWidget {
+  WeekdayRow(
+      {@required this.showWeekdays,
+      @required this.weekdayFormat,
+      @required this.weekdayMargin,
+      @required this.weekdayTextStyle,
+      @required this.localeDate});
+
+  final bool showWeekdays;
+  final WeekdayFormat weekdayFormat;
+  final EdgeInsets weekdayMargin;
+  final TextStyle weekdayTextStyle;
+  final DateFormat localeDate;
+
+  Widget _weekdayContainer(String weekDay) => Expanded(
+          child: Container(
+        margin: weekdayMargin,
+        child: Center(
+          child: DefaultTextStyle(
+            style: defaultWeekdayTextStyle,
+            child: Text(
+              weekDay,
+              style: weekdayTextStyle,
+            ),
+          ),
+        ),
+      ));
+
+  List<Widget> _generateWeekdays() {
+    switch (weekdayFormat) {
+      case WeekdayFormat.weekdays:
+        return localeDate.dateSymbols.WEEKDAYS
+            .map<Widget>(_weekdayContainer)
+            .toList();
+      case WeekdayFormat.standalone:
+        return localeDate.dateSymbols.STANDALONEWEEKDAYS
+            .map<Widget>(_weekdayContainer)
+            .toList();
+      case WeekdayFormat.short:
+        return localeDate.dateSymbols.SHORTWEEKDAYS
+            .map<Widget>(_weekdayContainer)
+            .toList();
+      case WeekdayFormat.standaloneShort:
+        return localeDate.dateSymbols.STANDALONESHORTWEEKDAYS
+            .map<Widget>(_weekdayContainer)
+            .toList();
+      case WeekdayFormat.narrow:
+        return localeDate.dateSymbols.NARROWWEEKDAYS
+            .map<Widget>(_weekdayContainer)
+            .toList();
+      case WeekdayFormat.standaloneNarrow:
+        return localeDate.dateSymbols.STANDALONENARROWWEEKDAYS
+            .map<Widget>(_weekdayContainer)
+            .toList();
+      default:
+        return localeDate.dateSymbols.STANDALONEWEEKDAYS
+            .map<Widget>(_weekdayContainer)
+            .toList();
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) => showWeekdays
+      ? Row(
+          mainAxisAlignment: MainAxisAlignment.spaceBetween,
+          children: _generateWeekdays(),
+        )
+      : Container();
+}

test/src/weekday_row_test.dart

@@ -0,0 +1,102 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_calendar_carousel/flutter_calendar_carousel.dart'
+    show WeekdayFormat;
+import 'package:intl/intl.dart' show DateFormat;
+
+import 'package:flutter_calendar_carousel/src/weekday_row.dart';
+import 'package:flutter/material.dart';
+
+void main() {
+  final locale = DateFormat.yMMM("en_US");
+  final margin = const EdgeInsets.only(bottom: 4.0);
+
+  testWidgets('test short weekday row', (WidgetTester tester) async {
+    await tester.pumpWidget(wrapped(
+      WeekdayRow(
+        showWeekdays: true,
+        weekdayFormat: WeekdayFormat.short,
+        weekdayMargin: margin,
+        weekdayTextStyle: null,
+        localeDate: locale,
+      ),
+    ));
+
+    expect(find.text('Sun'), findsOneWidget);
+    expect(find.text('Mon'), findsOneWidget);
+    expect(find.text('Tue'), findsOneWidget);
+    expect(find.text('Wed'), findsOneWidget);
+    expect(find.text('Thu'), findsOneWidget);
+    expect(find.text('Fri'), findsOneWidget);
+    expect(find.text('Sat'), findsOneWidget);
+  });
+
+  testWidgets('test narrow weekday row', (WidgetTester tester) async {
+    await tester.pumpWidget(wrapped(WeekdayRow(
+      showWeekdays: true,
+      weekdayFormat: WeekdayFormat.standaloneNarrow,
+      weekdayMargin: margin,
+      weekdayTextStyle: null,
+      localeDate: locale,
+    )));
+
+    // sat and sun
+    expect(find.text('S'), findsNWidgets(2));
+    // thurs and tues
+    expect(find.text('T'), findsNWidgets(2));
+
+    expect(find.text('M'), findsOneWidget);
+    expect(find.text('W'), findsOneWidget);
+    expect(find.text('F'), findsOneWidget);
+  });
+
+  testWidgets('test standalone weekday row', (WidgetTester tester) async {
+    await tester.pumpWidget(wrapped(WeekdayRow(
+      showWeekdays: true,
+      weekdayFormat: WeekdayFormat.standalone,
+      weekdayMargin: margin,
+      weekdayTextStyle: null,
+      localeDate: locale,
+    )));
+
+    expect(find.text('Sunday'), findsOneWidget);
+    expect(find.text('Monday'), findsOneWidget);
+    expect(find.text('Tuesday'), findsOneWidget);
+    expect(find.text('Wednesday'), findsOneWidget);
+    expect(find.text('Thursday'), findsOneWidget);
+    expect(find.text('Friday'), findsOneWidget);
+    expect(find.text('Saturday'), findsOneWidget);
+  });
+
+  testWidgets('test standalone short weekday row', (WidgetTester tester) async {
+    await tester.pumpWidget(wrapped(WeekdayRow(
+      showWeekdays: true,
+      weekdayFormat: WeekdayFormat.standaloneShort,
+      weekdayMargin: margin,
+      weekdayTextStyle: null,
+      localeDate: locale,
+    )));
+
+    expect(find.text('Sun'), findsOneWidget);
+    expect(find.text('Mon'), findsOneWidget);
+    expect(find.text('Tue'), findsOneWidget);
+    expect(find.text('Wed'), findsOneWidget);
+    expect(find.text('Thu'), findsOneWidget);
+    expect(find.text('Fri'), findsOneWidget);
+    expect(find.text('Sat'), findsOneWidget);
+  });
+
+  testWidgets('test row does not render', (WidgetTester tester) async {
+    final emptyContainer = WeekdayRow(showWeekdays: false);
+
+    await tester.pumpWidget(emptyContainer);
+
+    expect(find.byType(Container), findsOneWidget);
+
+    expect(find.byType(Row), findsNothing);
+  });
+}
+
+Widget wrapped(Widget widget) => Directionality(
+      textDirection: TextDirection.ltr,
+      child: widget,
+    );