wip: unit test SimpleLogRecordProcessor

Author: yuzurihaaa

Diff for: test/unit/sdk/logs/processors/simple_log_record_processor_test.dart

@@ -0,0 +1,90 @@
+// 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
+
+@TestOn('vm')
+import 'dart:async';
+
+import 'package:fixnum/fixnum.dart';
+import 'package:logging/logging.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:opentelemetry/sdk.dart' as sdk;
+import 'package:opentelemetry/src/experimental_sdk.dart' as sdk;
+import 'package:opentelemetry/src/sdk/logs/log_record_limit.dart';
+import 'package:opentelemetry/src/sdk/logs/processors/simple_log_record_processor.dart';
+import 'package:test/test.dart';
+
+import '../../../mocks.dart';
+
+void main() {
+  late sdk.LogRecordExporter exporter;
+  late sdk.LogRecordProcessor processor;
+
+  setUp(() {
+    exporter = MockLogRecordExporter();
+    processor = SimpleLogRecordProcessor(exporter: exporter);
+    when(() => exporter.export(any())).thenAnswer((_) async => sdk.ExportResult(code: sdk.ExportResultCode.success));
+    when(() => exporter.shutdown()).thenAnswer((_) => Future.value());
+  });
+
+  test('executes export', () {
+    final logRecord = sdk.LogRecord(
+      instrumentationScope: sdk.InstrumentationScope('library_name', 'library_version', 'url://schema', []),
+      logRecordLimits: LogRecordLimitsImpl(),
+    );
+
+    processor.onEmit(logRecord);
+
+    verify(() => exporter.export([logRecord])).called(1);
+  });
+
+  test('executes export and fail', () async {
+    var errorMessage = '';
+    Logger.root.onRecord.listen((data) {
+      errorMessage = data.message;
+    });
+    final logRecord = sdk.LogRecord(
+      instrumentationScope: sdk.InstrumentationScope('library_name', 'library_version', 'url://schema', []),
+      logRecordLimits: LogRecordLimitsImpl(),
+    );
+
+    when(() => exporter.export(any())).thenAnswer((_) async => sdk.ExportResult(code: sdk.ExportResultCode.failed));
+
+    processor.onEmit(logRecord);
+
+    await Future.delayed(const Duration(milliseconds: 50));
+
+    expect(errorMessage, 'SimpleLogRecordProcessor: log record export failed');
+  });
+
+  test('shutdown exporters on forced flush', () async {
+    await processor.shutdown();
+
+    verify(exporter.shutdown).called(1);
+  });
+
+  test('forceFlush waits for all pending exports to complete', () async {
+    when(() => exporter.export(any())).thenAnswer((_) async {
+      await Future.delayed(const Duration(seconds: 1));
+      return sdk.ExportResult(code: sdk.ExportResultCode.success);
+    });
+
+    // Emit two log records, creating two pending exports.
+    processor.onEmit(
+      sdk.LogRecord(
+          instrumentationScope: sdk.InstrumentationScope('library_name', 'library_version', 'url://schema', []),
+          logRecordLimits: LogRecordLimitsImpl(),
+          timeProvider: FakeTimeProvider(now: Int64(123))),
+    );
+    await Future.delayed(Duration(milliseconds: 50));
+    processor.onEmit(
+      sdk.LogRecord(
+          instrumentationScope: sdk.InstrumentationScope('library_name', 'library_version', 'url://schema', []),
+          logRecordLimits: LogRecordLimitsImpl(),
+          timeProvider: FakeTimeProvider(now: Int64(123))),
+    );
+    expect((processor as SimpleLogRecordProcessor).exportsCompletion.length, 2);
+    // Ensure the exports are pending.
+    final flushFuture = processor.forceFlush();
+    expect(flushFuture, completes);
+  });
+}