Testing on the Dart track

Learn how to test your Dart exercises on Exercism


Download an Exercise

Use the Exercism CLI to download the exercise you want to work on.

exercism download --track=dart --exercise=hello-world

Then change into the exercise directory.

cd /path/to/exercism/dart/hello-world

Install Dependencies

Before running the tests, download the exercise dependencies.

dart pub get

Run the Tests

dart test

Understanding Test Results

dart test uses the compact reporter by default, showing a running count of tests passed, skipped, and failed on a single line.

$ dart test
00:00 +1 -1: test/binary_search_test.dart: finds a value in the middle of an array [E]
  Expected: <3>
    Actual: <0>

  package:matcher                    expect
  test/binary_search_test.dart 13:5  main.<fn>


To run this test again: dart test test/binary_search_test.dart -p vm --plain-name 'finds a value in the middle of an array'
00:00 +1 ~9 -1: Some tests failed.
  • +1 — 1 test passed
  • ~9 — 9 tests skipped
  • -1 — 1 test failed

For more detailed per-test output, use the expanded reporter, which shows each test result as it runs.

$ dart test -r expanded
00:00 +0: loading test/binary_search_test.dart
00:00 +0: test/binary_search_test.dart: finds a value in an array with one element
00:00 +1: test/binary_search_test.dart: finds a value in the middle of an array
00:00 +1 -1: test/binary_search_test.dart: finds a value in the middle of an array [E]
  Expected: <3>
    Actual: <0>
  
  package:matcher                    expect
  test/binary_search_test.dart 13:5  main.<fn>
  
00:00 +1 -1: test/binary_search_test.dart: finds a value at the beginning of an array
00:00 +1 ~1 -1: test/binary_search_test.dart: finds a value at the end of an array
00:00 +1 ~2 -1: test/binary_search_test.dart: finds a value in an array of odd length
00:00 +1 ~3 -1: test/binary_search_test.dart: finds a value in an array of even length
00:00 +1 ~4 -1: test/binary_search_test.dart: identifies that a value is not included in the array
00:00 +1 ~5 -1: test/binary_search_test.dart: a value smaller than the array's smallest value is not found
00:00 +1 ~6 -1: test/binary_search_test.dart: a value larger than the array's largest value is not found
00:00 +1 ~7 -1: test/binary_search_test.dart: nothing is found in an empty array
00:00 +1 ~8 -1: test/binary_search_test.dart: nothing is found when the left and right bounds cross
00:00 +1 ~9 -1: Some tests failed.

Working Through Tests

Most exercises have multiple tests, with all but the first skipped by default.

void main() {
  final twoFer = TwoFer();

  group('TwoFer', () {
    test('no name given', () {
      final result = twoFer.statement();
      expect(result, equals('One for you, one for me.'));
    }, skip: false);

    test('a name given', () {
      final result = twoFer.statement('Alice');
      expect(result, equals('One for Alice, one for me.'));
    }, skip: true);

    test('another name given', () {
      final result = twoFer.statement('Bob');
      expect(result, equals('One for Bob, one for me.'));
    }, skip: true);
  });
}

To work through tests one at a time, change skip: true to skip: false on each test as you go. Alternatively, run all tests at once without editing the file.

dart test --run-skipped

All tests are run by the online test runner on submission, including skipped ones.