pkg/vm_service/test/get_cpu_samples_rpc_test.dart

// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. 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:test/test.dart';
import 'package:vm_service/vm_service.dart';

import 'common/test_helper.dart';

int fib(n) {
  if (n < 0) return 0;
  if (n == 0) return 1;
  return fib(n - 1) + fib(n - 2);
}

void testeeDo() {
  print('Testee doing something.');
  fib(44);
  print('Testee did something.');
}

Future<void> checkSamples(VmService service, IsolateRef isolate) async {
  // Grab all the samples.
  final isolateId = isolate.id!;
  final result = await service.getCpuSamples(isolateId, 0, ~0);

  final isString = TypeMatcher<String>();
  final isInt = TypeMatcher<int>();
  final isList = TypeMatcher<List>();
  expect(
    result.functions!.length,
    greaterThan(10),
    reason: 'Should have many functions!',
  );

  final samples = result.samples!;
  expect(samples.length, greaterThan(0), reason: 'Should have samples');
  expect(samples.length, result.sampleCount);

  final sample = samples.first;
  expect(sample.tid, isInt);
  expect(sample.timestamp, isInt);
  if (sample.vmTag != null) {
    expect(sample.vmTag, isString);
  }
  if (sample.userTag != null) {
    expect(sample.userTag, isString);
  }
  expect(sample.stack, isList);
}

final tests = <IsolateTest>[
  checkSamples,
];

const vmArgs = <String>[
  '--profiler=true',
  // Crank up the sampling rate to make sure we get samples.
  '--profile_period=100',
  '--profile-vm=false', // So this also works with KBC.
];

void main([args = const <String>[]]) => runIsolateTests(
      args,
      tests,
      'get_cpu_samples_rpc_test.dart',
      testeeBefore: testeeDo,
      extraArgs: vmArgs,
    );