Create a package that implements a JSON-RPC 2.0 server.

pkg/json_rpc_2/test/server/invalid_request_test.dart

+// 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 json_rpc_2.test.server.invalid_request_test;
+
+import 'dart:convert';
+
+import 'package:unittest/unittest.dart';
+import 'package:json_rpc_2/error_code.dart' as error_code;
+import 'package:json_rpc_2/json_rpc_2.dart' as json_rpc;
+
+import 'utils.dart';
+
+void main() {
+  var server;
+  setUp(() => server = new json_rpc.Server());
+
+  test("a non-Array/Object request is invalid", () {
+    expectErrorResponse(server, 'foo', error_code.INVALID_REQUEST,
+        'Requests must be Arrays or Objects.');

[Bob Nystrom, 2014/03/20 18:25:58]

I think this error message should be singular.

[nweiz, 2014/03/20 22:55:41]

Done.

+  });
+
+  test("requests must have a jsonrpc key", () {
+    expectErrorResponse(server, {
+      'method': 'foo',
+      'id': 1234
+    }, error_code.INVALID_REQUEST, 'Requests must contain a "jsonrpc" key.');

[Bob Nystrom, 2014/03/20 18:25:58]

Ditto.

[nweiz, 2014/03/20 22:55:41]

Done.

+  });
+
+  test("the jsonrpc version must be 2.0", () {
+    expectErrorResponse(server, {
+      'jsonrpc': '1.0',
+      'method': 'foo',
+      'id': 1234
+    },
+        error_code.INVALID_REQUEST,

[Bob Nystrom, 2014/03/20 18:25:58]

Nit: move this to the previous line? Here and below.

[nweiz, 2014/03/20 22:55:41]

Done.

+        'Invalid JSON-RPC version "1.0", expected "2.0".');
+  });
+
+  test("requests must have a method key", () {
+    expectErrorResponse(server, {
+      'jsonrpc': '2.0',
+      'id': 1234
+    }, error_code.INVALID_REQUEST, 'Requests must contain a "method" key.');
+  });
+
+  test("request method must be a string", () {
+    expectErrorResponse(server, {
+      'jsonrpc': '2.0',
+      'method': 1234,
+      'id': 1234
+    },
+        error_code.INVALID_REQUEST,
+        'Request method must be a string, but was "1234".');
+  });
+
+  test("request params must be an Array or Object", () {
+    expectErrorResponse(server, {
+      'jsonrpc': '2.0',
+      'method': 'foo',
+      'params': 1234,
+      'id': 1234
+    },
+        error_code.INVALID_REQUEST,
+        'Request params must be an Array or an Object, but was "1234".');
+  });
+
+  test("request id must be an Array or Object", () {

[Bob Nystrom, 2014/03/20 18:25:58]

Fix description.

+    expect(server.handleRequest({
+      'jsonrpc': '2.0',
+      'method': 'foo',
+      'id': {'bad': 'id'}
+    }), completion(equals({
+      'jsonrpc': '2.0',
+      'id': null,
+      'error': {
+        'code': error_code.INVALID_REQUEST,
+        'message': 'Request id must be a string, number, or null, but was '
+            '"{bad: id}".',
+        'data': {'request': {
+          'jsonrpc': '2.0',
+          'method': 'foo',
+          'id': {'bad': 'id'}
+        }}
+      }
+    })));
+  });
+}