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.
Handling error "Could not find a command named frontend_server.dart.snapshot"
Suppose you have an exercise you've already solved and submitted, and you're coming back to it after a while.
You may encounter this error when you test it:
$ dart test
...
Could not find a command named "/path/to/frontend_server.dart.snapshot".
The solution is to delete the pubspec.lock file.
Then run the dart command again.
