add tests & README

Author: jeebb

README.md

@@ -1,14 +1,36 @@
-# availability
+# Availability
 
-A new Flutter package project.
+A simple if-else widget renderer in an object-oriented way. You can find it similar to Visibility, but with WidgetBuilder usage. With this, the child widget is not put into context until the condition is satisfied.
+
+#code-for-fun
 
 ## Getting Started
 
-This project is a starting point for a Dart
-[package](https://flutter.dev/developing-packages/),
-a library module containing code that can be shared easily across
-multiple Flutter or Dart projects.
 
-For help getting started with Flutter, view our 
-[online documentation](https://flutter.dev/docs), which offers tutorials, 
-samples, guidance on mobile development, and a full API reference.
+### Usage:
+```dart
+Availability(
+    available: <condition>,
+    childBuilder: (BuildContext context) => <widget>,
+)
+```
+
+or 
+
+```dart
+Availability(
+    available: <condition>,
+    childBuilder: (BuildContext context) => <widget>,
+    elseBuilder: (BuildContext context) => <another_widget>,
+)
+```
+
+*** Similar dart code without Availability:
+
+```dart
+if (<condition>) {
+    return <widget>;
+} else {
+    return <another_widget>;
+}
+```

test/availability_test.dart

@@ -0,0 +1,86 @@
+import 'package:availability/availability.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets(
+    'The child widget is rendered correctly',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        _testableWidget(
+          Availability(
+            available: true,
+            childBuilder: (_) => Text('qwerty'),
+          ),
+        ),
+      );
+
+      await tester.pumpAndSettle();
+
+      expect(find.text('qwerty'), findsOneWidget);
+      expect(find.byType(SizedBox), findsNothing);
+    },
+  );
+
+  testWidgets(
+    'The child widget is rendered correctly with elseBuilder defined',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        _testableWidget(
+          Availability(
+            available: true,
+            childBuilder: (_) => Text('qwerty'),
+            elseBuilder: (_) => Text('azerty'),
+          ),
+        ),
+      );
+
+      await tester.pumpAndSettle();
+
+      expect(find.text('qwerty'), findsOneWidget);
+      expect(find.text('azerty'), findsNothing);
+    },
+  );
+
+  testWidgets(
+    'The child widget is not rendered and shrinked SizedBox is rendered',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        _testableWidget(
+          Availability(
+            available: false,
+            childBuilder: (_) => Text('qwerty'),
+          ),
+        ),
+      );
+
+      await tester.pumpAndSettle();
+
+      expect(find.text('qwerty'), findsNothing);
+      expect(find.byType(SizedBox), findsOneWidget);
+    },
+  );
+
+  testWidgets(
+    'The else builder is triggered correctly',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        _testableWidget(
+          Availability(
+            available: false,
+            childBuilder: (_) => Text('qwerty'),
+            elseBuilder: (_) => Text('azerty'),
+          ),
+        ),
+      );
+
+      await tester.pumpAndSettle();
+
+      expect(find.text('qwerty'), findsNothing);
+      expect(find.text('azerty'), findsOneWidget);
+      expect(find.byType(SizedBox), findsNothing);
+    },
+  );
+}
+
+Widget _testableWidget(Widget widget) => MaterialApp(home: widget);