FileOutput tests: Use MemoryFileSystem instead of real file system

Author: Bungeefan

lib/src/outputs/advanced_file_output.dart

@@ -2,6 +2,8 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:meta/meta.dart';
+
 import '../log_level.dart';
 import '../log_output.dart';
 import '../output_event.dart';
@@ -94,8 +96,9 @@ class AdvancedFileOutput extends LogOutput {
             ],
         _maxRotatedFilesCount = maxRotatedFilesCount,
         _fileSorter = fileSorter ?? _defaultFileSorter,
-        _fileUpdateDuration = fileUpdateDuration,
-        _file = maxFileSizeKB > 0 ? File('$path/$latestFileName') : File(path);
+        _fileUpdateDuration = fileUpdateDuration {
+    _file = createFile(maxFileSizeKB > 0 ? '$path/$latestFileName' : path);
+  }
 
   /// Logs directory path by default, particular log file path if [_maxFileSizeKB] is 0.
   final String _path;
@@ -115,7 +118,7 @@ class AdvancedFileOutput extends LogOutput {
   final Comparator<File> _fileSorter;
   final Duration _fileUpdateDuration;
 
-  final File _file;
+  late final File _file;
   IOSink? _sink;
   Timer? _bufferFlushTimer;
   Timer? _targetFileUpdater;
@@ -142,14 +145,18 @@ class AdvancedFileOutput extends LogOutput {
     return a.lastModifiedSync().compareTo(b.lastModifiedSync());
   }
 
+  @protected
+  File createFile(String path) {
+    return File(path);
+  }
+
   @override
   Future<void> init() async {
     if (_rotatingFilesMode) {
-      final dir = Directory(_path);
       // We use sync directory check to avoid losing potential initial boot logs
       // in early crash scenarios.
-      if (!dir.existsSync()) {
-        dir.createSync(recursive: true);
+      if (!_file.parent.existsSync()) {
+        _file.parent.createSync(recursive: true);
       }
 
       _targetFileUpdater = Timer.periodic(
@@ -232,8 +239,7 @@ class AdvancedFileOutput extends LogOutput {
     // If maxRotatedFilesCount is not set, keep all files
     if (_maxRotatedFilesCount == null) return;
 
-    final dir = Directory(_path);
-    final files = dir
+    final files = _file.parent
         .listSync()
         .whereType<File>()
         // Filter out the latest file

lib/src/outputs/advanced_file_output_stub.dart

@@ -1,6 +1,8 @@
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:meta/meta.dart';
+
 import '../log_level.dart';
 import '../log_output.dart';
 import '../output_event.dart';
@@ -76,6 +78,11 @@ class AdvancedFileOutput extends LogOutput {
     throw UnsupportedError("Not supported on this platform.");
   }
 
+  @protected
+  File createFile(String path) {
+    throw UnsupportedError("Not supported on this platform.");
+  }
+
   @override
   void output(OutputEvent event) {
     throw UnsupportedError("Not supported on this platform.");

pubspec.yaml

@@ -10,9 +10,13 @@ topics:
 environment:
   sdk: ">=2.17.0 <4.0.0"
 
+dependencies:
+  meta: ^1.16.0
+
 dev_dependencies:
   test: ^1.16.8
   lints: ^2.0.1
+  file: ">=6.0.0 <8.0.0"
 
 platforms:
   android:

test/outputs/advanced_file_output_test.dart

@@ -1,24 +1,53 @@
 import 'dart:io';
 
+import 'package:file/memory.dart';
 import 'package:logger/logger.dart';
 import 'package:test/test.dart';
 
-void main() {
-  var file = File("${Directory.systemTemp.path}/dart_advanced_logger_test.log");
-  var dir = Directory("${Directory.systemTemp.path}/dart_advanced_logger_dir");
-  setUp(() async {
-    await file.create(recursive: true);
-    await dir.create(recursive: true);
+var memory = MemoryFileSystem();
+
+class MemoryAdvancedFileOutput extends AdvancedFileOutput {
+  MemoryAdvancedFileOutput({
+    required super.path,
+    super.maxDelay,
+    super.maxFileSizeKB,
+    super.writeImmediately,
+    super.maxRotatedFilesCount,
+    super.fileNameFormatter,
+    super.fileSorter,
+    super.fileHeader,
+    super.fileFooter,
   });
 
