Merge pull request #79 from a-givertzman/TextFile-write

Text file write

lib/src/core/text_file.dart

@@ -1,25 +1,43 @@
 import 'dart:io';
 import 'package:flutter/services.dart';
-///
-abstract class TextFile {
-  ///
+/// The interface for reading and writing a text file.
+abstract interface class TextFile {
+  /// Text file from the file system.
+  /// 
+  /// `filePath` - file system valid relative or full path to the file.
   const factory TextFile.path(String filePath) = _PathTextFile;
-  ///
+  /// Text file from application asset bundle. 
+  /// 
+  /// `assetPath` - path to the file according to your `assets` section in `pubspec.yaml`.
   const factory TextFile.asset(String assetPath) = _AssetTextFile;
   ///
+  /// Internal file contents as text.
   Future<String> get content;
+  /// 
+  /// Rewrites the entire file with provided `text`.
+  Future<void> write(String text);
 }
 ///
 class _PathTextFile implements TextFile {
   final String _filePath;
   const _PathTextFile(this._filePath);
+  //
   @override
   Future<String> get content => File(_filePath).readAsString();
+  //
+  @override
+  Future<void> write(String text) => File(_filePath).writeAsString(text, flush: true);
 }
 ///
 class _AssetTextFile implements TextFile {
   final String _assetPath;
   const _AssetTextFile(this._assetPath);
+  //
   @override
   Future<String> get content => rootBundle.loadString(_assetPath);
+  //
+  @override
+  Future<void> write(String text) {
+    throw UnimplementedError('Unable to write to asset file.');
+  }
 }

test/unit/core/entities/app_settings/fake_text_file.dart

@@ -2,8 +2,12 @@ import 'package:hmi_core/src/core/text_file.dart';
 ///
 class FakeTextFile implements TextFile {
   final String text;
-  const FakeTextFile(this.text);
+  final Future<void>? writeFuture;
+  const FakeTextFile(this.text, {this.writeFuture});
   //
   @override
   Future<String> get content => Future.value(text);
+  //
+  @override
+  Future<void> write(String text) => writeFuture ?? Future(() {return;});
 }

test/unit/core/text_file/text_file_asset_read_test.dart

@@ -0,0 +1,20 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:hmi_core/src/core/text_file.dart';
+
+void main() {
+  WidgetsFlutterBinding.ensureInitialized();
+  const testAssetPath = 'assets/test/test.txt';
+  const originalContent = 'test\nasset\ntext';
+  group('TextFile.asset(...).read()', () {
+    test('reads existing bundle file correctly', () async {
+      const textFile = TextFile.asset(testAssetPath);
+      final receivedContent = await textFile.content;
+      expect(originalContent, equals(receivedContent));
+    });
+    test('throws error on unexisting bundle file', () async {
+      const textFile = TextFile.asset('assets/unexisting_asset.txt');
+      expect(() async => await textFile.content, throwsA(isA<Error>()));
+    });
+  });
+}

test/unit/core/text_file/text_file_path_read_test.dart

@@ -0,0 +1,43 @@
+import 'dart:io';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:hmi_core/src/core/text_file.dart';
+
+void main() {
+  const testFileNamePrefix = 'text_file_path_write_test';
+  const contentToWrite = [
+    'first line some test text 12345\nsecond line some test text 12345\n',
+    '',
+    '0123456789',
+    'abcdefghijklmnopqrstuvwxyz',
+    'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+    'абвгдеёжзийклмнопрстуфхцчшщъыьэюя',
+    'АБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ',
+    '!@#\$%^&*()_+=-"№;:?./\\|[]{}',
+  ];
+  group('TextFile.asset(...).read()', () {
+    setUpAll(() async {
+      await Future.wait([
+        for(int i=0; i < contentToWrite.length; i++) 
+          File('$testFileNamePrefix-$i.txt').writeAsString(contentToWrite[i]),
+      ]);
+    });
+    tearDownAll(() async {
+      await Future.wait([
+        for(int i=0; i < contentToWrite.length; i++) 
+          File('$testFileNamePrefix-$i.txt').delete(),
+      ]);
+    });
+    test('reads local file correctly', () async {
+      for(int i=0; i < contentToWrite.length; i++) {
+        final fileName = '$testFileNamePrefix-$i.txt';
+        final textFile = TextFile.path(fileName);
+        final receivedContent = await textFile.content;
+        expect(receivedContent, equals(contentToWrite[i]));
+      }
+    });
+    test('throws error on unexisting file', () async {
+      const textFile = TextFile.path('unexisting_asset_file.txt');
+      expect(() async => await textFile.content, throwsA(isA<PathNotFoundException>()));
+    });
+  });
+}

test/unit/core/text_file/text_file_path_write_test.dart

@@ -0,0 +1,37 @@
+import 'dart:io';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:hmi_core/src/core/text_file.dart';
+
+void main() {
+  const testFileNamePrefix = 'text_file_path_write_test';
+  const contentToWrite = [
+    'first line some test text 12345\nsecond line some test text 12345\n',
+    '',
+    '0123456789',
+    'abcdefghijklmnopqrstuvwxyz',
+    'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+    'абвгдеёжзийклмнопрстуфхцчшщъыьэюя',
+    'АБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ',
+    '!@#\$%^&*()_+=-"№;:?./\\|[]{}',
+  ];
+  setUpAll(() async {
+    await Future.wait([
+      for(int i=0; i < contentToWrite.length; i++) 
+        File('$testFileNamePrefix-$i.txt').create(),
+    ]);
+  });
+  tearDownAll(() async {
+    await Future.wait([
+      for(int i=0; i < contentToWrite.length; i++) 
+        File('$testFileNamePrefix-$i.txt').delete(),
+    ]);
+  });
+  test('TextFile.path(...).write() writes local file correctly', () async {
+    for(int i=0; i < contentToWrite.length; i++) {
+      final testFilePath = '$testFileNamePrefix-$i.txt';
+      final textFile = TextFile.path(testFilePath);
+      await textFile.write(contentToWrite[i]);
+      expect(await File(testFilePath).readAsString(), equals(contentToWrite[i]));
+    }
+  });
+}