build_test 3.2.1

Utilities for writing unit tests of Builders.

Testing utilities for users of package:build.

Installation

This package is intended to only be as a development dependency for users of package:build, and should not be used in any production code. Simply add to your pubspec.yaml:

dev_dependencies:
  build_test: ^3.0.0

Running tests

To run tests, you should go through the dart run build_runner test command. This will compile all your tests to a temp directory and run them using dart run test. If you would like to see the output directory, you can use the --output=<dir> option to force the output to go to a specific place.

Forwarding additional args to dart run test

It is very common to need to pass some arguments through to the eventual call to dart run test. To do this, add all those args after an empty -- arg.

For example, to run all chrome platform tests you would do dart run build_runner test -- -p chrome.

Debugging web tests

This package will automatically create *.debug.html files next to all your *_test.dart files, which can be loaded in a browser from the normal development server (dart run build_runner serve).

Note: In order to run the tests this way, you will need to configure them to be compiled (by default we only compile *.browser_test.dart files). You can do this in your build.yaml file, with something like the following:

targets:
  $default:
    builders:
      build_web_compilers:entrypoint:
        generate_for:
        - test/**_test.dart
        - web/**.dart

You may also view an index of links to every *.debug.html file by navigating to http://localhost:8081 (or wherever your test folder is being served).

Writing tests for your custom Builder

In addition to assiting in running normal tests, this package provides some utilities for testing your custom Builder classes.

See the test folder in the build package for more examples.

Run a Builder within a test environment

Using testBuilder, you can run a functional test of a Builder, including feeding specific assets, and more. It automatically creates an in-memory representation of various utility classes.

Exposing actual package sources to testBuilder

To pass sources on disk to testBuilder, create a TestReaderWriter. You can write individual sources to it from a PackageAssetReader, or write all sources to it with loadIsolateSources:

final readerWriter = TestReaderWriter();
await readerWriter.loadIsolateSources();
testBuilder(
  yourBuilder,
  {} /* test assets here */,
  readerWriter: readerWriter,
);

Resolve source code for testing

Using resolveAsset and resolveSource, you can resolve Dart source code into a static element model, suitable for probing and using within tests of code you might have written for a Builder:

test('should resolve a simple dart file', () async {
  var resolver = await resolveSource(r'''
    library example;

    class Foo {}
  ''');
  var libExample = resolver.getLibraryByName('example');
  expect(libExample.getType('Foo'), isNotNull);
});

Various test implementations of classes

• FakeWatcher
• TestReaderWriter
• PackageAssetReader