-  tearDown(() async {
-    await file.delete();
-    await dir.delete(recursive: true);
+  late File _file;
+
+  get file => _file;
+
+  @override
+  File createFile(String path) {
+    return _file = memory.file(path);
+  }
+}
+
+void main() {
+  final fileName = "dart_advanced_logger_test.log";
+  final dirName = "dart_advanced_logger_dir";
+
+  tearDown(() {
+    var file = memory.file(fileName);
+    if (file.existsSync()) {
+      file.deleteSync();
+    }
+
+    var directory = memory.directory(dirName);
+    if (directory.existsSync()) {
+      directory.deleteSync(recursive: true);
+    }
   });
 
   test('Real file read and write with buffer accumulation', () async {
-    var output = AdvancedFileOutput(
-      path: file.path,
+    var output = MemoryAdvancedFileOutput(
+      path: fileName,
       maxDelay: const Duration(milliseconds: 500),
       maxFileSizeKB: 0,
     );
@@ -32,12 +61,9 @@ void main() {
     output.output(event1);
     output.output(event2);
 
-    // Wait until buffer is flushed to file
-    await Future.delayed(const Duration(seconds: 1));
-
     await output.destroy();
 
-    var content = await file.readAsString();
+    var content = await output.file.readAsString();
     expect(
       content,
       allOf(
@@ -50,8 +76,8 @@ void main() {
 
   test('Real file read and write with rotating file names and immediate output',
       () async {
-    var output = AdvancedFileOutput(
-      path: dir.path,
+    var output = MemoryAdvancedFileOutput(
+      path: dirName,
       writeImmediately: [Level.info],
     );
     await output.init();
@@ -66,8 +92,7 @@ void main() {
 
     await output.destroy();
 
-    final logFile = File('${dir.path}/latest.log');
-    var content = await logFile.readAsString();
+    var content = await output.file.readAsString();
     expect(
       content,
       allOf(
@@ -79,8 +104,8 @@ void main() {
   });
 
   test('Rolling files', () async {
-    var output = AdvancedFileOutput(
-      path: dir.path,
+    var output = MemoryAdvancedFileOutput(
+      path: dirName,
       maxFileSizeKB: 1,
     );
     await output.init();
@@ -100,17 +125,16 @@ void main() {
     output.output(event2);
     await output.destroy();
 
-    final files = dir.listSync();
-
+    final files = output.file.parent.listSync();
     expect(
       files,
       (hasLength(3)),
     );
   });
 
   test('Rolling files with rotated files deletion', () async {
-    var output = AdvancedFileOutput(
-      path: dir.path,
+    var output = MemoryAdvancedFileOutput(
+      path: dirName,
       maxFileSizeKB: 1,
       maxRotatedFilesCount: 1,
     );
@@ -120,34 +144,25 @@ void main() {
     output.output(event0);
     await output.destroy();
 
-    // TODO Find out why test is so flaky with durations <1000ms
-    // Give the OS a chance to flush to the file system (should reduce flakiness)
-    await Future.delayed(const Duration(milliseconds: 1000));
-
     // Start again to roll files on init without waiting for timer tick
     await output.init();
     final event1 = OutputEvent(LogEvent(Level.fatal, ""), ["2" * 1500]);
     output.output(event1);
     await output.destroy();
 
-    await Future.delayed(const Duration(milliseconds: 1000));
-
     // And again for another roll
     await output.init();
     final event2 = OutputEvent(LogEvent(Level.fatal, ""), ["3" * 1500]);
     output.output(event2);
     await output.destroy();
 
-    await Future.delayed(const Duration(milliseconds: 1000));
-
-    final files = dir.listSync();
-
+    final latestFile = output.file;
+    final files = latestFile.parent.listSync();
     // Expect only 2 files: the "latest" that is the current log file
     // and only one rotated file. The first created file should be deleted.
     expect(files, hasLength(2));
-    final latestFile = File('${dir.path}/latest.log');
-    final rotatedFile = dir
-        .listSync()
+
+    final rotatedFile = files
         .whereType<File>()
         .firstWhere((file) => file.path != latestFile.path);
     expect(await latestFile.readAsString(), contains("3"));
@@ -158,8 +173,8 @@ void main() {
     const fileHeader = "TEST-HEADER";
     const fileFooter = "TEST-FOOTER";
 
