Add shared_preferences (#15)

packages/shared_preferences/test/shared_preferences_elinux_test.dart

@@ -0,0 +1,84 @@
+// Copyright 2021 Sony Group Corporation. All rights reserved.
+// Copyright 2013 The Flutter Authors. 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:file/memory.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:path/path.dart' as path;
+import 'package:path_provider_elinux/path_provider_elinux.dart';
+import 'package:shared_preferences_elinux/shared_preferences_elinux.dart';
+import 'package:shared_preferences_platform_interface/shared_preferences_platform_interface.dart';
+
+void main() {
+  late MemoryFileSystem fs;
+
+  SharedPreferencesELinux.registerWith();
+
+  setUp(() {
+    fs = MemoryFileSystem.test();
+  });
+
+  Future<String> _getFilePath() async {
+    final pathProvider = PathProviderLinux();
+    final directory = await pathProvider.getApplicationSupportPath();
+    return path.join(directory!, 'shared_preferences.json');
+  }
+
+  _writeTestFile(String value) async {
+    fs.file(await _getFilePath())
+      ..createSync(recursive: true)
+      ..writeAsStringSync(value);
+  }
+
+  Future<String> _readTestFile() async {
+    return fs.file(await _getFilePath()).readAsStringSync();
+  }
+
+  SharedPreferencesLinux _getPreferences() {
+    var prefs = SharedPreferencesLinux();
+    prefs.fs = fs;
+    return prefs;
+  }
+
+  test('registered instance', () {
+    expect(
+        SharedPreferencesStorePlatform.instance, isA<SharedPreferencesLinux>());
+  });
+
+  test('getAll', () async {
+    await _writeTestFile('{"key1": "one", "key2": 2}');
+    var prefs = _getPreferences();
+
+    var values = await prefs.getAll();
+    expect(values, hasLength(2));
+    expect(values['key1'], 'one');
+    expect(values['key2'], 2);
+  });
+
+  test('remove', () async {
+    await _writeTestFile('{"key1":"one","key2":2}');
+    var prefs = _getPreferences();
+
+    await prefs.remove('key2');
+
+    expect(await _readTestFile(), '{"key1":"one"}');
+  });
+
+  test('setValue', () async {
+    await _writeTestFile('{}');
+    var prefs = _getPreferences();
+
+    await prefs.setValue('', 'key1', 'one');
+    await prefs.setValue('', 'key2', 2);
+
+    expect(await _readTestFile(), '{"key1":"one","key2":2}');
+  });
+
+  test('clear', () async {
+    await _writeTestFile('{"key1":"one","key2":2}');
+    var prefs = _getPreferences();
+
+    await prefs.clear();
+    expect(await _readTestFile(), '{}');
+  });
+}