tester 0.1.0


An experimental test runner for Dart & Flutter, designed for iterative workflows.

tester #

An experimental test runner, designed for fast incremental test processing workflows and maximum flexibility due to a lack of significant runtime. Currently supports running tests on the Dart VM & Flutter, and within the Chrome browser it can run both Dart Web and Flutter for Web tests. Requires a version of the Flutter SDK that is extremely close to ToT to be present on the PATH, or configured via FLUTTER_ROOT.

setup #

Tester works best when tester/bin is added to your PATH environment variable. The tool itself will self-snapshot, but does not yet support any auto-update functionality.

Running tests #

tester should be run from the project root, the directory containing pubspec.yaml. By default, it will run all files in test/ ending in _test.dart once and exit. It also accepts multiple positional arguments for one or more individual test files.

tester test/a_test.dart test/b_test.dart

The tester can also be started in a resident process that re-runs when test files or library sources are changed.

tester --watch

Writing Tests #

tester uses top-level declarations (beginning with "test") to declare test cases, with dartdoc providing additional context. It cannot use the expect function from package:test, but a similar declaration is available in package:expect.

import 'package:expect/expect.dart';

void testFoo() {
  // asserts are fine too
  assert(foo() == true);

/// Here is a comment that will show up in test logs if it fails.
void testLists() {
  var xs = doThing();
  expect(xs, [1, 2, 3]);

tester may also be run in package:test compatibility mode using --test-compat-mode. This allows tester to execute normal tests, to allow a gradual migration or mixed codebase.

Test Concurrency #

tester runs each test in serial. In batch mode, multiple runners can be configured using --concurrency/-j. The appropriate level of concurrency is automatically inferred based on the number of cores available and size of the given test suites.

tester -j4

Test Platforms #

The test platform (Dart VM, Flutter, Web, Flutter Web) can be configured using --platform. Web platforms require a chrome executable to be available. Running code which uses dart:ui requires the use of either flutter or flutter_web platforms. Code which uses dart:html, dart:js, or other JavaScript interop libraries requires the use of web or flutter_web platforms. dart:mirrors is only supported on the dart platform.

tester --platform=dart test/dart_test.dart
tester --platform=flutter test/flutter_test.dart
tester --platform=web test/flutter_test.dart
tester --platform=flutter_web test/flutter_test.dart

Coverage #

Code coverage can be measured by passing --coverage (batch-mode only for now). This is currently only supported on dart and flutter platforms, and not web or flutter_web.