Add appengine/gcloud/mustache dependencies.

pkg/mustache/test/mustache_spec_test.dart

+import 'dart:async';
+import 'dart:io';
+import 'package:mustache/mustache.dart' as mustache;
+import 'dart:convert';
+
+var verbose = false;
+var testName = null;
+var fileName = null; //'test/spec/sections.json';
+
+main(List<String> args) {
+        if (!args.isEmpty) {
+                for (var arg in args) {
+                        if (arg == '--verbose' || arg == '-v') {
+                                verbose = true;
+                        } else if (arg.startsWith('-')) {
+                                print('Unknown argument: $arg');
+                                print('Usage: dart test/mustache_spec_test.dart [--verbose] [test name]');
+                                return;
+                        } else {
+                                testName = arg;
+                                verbose = true;
+                        }
+                }
+        }
+
+        var specs = new Directory('test/spec')
+                .listSync()
+                .where((f) => f is File
+                                    && f.path.endsWith('.json')
+                                    && (fileName == null || f.path == fileName));
+
+        Future.forEach(specs,
+                (file) => file
+                        .readAsString()
+                        .then((s) => JSON.decode(s))
+                        .then((spec) {
+                                print('Specification: ${file.path}');
+                                spec['tests'].forEach((map) => runTest(
+                                        map['name'],
+                                        map['desc'],
+                                        map['data'],
+                                        map['template'],
+                                        map['expected']));
+                                print('');
+                        }));
+}
+
+runTest(String name, String desc, Map data, String template, String expected) {
+        if (testName != null && name != testName)
+                return;
+
+        var output;
+        var exception;
+        var trace;
+        try {
+                output = mustache.parse(template, lenient: true).renderString(data, lenient: true);
+        } catch (ex, stacktrace) {
+                exception = ex;
+                trace = stacktrace;
+        }
+
+//      if (output != null)
+//              output = output.replaceAll('\n', '\\n');
+
+//      if (expected != null)
+//              expected = expected.replaceAll('\n', '\\n');
+
+        var passed = output == expected;
+        var result = passed ? 'Pass' : 'Fail';
+        print('    $result  $name');
+        if (verbose && !passed) {
+                print(desc);
+                print('        Template: $template');
+                print('        Data:     ${JSON.encode(data)}');
+                print('        Expected: $expected');
+                print('        Output:   $output');
+                if (exception != null) print('        Exception: $exception');
+                if (trace != null) print(trace);
+                print('');
+                print('');
+        }
+}
+