Add tests for Message

lib/http.dart

@@ -14,8 +14,7 @@ export 'src/base_client.dart';
 export 'src/client.dart';
 export 'src/exception.dart';
 export 'src/io_client.dart';
-export 'src/multipart_file.dart';
-export 'src/multipart_request.dart';
+export 'src/middleware.dart';
 export 'src/request.dart';
 export 'src/response.dart';
 

pubspec.yaml

@@ -10,6 +10,9 @@ dependencies:
   path: ">=0.9.0 <2.0.0"
   stack_trace: ">=0.9.1 <2.0.0"
 dev_dependencies:
-  unittest: ">=0.9.0 <0.12.0"
+  test: "^0.12.18"
+# Override dependency on package_resolver to enable test
+dependency_overrides:
+  package_resolver: '^1.0.0'
 environment:
   sdk: ">=1.24.0-dev.0.0 <2.0.0"

test/message_change_test.dart

@@ -0,0 +1,100 @@
+// Copyright (c) 2017, 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.
+
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:test/test.dart';
+
+import 'package:http/http.dart';
+import 'package:http/src/message.dart';
+
+final _uri = Uri.parse('http://localhost/');
+
+void main() {
+  group('Request', () {
+    _testChange(({body, headers, context}) {
+      return new Request('GET', _uri,
+          body: body, headers: headers, context: context);
+    });
+  });
+
+  group('Response', () {
+    _testChange(({body, headers, context}) {
+      return new Response(_uri, 200,
+          body: body, headers: headers, context: context);
+    });
+  });
+}
+
+/// Shared test method used by [Request] and [Response] tests to validate
+/// the behavior of `change` with different `headers` and `context` values.
+void _testChange(
+    Message factory(
+        {body, Map<String, String> headers, Map<String, Object> context})) {
+  group('body', () {
+    test('with String', () async {
+      var request = factory(body: 'Hello, world');
+      var copy = request.change(body: 'Goodbye, world');
+
+      var newBody = await copy.readAsString();
+
+      expect(newBody, equals('Goodbye, world'));
+    });
+
+    test('with Stream', () async {
+      var request = factory(body: 'Hello, world');
+      var copy = request.change(
+          body: new Stream.fromIterable(['Goodbye, world'])
+              .transform(UTF8.encoder));
+
+      var newBody = await copy.readAsString();
+
+      expect(newBody, equals('Goodbye, world'));
+    });
+  });
+
+  test('with empty headers returns identical instance', () {
+    var request = factory(headers: {'header1': 'header value 1'});
+    var copy = request.change(headers: {});
+
+    expect(copy.headers, same(request.headers));
+  });
+
+  test('with empty context returns identical instance', () {
+    var request = factory(context: {'context1': 'context value 1'});
+    var copy = request.change(context: {});
+
+    expect(copy.context, same(request.context));
+  });
+
+  test('new header values are added', () {
+    var request = factory(headers: {'test': 'test value'});
+    var copy = request.change(headers: {'test2': 'test2 value'});
+
+    expect(copy.headers,
+        {'test': 'test value', 'test2': 'test2 value', 'content-length': '0'});
+  });
+
+  test('existing header values are overwritten', () {
+    var request = factory(headers: {'test': 'test value'});
+    var copy = request.change(headers: {'test': 'new test value'});
+
+    expect(copy.headers, {'test': 'new test value', 'content-length': '0'});
+  });
+
+  test('new context values are added', () {
+    var request = factory(context: {'test': 'test value'});
+    var copy = request.change(context: {'test2': 'test2 value'});
+
+    expect(copy.context, {'test': 'test value', 'test2': 'test2 value'});
+  });
+
+  test('existing context values are overwritten', () {
+    var request = factory(context: {'test': 'test value'});
+    var copy = request.change(context: {'test': 'new test value'});
+
+    expect(copy.context, {'test': 'new test value'});
+  });
+}