-    var output = AdvancedFileOutput(
-      path: dir.path,
+    var output = MemoryAdvancedFileOutput(
+      path: dirName,
       maxFileSizeKB: 1,
       maxRotatedFilesCount: 1,
       fileHeader: fileHeader,
@@ -172,23 +187,23 @@ void main() {
     output.output(event0);
     await output.destroy();
 
-    // Give the OS a chance to flush to the file system (should reduce flakiness)
-    await Future.delayed(const Duration(milliseconds: 1000));
-
-    final latestFile = File('${dir.path}/latest.log');
+    final latestFile = output.file;
     expect(await latestFile.readAsString(), startsWith(fileHeader));
     expect(await latestFile.readAsString(), endsWith("$fileFooter\n"));
   });
 
   test('Rolling files with custom file sorter', () async {
-    var output = AdvancedFileOutput(
-      path: dir.path,
+    int fileNameCounter = 0;
+    var output = MemoryAdvancedFileOutput(
+      path: dirName,
       maxFileSizeKB: 1,
       maxRotatedFilesCount: 1,
       // Define a custom file sorter that sorts files by their length
       // (strange behavior for testing purposes) from the longest to
       // the shortest: the longest file should be deleted first.
       fileSorter: (a, b) => b.lengthSync().compareTo(a.lengthSync()),
+      // The default uses date time until milliseconds and sometimes this test is faster and would re-use the same name multiple times.
+      fileNameFormatter: (timestamp) => "${fileNameCounter++}.log",
     );
 
     await output.init();
@@ -203,31 +218,27 @@ void main() {
     output.output(event1);
     await output.destroy();
 
-    // Give the OS a chance to flush to the file system (should reduce flakiness)
-    await Future.delayed(const Duration(milliseconds: 50));
-
     // And again for another roll
     await output.init();
     final event2 = OutputEvent(LogEvent(Level.fatal, ""), ["3" * 1500]);
     output.output(event2);
     await output.destroy();
 
-    final files = dir.listSync();
-
+    final latestFile = output.file;
+    final files = latestFile.parent.listSync();
     // Expect only 2 files: the "latest" that is the current log file
     // and only one rotated file (the shortest one).
     expect(files, hasLength(2));
-    final latestFile = File('${dir.path}/latest.log');
-    final rotatedFile = dir
-        .listSync()
+
+    final rotatedFile = files
         .whereType<File>()
         .firstWhere((file) => file.path != latestFile.path);
     expect(await latestFile.readAsString(), contains("3"));
     expect(await rotatedFile.readAsString(), contains("1"));
   });
 
   test('Flush temporary buffer on destroy', () async {
-    var output = AdvancedFileOutput(path: dir.path);
+    var output = MemoryAdvancedFileOutput(path: dirName);
     await output.init();
 
     final event0 = OutputEvent(LogEvent(Level.info, ""), ["Last event"]);
@@ -238,8 +249,7 @@ void main() {
 
     await output.destroy();
 
-    final logFile = File('${dir.path}/latest.log');
-    var content = await logFile.readAsString();
+    var content = await output.file.readAsString();
     expect(
       content,
       allOf(

test/outputs/file_output_test.dart

@@ -1,16 +1,16 @@
-import 'dart:io';
-
+import 'package:file/memory.dart';
 import 'package:logger/logger.dart';
 import 'package:test/test.dart';
 
+var memory = MemoryFileSystem();
+
 void main() {
-  var file = File("${Directory.systemTemp.path}/dart_logger_test.log");
-  setUp(() async {
-    await file.create(recursive: true);
-  });
+  final file = memory.file("dart_logger_test.log");
 
-  tearDown(() async {
-    await file.delete();
+  tearDown(() {
+    if (file.existsSync()) {
+      file.deleteSync();
+    }
   });
 
   test('Real file read and write', () async {