Add a [prints] matcher to the matcher library.
R=rnystrom@google.com
Review URL: https://codereview.chromium.org//766653005
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/matcher@42270 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4689c31..4e847d8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.11.3
+
+* Add a `prints` matcher that matches output a callback emits via `print`.
+
## 0.11.2
* Add an `isNotEmpty` matcher.
diff --git a/lib/matcher.dart b/lib/matcher.dart
index 6fd18cc..c7790c9 100644
--- a/lib/matcher.dart
+++ b/lib/matcher.dart
@@ -15,6 +15,7 @@
export 'src/map_matchers.dart';
export 'src/numeric_matchers.dart';
export 'src/operator_matchers.dart';
+export 'src/prints_matcher.dart';
export 'src/string_matchers.dart';
export 'src/throws_matcher.dart';
export 'src/throws_matchers.dart';
diff --git a/lib/src/prints_matcher.dart b/lib/src/prints_matcher.dart
new file mode 100644
index 0000000..8faa895
--- /dev/null
+++ b/lib/src/prints_matcher.dart
@@ -0,0 +1,72 @@
+// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library matcher.prints_matcher;
+
+import 'dart:async';
+
+import 'description.dart';
+import 'expect.dart';
+import 'interfaces.dart';
+import 'future_matchers.dart';
+import 'util.dart';
+
+/// Matches a [Function] that prints text that matches [matcher].
+///
+/// [matcher] may be a String or a [Matcher].
+///
+/// If the function this runs against returns a [Future], all text printed by
+/// the function (using [Zone] scoping) until that Future completes is matched.
+///
+/// This only tracks text printed using the [print] function.
+Matcher prints(matcher) => new _Prints(wrapMatcher(matcher));
+
+class _Prints extends Matcher {
+ final Matcher _matcher;
+
+ _Prints(this._matcher);
+
+ bool matches(item, Map matchState) {
+ if (item is! Function) return false;
+
+ var buffer = new StringBuffer();
+ var result = runZoned(item, zoneSpecification:
+ new ZoneSpecification(print: (_, __, ____, line) {
+ buffer.writeln(line);
+ }));
+
+ if (result is! Future) {
+ var actual = buffer.toString();
+ matchState['prints.actual'] = actual;
+ return _matcher.matches(actual, matchState);
+ }
+
+ return completes.matches(result.then(wrapAsync((_) {
+ expect(buffer.toString(), _matcher);
+ }, 'prints')), matchState);
+ }
+
+ Description describe(Description description) =>
+ description.add('prints ').addDescriptionOf(_matcher);
+
+ Description describeMismatch(item, Description description, Map matchState,
+ bool verbose) {
+ var actual = matchState.remove('prints.actual');
+ if (actual == null) return description;
+ if (actual.isEmpty) return description.add("printed nothing.");
+
+ description.add('printed ').addDescriptionOf(actual);
+
+ // Create a new description for the matcher because at least
+ // [_StringEqualsMatcher] replaces the previous contents of the description.
+ var innerMismatch = _matcher.describeMismatch(
+ actual, new StringDescription(), matchState, verbose).toString();
+
+ if (innerMismatch.isNotEmpty) {
+ description.add('\n Which: ').add(innerMismatch.toString());
+ }
+
+ return description;
+ }
+}
diff --git a/pubspec.yaml b/pubspec.yaml
index 230ddc3..1951a5b 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
name: matcher
-version: 0.11.2
+version: 0.11.3
author: Dart Team <misc@dartlang.org>
description: Support for specifying test expectations
homepage: https://pub.dartlang.org/packages/matcher
diff --git a/test/prints_matcher_test.dart b/test/prints_matcher_test.dart
new file mode 100644
index 0000000..183d4ef
--- /dev/null
+++ b/test/prints_matcher_test.dart
@@ -0,0 +1,104 @@
+// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library matcher.prints_matchers_test;
+
+import 'dart:async';
+
+import 'package:matcher/matcher.dart';
+import 'package:unittest/unittest.dart';
+
+import 'test_utils.dart';
+
+void main() {
+ initUtils();
+
+ group('synchronous', () {
+ test("passes with an expected print", () {
+ shouldPass(() => print("Hello, world!"), prints("Hello, world!\n"));
+ });
+
+ test("combines multiple prints", () {
+ shouldPass(() {
+ print("Hello");
+ print("World!");
+ }, prints("Hello\nWorld!\n"));
+ });
+
+ test("works with a Matcher", () {
+ shouldPass(() => print("Hello, world!"), prints(contains("Hello")));
+ });
+
+ test("describes a failure nicely", () {
+ shouldFail(() => print("Hello, world!"), prints("Goodbye, world!\n"),
+ "Expected: prints 'Goodbye, world!\\n' ''"
+ " Actual: <Closure: () => dynamic> "
+ " Which: printed 'Hello, world!\\n' ''"
+ " Which: is different. "
+ "Expected: Goodbye, w ... "
+ " Actual: Hello, wor ... "
+ " ^ Differ at offset 0");
+ });
+
+ test("describes a failure with a non-descriptive Matcher nicely", () {
+ shouldFail(() => print("Hello, world!"), prints(contains("Goodbye")),
+ "Expected: prints contains 'Goodbye'"
+ " Actual: <Closure: () => dynamic> "
+ " Which: printed 'Hello, world!\\n' ''");
+ });
+
+ test("describes a failure with no text nicely", () {
+ shouldFail(() {}, prints(contains("Goodbye")),
+ "Expected: prints contains 'Goodbye'"
+ " Actual: <Closure: () => dynamic> "
+ " Which: printed nothing.");
+ });
+ });
+
+ group('asynchronous', () {
+ test("passes with an expected print", () {
+ shouldPass(() => new Future(() => print("Hello, world!")),
+ prints("Hello, world!\n"));
+ });
+
+ test("combines multiple prints", () {
+ shouldPass(() => new Future(() {
+ print("Hello");
+ print("World!");
+ }), prints("Hello\nWorld!\n"));
+ });
+
+ test("works with a Matcher", () {
+ shouldPass(() => new Future(() => print("Hello, world!")),
+ prints(contains("Hello")));
+ });
+
+ test("describes a failure nicely", () {
+ shouldFail(() => new Future(() => print("Hello, world!")),
+ prints("Goodbye, world!\n"),
+ "Expected: 'Goodbye, world!\\n' ''"
+ " Actual: 'Hello, world!\\n' ''"
+ " Which: is different. "
+ "Expected: Goodbye, w ... "
+ " Actual: Hello, wor ... "
+ " ^ Differ at offset 0",
+ isAsync: true);
+ });
+
+ test("describes a failure with a non-descriptive Matcher nicely", () {
+ shouldFail(() => new Future(() => print("Hello, world!")),
+ prints(contains("Goodbye")),
+ "Expected: contains 'Goodbye'"
+ " Actual: 'Hello, world!\\n' ''",
+ isAsync: true);
+ });
+
+ test("describes a failure with no text nicely", () {
+ shouldFail(() => new Future.value(), prints(contains("Goodbye")),
+ "Expected: contains 'Goodbye'"
+ " Actual: ''",
+ isAsync: true);
+ });
+ });
+}
