Added a toString() and a test. (#313)

Author: matanlurey

CHANGELOG.md

@@ -1,3 +1,10 @@
+## 0.7.5+1
+
+* `LibraryBuilder` and `PartBuilder` now have a more readable `toString()`,
+  which is useful when emitting a warning or error in a build system. For
+  example you may see `Generating .g.dart: MyBuilder` instead of
+  `Instance of LibraryBuilder` in your build logs.
+
 ## 0.7.5
 
 * The `PartBuilder` constructor parameter `requireLibraryDirective` now defaults

lib/src/builder.dart

@@ -154,6 +154,11 @@ class _Builder extends Builder {
     // ignore: unawaited_futures
     buildStep.writeAsString(outputId, genPartContent);
   }
+
+  @override
+  String toString() {
+    return 'Generating $_generatedExtension: ${_generators.join(', ')}';
+  }
 }
 
 /// A [Builder] which generates `part of` files.

pubspec.yaml

@@ -1,5 +1,5 @@
 name: source_gen
-version: 0.7.5
+version: 0.7.5+1
 author: Dart Team <[email protected]>
 description: Automated source code generation for Dart.
 homepage: https://github.com/dart-lang/source_gen

test/builder_test.dart

@@ -215,6 +215,17 @@ void main() {
     expect(
         logs.map((l) => l.message), contains(contains('$pkgName|lib/a.dart')));
   });
+
+  test('Should have a readable toString() message for builders', () {
+    final builder = new LibraryBuilder(new _NoOpGenerator());
+    expect(builder.toString(), 'Generating .g.dart: NOOP');
+
+    final builders = new PartBuilder([
+      new _NoOpGenerator(),
+      new _NoOpGenerator(),
+    ]);
+    expect(builders.toString(), 'Generating .g.dart: NOOP, NOOP');
+  });
 }
 
 Future _generateTest(CommentGenerator gen, String expectedContent) async {
@@ -241,12 +252,17 @@ Map<String, String> _createPackageStub(String pkgName,
 /// Doesn't generate output for any element
 class _NoOpGenerator extends Generator {
   const _NoOpGenerator();
+
   @override
   Future<String> generate(LibraryReader library, _) => null;
+
+  @override
+  String toString() => 'NOOP';
 }
 
 class _BadOutputGenerator extends Generator {
   const _BadOutputGenerator();
+
   @override
   Future<String> generate(LibraryReader library, _) async => 'not valid code!';
 }