build_test 3.5.6

build_test: ^3.5.6 copied to clipboard

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Test helpers for build_runner builders.

• In-memory builds
• In-memory builds with real sources
• Resolving source code

In-memory builds #

The testBuilders method provides a way to run builds in memory for small, self contained tests. See the test folder in the build package for examples.

In-memory builds with real sources #

To pass sources on disk to testBuilders, create a TestReaderWriter.

You can write individual sources to it from a PackageAssetReader, or write all sources to it with loadIsolateSources:

final readerWriter = TestReaderWriter(rootPackage: 'test_package');
await readerWriter.testing.loadIsolateSources();
testBuilder(
  yourBuilder,
  {'test_package|lib/a.dart': '''
import 'package:real_package/annotations.dart';

@RealAnnotation()
class TestClass {}
'''},
  readerWriter: readerWriter,
);

Resolving source code #

Use resolveAsset or resolveSource to resolve code with the analyzer:

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);
});

Get generated source code as String #

You can use TestReaderWriter to read generated assets as String. Read more about how this works in the TestReaderWriter documentation.

Set flattenOutput to true in testBuilder to make the output assets accessible:

final yourBuilder = ...;

final readerWriter = TestReaderWriter(rootPackage: 'test_package');

final result = await testBuilder(
  yourBuilder,
  {...},
  readerWriter: readerWriter,
  outputs: null,
  flattenOutput: true,
);


// You can read all of the generated assets like this...
for (final AssetId asset in result.outputs) {
  print('reading generated asset: ${asset}');
  print('  can read: ${await readerWriter.canRead(asset)}');
  print('  exists: ${await readerWriter.testing.exists(asset)}');
  print('  content: \n${await readerWriter.testing.readString(asset)}');
}

// ...or access a single generated asset directly, like this:
final String generatedCode = await readerWriter.testing.readString(
  AssetId('test_package', 'lib/source_file.g.dart')
);
// ...and, for example, use it in tests:
expect(generatedCode, contains('callExpectedFunction();'));