wip: add InMemoryLogRecordExporter

Author: yuzurihaaa

lib/src/experimental_sdk.dart

@@ -14,6 +14,7 @@ export 'sdk/logs/processors/log_record_processor.dart' show LogRecordProcessor;
 export 'sdk/logs/processors/noop_log_processor.dart' show NoopLogRecordProcessor;
 export 'sdk/logs/processors/batch_log_record_processor.dart' show BatchLogRecordProcessor;
 export 'sdk/logs/exporters/console_log_record_exporter.dart' show ConsoleLogRecordExporter;
+export 'sdk/logs/exporters/inmemory_log_record_exporter.dart' show InMemoryLogRecordExporter;
 export 'sdk/logs/exporters/log_record_exporter.dart' show LogRecordExporter;
 export 'sdk/logs/log_record_limit.dart' show LogRecordLimits;
 export 'sdk/metrics/counter.dart' show Counter;

lib/src/sdk/logs/exporters/inmemory_log_record_exporter.dart

@@ -0,0 +1,43 @@
+// Copyright 2021-2022 Workiva.
+// Licensed under the Apache License, Version 2.0. Please see https://github.com/Workiva/opentelemetry-dart/blob/master/LICENSE for more information
+
+import 'package:meta/meta.dart';
+import 'package:opentelemetry/src/experimental_sdk.dart' as sdk;
+
+/// This class can be used for testing purposes. It stores the exported LogRecords
+/// in a list in memory that can be retrieved using the `getFinishedLogRecords()`
+/// method.
+class InMemoryLogRecordExporter implements sdk.LogRecordExporter {
+  var _finishedLogRecords = <sdk.ReadableLogRecord>[];
+
+  /// Indicates if the exporter has been "shutdown."
+  /// When false, exported log records will not be stored in-memory.
+  @protected
+  bool _stopped = false;
+
+  @override
+  Future<sdk.ExportResult> export(List<sdk.ReadableLogRecord> logs) async {
+    if (_stopped) {
+      return sdk.ExportResult(
+        code: sdk.ExportResultCode.failed,
+        error: Exception('Exporter has been stopped'),
+        stackTrace: StackTrace.current,
+      );
+    }
+    _finishedLogRecords.addAll(logs);
+
+    return sdk.ExportResult(code: sdk.ExportResultCode.success);
+  }
+
+  @override
+  Future<void> shutdown() async {
+    _stopped = true;
+    reset();
+  }
+
+  List<sdk.ReadableLogRecord> get finishedLogRecords => List.unmodifiable(_finishedLogRecords);
+
+  void reset() {
+    _finishedLogRecords = <sdk.ReadableLogRecord>[];
+  }
+}